III. PACKS

Day Packs | Weekender Packs | Packboards

In the collecting of a climbing or camping outfit the pack rates first consideration. In it go most of the other items of equipment and whether they are light or heavy they have to be carried on the back! An uncomfortable pack has ruined many an otherwise pleasant trip. It stands to reason, therefore, that the best possible planning and design considerations should go into this pivotal piece of equipment.

Back packs fall into three categories: the small frameless sack type; the rucksack type with a frame but designed to hang away from the back; and the pack board type which is designed to be supported on the back.

A thing to be remembered about every pack is that when it is stuffed with a sleeping bag and other equipment it tends to as­sume a cylindrical shape unless it is restrained. Any simple sack stuffed to overflowing will become as round as a small beer keg and it will be just as uncomfortable on the back. For this reason it is always a good idea to have a pack slightly larger than is actually needed so that it needn't be stuffed.

There is only one way to force the small frameless pack to keep its shape—by the use of partitions. This prevents the pack from bulging and at the same time divides it into convenient compart­ments. The next best thing would be a large sack with relatively little in it. This type of frameless pack has to be very carefully packed to prevent cans, crampons and such hard things from dig­ging into the back. For this reason it is now generally reserved for the light loads required on one-day trips.

The introduction of the frame rucksack in Europe was an effort to produce a more comfortable pack. The frame served the triple purpose of keeping the shape of the pack despite the load, keeping the load off the wearer's back, and allowing air circulation next to the back for coolness.

For light loads the conventional frame rucksack such as the original Bergen from Norway has the one cardinal advantage of a low center of gravity which makes it a very comfortable pack for climbing and skiing. Due to its numerous pockets and compart­ments it is also very convenient to use. Most people will find, however, that it has a definite weight limit. It is designed so that the top of the sack hangs away from the back. This creates a backward pull on the shoulders! With loads over twenty to thirty pounds, depending on the weight of the person carrying the load, this backward pull is very uncomfortable and the energy expended in resisting it is needlessly wasted. (The heavier the person the heavier the load he can carry this way.)

Heavier loads are more comfortably carried supported on the back with the center of gravity over the hips. For this purpose a pack board frame, either with or without an attached sack should be used.

Figure 1, Plate II, shows a tracing of a photograph of a person actually carrying over 100 pounds in a frame rucksack. Figure 2 shows the same person with a packboard and sack superimposed on his stance. The large cross approximates the point about which the packs tend to pivot. It is obvious that the rucksack is pulling the person backward with a good deal of force while the pack-board supports the load against the back.

A pack board frame can be distinguished by a fabric panel or several wide bands which will support the load comfortably along the length of the back and not just the lower part. The sack itself is cut so that the load is held close to the back and stacked rather high so that with a slight forward lean of the body the center of gravity of the load is placed directly over the hips. This tends to tip the top of the pack forward onto the back in contrast to the action of the rucksack, the top of which hangs away from the back. Too high a load exerts considerable leverage against the body's natural balance and can be tiring, for anything except straight walking.

In addition, placement of the straps and everything else possible is done to increase the tendency to tip the load forward. However, it must be realized that by improper packing a pack board can also pull backward on the shoulders as badly as any rucksack. The load must be close to the body and relatively high to realize full efficiency from the pack board design.

Many designs of sacks with pack board frames have the same compartments and pockets as a rucksack which make them very convenient as well as comfortable for heavy loads.

Of the several types of pack boards available, those that are curved to fit the back either vertically or horizontally and which provide some means of ventilation for the back are the best.

Those having a flat, tightly laced canvas panel against the back are the least desirable.

There are factors other than weight limits to be considered in the choice of a pack. For instance, for a one-day trip the load will be light and an inexpensive frameless sack can be used. If this sack is compartmented it will be more comfortable because it holds its shape well, and in addition it will be more convenient to find belongings.

A pack large enough to hold a sleeping bag is necessary for weekending. Here a frame rucksack comes into its own. The main sack easily holds a sleeping bag and large items, leaving the pockets free for the small items which tend to get lost in the shuffle in a large sack. The weight of the load is kept low for comfort.

For longer trips packboards with sacks become necessary. The sack will be more convenient if it has the outside pockets of the rucksack for ease in reaching small items. The large capacity of the main sack will take care of the extra food needed on longer trips. A light tent can be carried when desirable. One unique design in this type of pack carries the sack itself high leaving the lower third of the pack board free for lashing on the sleeping bag in its own waterproof cover. This guarantees the heavier items will be packed high and farther forward than the light sleeping bag, though it is rather hard on the sleeping bag in rough country.

Some packs in this size range are built to carry the load high over the shoulders, This is fine for trails, open terrain and glacier packing; however the center of gravity is not only a little too high for comfortable climbing but the pack tends to limit movement of the head backward. This stymies the climber who can't lean backward to see above.

In large scale expedition work on which a lot of miscellaneous gear must be packed, a large pack board with generous lashing hooks and a shelf at the bottom is necessary. Here again in open terrain a board on which the load can be stacked high over the shoulders is fine. For bushwacking or difficult climbing a board with a lower center of gravity is necessary. It is a good idea to have a detachable sack for such a pack board. Where necessary this can carry personal gear leaving the pack board completely free for cases of food, cans of gasoline and bulky equipment. Another weight saving feature is the attachment of shoulder straps to the sack so it can be used alone as a one-day pack.

One very specialized pack is the ski pack, designed especially to carry a pair of skis. Skis, off the feet, are about the most miser­able pieces of equipment ever thought up for back packing. Ski packs are designed with a space behind the side pockets through which the tails of the skis are passed. By strapping the ski tips together a fairly rigid "A" is formed—probably the least incon­venient way to carry them. Fig. 9, Plate IV, illustrates a type of ski carrier that can be added to any pack.

To be comfortable the pack should fit the person carrying it. It is often difficult to get a well fitted pack in the desired design from the usual manufacturers, though several make them in various sizes. One good reason for making a personal pack is that it can be custom tailored. In beginning a pack design it should be borne in mind that the load should not extend out too far from the back. The width of the pack can vary most but should not be too wide or it will interfere with the elbows as they swing with the walk. Custom fitting is not absolutely necessary in all cases. All dimensions given for packs are for average size people and can be scaled up or down as necessary.

The arrangement of the straps that bear on the body is the crucial part of the fit and therefore should be made to measure. The main points to determine placement of these bearing straps are as follows:

1.  Lower shoulder strap attachment is near the bottom of the pack.

2.  Bottom of the back band or panel that will support the load against the back should rest slightly below the beltline on the slope of the buttocks. This can vary in position and the most comfortable position should be determined by experiment. Experimenting might consist of trying on an old pack and noting carefully whether it is comfortable, where it rests, etc.   Borrowing various packs to check them for comfortable and uncomfortable features is a good way to settle on design.  This kind of experimentation will pay off when construction of a pack begins or when design modifications are wanted.

3.  With the back band in its most comfortable position the upper shoulder straps should be attached so that they form an angle of about 45° with the pack after they leave the curve of the shoulders.   If the straps are attached too high the pack will drop down until the straps assume this angle. This puts the back band too low. If attached too low, the pack will hang nicely on the back, but with a high packed load the pack will sway from side to side. Compromises will be made and no pack will be perfect for all conditions but the chances are that a little thought given to these considera­tions will result in a pack superior to most manufactured products.

4.  The upper shoulder straps should be placed close enough together to pass over the shoulders close to the neck.  If they are attached far apart on the sack they will pass over the shoulders too far from the neck and exert a good deal of uncomfortable leverage.  (See Fig. 3, Plate II.) The standard fabric for packs in years past has been a good grade of 10 to 12 oz. double filled army duck. This is a very strong, abrasion resistant, and very water repellent fabric by virtue of its tight weave.

Though a good cotton duck makes a fine pack, where light weight is important the same strength and durability can be ob­tained from about a 6 ounce nylon, and for a super light pack it is possible to go down to a 3 or 4 ounce nylon. However, there is the old problem of waterproofing nylon which was discussed in the materials section. Nylon cannot be as closely woven as cotton duck. Because of this fact and nylon's filament peculiarities com­mercial repellent treatments may last only a year.
Regardless of which fabric is used for packs, except in the very lightest designs, the pack bottoms should be reinforced. This is the part of the pack which will wear out long before the rest of the pack. This reinforcing should cover not only the bottom itself but about l½" of the sides and sometimes the bottoms of any side pockets. (Side pocket bottoms should be reinforced when they are low enough to come into contact with the ground when the pack is set down.) Double or triple fabric layers make good reinforcing as does a good grade of chrome tanned garment leather (goatskin, calfskin, pigskin or capeskin). Leather reinforcing should always be sewn over the fabric before the pack is assembled and never used in place of the fabric. In this way the fabric itself takes the strain of the load and the leather resists the abrasion. (See Figs. 3 and 4, Plate III.)

For the very best packs the hardware should be of a solid non-rusting material. Aluminum and stainless steel are rare. The most commonly available material is nickel plated brass. Stay away from painted (japanned) steel; it will nick and rust. Good cadmium plate works well for parts that don't get rubbed too much but will eventually rub off and allow rust. Buckles and snap hooks from army equipment are usually brass under the black oxide finish. Buckles that need adjustment only rarely, such as on shoulder straps, should be of a type that stays put under a load. Buckles on flaps and pockets should be of a type easily operated even with mittens, particularly if the pack is to be used in winter or at high altitudes.

The choice of leather or webbing for straps depends upon per­sonal preference and availability. Occasionally a very excellent grade of wide firm nylon webbing is available in surplus stores which can be tapered for the attachment of buckles. This web­bing makes very fine shoulder straps.

Where leather is used for pack straps the smooth skin side should be next to the shoulders because it is slippery, making the pack easier to put on and adjust properly. A heavy hard leather can be padded with a piece of thick spongy chrome tanned leather. The spongy leather is cut ¾"wider than the strap, to prevent the strap edges cutting into the shoulders under load. This construction is difficult for the amateur at home. A shoe­maker can do the job. He should use nylon thread since the straps are subject to abrasion. The two pieces can be glued as well as sewn for extra strength. Duco Cement may be used before the strap is taken to the shoemaker.

The zippers used in packs will almost always be subject to hard wear and are difficult to replace when worn out. For this reason die cast, size 5 Crown zippers should be used if at all possible. Care should be taken during the designing of the pack that no zipper is installed in such a way as to have any load applied across the closed zipper teeth. This is not because the zipper is apt to pull apart as cheap zippers on luggage will sometimes do—a size 5 Crown zipper is good for over 90 pounds per inch across the teeth—it is rather the fact that any zipper mounted across a line of stress is very difficult to close. It is also subject to damaged teeth in the process. It is also poor practice to install a zipper with a locking slider in such a manner that a pulling apart load can be applied to it when it is open or partly open. This puts the entire load on the few teeth engaged by the slider and may damage them.

As a good beginning project in the pack department the handy little belt pocket will give practice in both instructions and ma­terials handling. The stiffening band across the back makes it a bit better than the usual similar item available commercially. It makes a fine gadget bag for photographers. Score one in favor of making one's own equipment!

DAY PACKS

For the light loads carried on one day trips a frameless sack can be quite comfortable and light. Though the load is not heavy enough to warrant a frame, it is still a convenience and comfort if the pack is not allowed to lose its shape. About the only way to do this is by dividing the interior into several compartments. Partitions for the compartments prevent the gear from falling together in a heap in the bottom of the pack. They also make the pack convenient to use. Even a simple top and bottom division with conventional drawstring around the top and a zippered open­ing for access to the bottom is a great convenience and an improve­ment over a simple sack.

Plate IIIshows some features which may be helpful in design­ing small frameless packs. Fig. 4 is a design half way between a frameless pack and a frame rucksack. This has two long pockets from the peak where the shoulder straps are attached at the top down to the lower corners where the straps are attached at the bottom. Into these narrow pockets are inserted curved aluminum strips about ⅛" x ⅝" or ¾". These hold the pack away from the back and help it hold its shape.

WEEKENDER PACKS

The next larger size pack is the "weekender." Specifically, this pack must be large enough to carry a sleeping bag, a little food and possibly a tent. This, like the day pack, can be frameless, al­though in order to have enough room inside for a sleeping bag it is usually impossible to use any inside partitions to help hold the pack in shape. As we have said before the rucksack is fine for weekending. A weekend's supply of equipment can generally be kept well below the weight limit of this type of pack. Its comfort and convenience make it ideal for a pleasant weekend of hiking and climbing.
A removable frame on a rucksack has an advantage. It can be loaded to the limit with the frame in place for back packing into camp, and then used only partially loaded without frame for a comfortable day's hiking on short trips away from the base.

As a general rule it is best to consider a pack with the maximum load in mind and use it partially loaded for short trips and hikes, rather than to overload a small pack when a longer trip is planned. Overstuffing a pack makes the shape difficult and uncomfortable. Pockets are a great convenience in separating gear and keeping it where it is wanted.

There are several types of frames that can be made for this rucksack. A solid plastic frame will absolutely prevent the con­tents of the pack from poking through to the wearer's back. A panel of heavy nylon mesh bridged across the curvature of the frame, riveted at the corners, will bear comfortably against the back, distributing the force over the broadest possible area.

One of the best materials for this frame is fiberglas reinforced plastic of the type featured by many hobby shops for home work­ing. Glass fabric, rather than fiber mat, will make the strongest frame. The frame is constructed by making a sandwich of one tri­angular piece on each surface, two extra bands about 3" wide across the bottom, and an extra scrap in the peak between the full sized pieces. The frame must be made on a mold having a com­pound curve to fit the back. This can be made of cardboard, papier-mache, plaster, or an old automobile fender. Instructions for handling the plastic itself should be obtained from the supplier of the plastic.

There is available also a very tough rubber-like thermoplastic called Royalite which will become soft and sink into the shape of a dished mold placed under it at 300°F in an ordinary oven. This plastic at ⅛" thickness is slightly heavier than fiberglas but easier to handle. This material should be cut oversize as it shrinks dur­ing the heating about ½" per foot. (See Fig. 2, Plate IV.)

The simplest frame to make is with 7/32" diameter steel or aluminum rod with straps rather than a mesh panel to keep it away from the back. Details of construction for these are shown in Fig. 3, Plate IV.

There are several accessories which can be advantageous with this size weekender pack. Sponge rubber pads for the shoulder straps are wonderful for bony shoulders. These are made very neatly by wrapping a piece of nylon around a piece of sponge rubber. The nylon is wrapped around the rubber and lapped about ½inch in over the top side. It is secured to the rubber by stitching through around the edge. Two or three short pieces of webbing across the rubber under which the pack straps slip are included in the stitching. The advantage of this type of construc­tion is that the sticky rubber is left exposed where it is in contact with the shoulder straps thus holding the pads in position, while the side that goes against the shirt is slippery nylon which makes it easy to slip into the pack.

It is very difficult to sew sponge rubber on most sewing ma­chines. Heavy cotton thread must be used with an extra large needle. A ⅜" sponge rubber pad will do the job, but anything up to ¾" is better if it can be sewn. Since these pads are so small, hand sewing will probably be just as easy. (See Fig. 4, Plate IV.)

Most packs have drawstrings around the top providing for closure. In summer these are only a nuisance to tie and untie, but in cold weather it can be downright dangerous to remove a mitten to get into a pack. The same situation exists with clothing and sleeping bag drawstrings. A neat little drawstring clamp can be turned out of plastic or aluminum if a drill press is available. A piece of rod is first drilled almost as deep as it is long. This makes a case into which slides a length of smaller rod (the plunger) with a small compression spring behind it. Before inserting the spring, measure its length when fully compressed. Put a scrap of something in the hole of the case which will prevent the plunger's go­ing in any farther than the fully compressed spring would allow it. Drill a cross hole through the case and plunger. Put the spring back in the case and compress it with the plunger until the cross holes line up. Pull both ends of the drawstring through the cross holes in the same direction. Release the plunger and the draw­strings are held tight, press it and the clamp can be adjusted to any position. (See Fig. 5, Plate IV.)

A simple little clamp can be made from a piece of stiff leather or plastic for drawstrings which don't get such rough service, such as clothing drawstrings. Four holes are punched in a square of leather or plastic. When squeezed into a fold so the holes face each other the clamp slides easily, but when it flattens itself out it grips the cords. (See Fig. 6, Plate IV.)

One way to hold pack flaps down without the use of buckles which are difficult to work with mittens on is to run a cord through two grommets set in a piece of webbing as shown in Fig. 7, Plate IV. The webbing is sewn tightly to the pack and the friction of the cord passing behind it will hold the flap down. The cord should be long enough so the flap can be pulled com­pletely out of the way.
For mountain climbers there is the recurring problem of what to do with the ice axe when it is not in the hands. It is sometimes stuck head down in the pack, but this can be difficult in the middle of a cliff. A little leather gadget made and attached to the pack allows the ice axe to be snapped in and out at will even in the most difficult spots. A flap is sewn to a rectangular base of leather to take the pick of the axe. A suitable distance behind it a small snap loop of leather is sewn to go around the neck of the adz to hold it in position. This assembly is sewn to the lowest possible position on the back of the pack. As high as possible on the pack a leather holder for an accessory strap is sewn. Through this is inserted a short snap or buckle strap to go around the shaft of the axe. A similar type of carrier can be invented to hold tripods, fishing poles, or other ungainly but frequently needed items. (See Fig. 8, Plate IV.)

PACKBOARDS

In the domain of the packboard will be included all the sacks, even though some of them are only of weekend capacity, that use a packboard type of frame for their foundation. The sacks them­selves are constructed in the same manner as the rucksacks de­scribed before—using the same kinds of outside pockets, leather bottoms and other features. The major difference is that the pat­terns for these packs are generally easier to lay out because they are essentially rectangular. Since the straps are not always at­tached to the sack itself, the top edge and flap treatments are dif­ferent.

Most sacks are removable from the packboards so the boards themselves may be used alone for miscellaneous loads. Since the top edge of the sack must bear most of the weight, some thought must be given to its attachment to the top of the packboard. Small aluminum clips attached to the top edge of the back of the sack suitably reinforced, may be used. A strip of webbing should first be sewn across at this point extending around the corners on both sides to be included into the system used to close the top of the sack. These aluminum clips can be formed out of .050" 2024-T3 aluminum sheet. Do not try to bend the aluminum around a radius smaller than ⅛". If drawstrings and grommets are used around the top of the sack this effectively transfers most of the weight of the load from drawstring to webbing to clips to frame without putting undue strain on the pack fabric at any point.

Copper rivets and burrs are good to use for attaching the clips to the pack. At least four clips should be used.

Another method of attaching the sack to the frame which dis­tributes the strain well is to sew a wide leather flap to the top of the sack back. This flap is folded over the top edge of the frame and held with snaps, or permanently with rivets. See Fig. 1, Plate V, for various methods of attachment to the frame.

The sides of the sack may be held in line next to the frame less securely since they bear very little weight. It is a good idea, never­theless, to use broad tabs or flaps sewn to the sack side seams rather than several more localized points of attachment. Flaps with sev­eral grommets in them can be laced to the pack board sides or to each other across the back of the pack board as shown in Fig. 2, Plate V.

It is often a great advantage to have a relatively small sack for the packboard, and yet have provision for the expansion of the sack to full size when it is needed. One way to do this is to attach the sack somewhere short of the top edge of the board. By using an inside sleeve around the top of the pack, it can be pulled out and extended when needed and tucked down inside when the small sack is needed. The top of the sleeve has grommets and a drawstring just like the top of the sack. (See Fig. 3, Plate V.)

It is often useful to have a sack that can be used by itself with­out the pack board. In this case shoulder straps must be attached to the sack. These separate shoulder straps can be of the design used on a day pack or light rucksack and should usually be at­tached at the top, just below the arrangement for attachment to the pack board. A 6" square patch of fabric can be sewn on first lor general reinforcing. The straps should then be attached fol­lowing the same method as that described for the Zephyr Pack, using a leather cover patch over the strap ends with several rivets. The lower straps should be attached at a seam or point that offers a little reinforcement to spread the strain. If this is impossible, some extra fabric patches should be sewn on here for reinforcing also.

Since most pack board sacks are cut to fit a rectangular board they are not going to be quite as comfortable as a rucksack when used by themselves with their own straps. However, they can be made to double very nicely as a one-day pack provided they are never overloaded.

The pack boards themselves can be of more varied design than the sacks.  They can be made of wood, plastic, sheet aluminum, aluminum or steel rod, aluminum or magnesium tubing. They can be anything from a simple frame which holds the sack in shape to a large board with lashing hooks and a shelf at the bot­tom for carrying large and heavy loads of miscellaneous equip­ment. The support for the back may be anything from a canvas panel to string lacing. The important points to remember are:

1. The load is going to be supported against the entire back so the board must fit the back comfortably.

2.  The board should extend relatively high so the load will be placed over the legs with only a slight forward lean to the body.

3.  The lower shoulder straps should be attached as far to the rear of the board as possible so as to tend to throw the weight of the load forward onto the back. The upper shoulder straps should be as broad as possible to distribute the load over as wide an area as possible. (See Fig. 8, Plate V.)

4.  If the board is to be used mostly for miscellaneous loads it should have a convenient lashing arrangement. (See Fig. 10, Plate V.)

Many pack boards, such as the Yukon and the Trapper Nelson, have been made of wood in the past. This is still possibly the simplest material to work with but it won't produce a strong board that is really light. Even the molded plywood board of the army, which is beyond the ability of most amateurs to make, is heavier than need be, though quite durable for army use. Fiber­glas reinforced plastic can be used to advantage here. The ad­vantages of fiberglas are its solid surface which prevents any of the load from poking through to the back, and its durability and light weight. Provision for hooks or other fixtures for attaching the lash rope is often a problem that discourages plastic for a large size pack board. Some type of hook riveted on would be the easi­est construction. An edge reinforced with metal rod with the plastic cut back from the rod at intervals, though sturdier, would require the lash rope to be threaded through each time it is used. This arrangement would be much better where the pack board is to be used for tough going through heavy brush where almost any kind of hook tends to catch in every small branch as it brushes past.

Sheet aluminum is heavier than fiberglas and generally less sat­isfactory although it is easier to fabricate and therefore might merit consideration.

Almost all the better commercial pack boards are made of tub­ing, either aluminum or magnesium. For the slight additional difficulty of fabrication, the magnesium seems well worth the ef­fort to achieve the ultimate in a light weight board. Reynolds aluminum tubing however is now available in most hardware stores. Magnesium is hard to find. Both aluminum and mag­nesium are difficult to weld and not every welding shop can do a good job. A good idea is to let the prospective welder do a few sample Tee joints. Then break them apart with a hammer to see if he can do a satisfactory job. Undoubtedly a good man with a Heli-Arc outfit can do the highest quality welds on these metals. If a good riveted design can be worked out it will eliminate the soft annealed spots in the frame that result from the welding.
The lightest weight board is one of simple ladder design with curved rungs and side pieces, either straight or with an S curve to fit the back, made of ½" magnesium tubing. Light weight has its price, however. No lashing hooks are provided, and this curved skeleton frame is not the easiest for comfortable attachment of odd shaped loads. Some sort of bracing must be provided for the cross piece that carries the upper shoulder strap attachment, except on boards designed for the lightest loads. This bracing can be ex­panded to help close up the wide open spaces left between the cross pieces. The need for closing up these spaces is greatest at the bot­tom of the frame and least near the top. Lashing hooks can be provided by welding pieces of rod shaped into hooks directly to the side members of the frame.  (See Fig. 10, Plate V.)

There is no doubt that tubing will make the lightest, most rigid pack board, but it does have disadvantages. If a disaster befalls the pack, such as a fall over a cliff, or a pack animal losing its load, in which the frame becomes bent it is usually impossible to straighten it. Tubing of thin wall section will cave in when bent very far and will break when straightened.

Solid rod, if it is properly welded will make a board that can be bent into a pretzel and still be pounded back into shape. This feature is well worth considering for heavy expedition work. By using a solid rod having a spring temper it is possible to design a flexible frame that will take a lot of abuse without permanent damage. The use of rod is also very convenient in some minor details such as forming lashing hooks as an integral part of the frame. Rod also lends itself well to the design of a frame with a flat cargo surface with plenty of depth at the bottom. The flat cargo surface is much more convenient than most other arrangements for attaching loads. Because of these features, the solid rod construction is recommended for pack boards. However, it is rec­ognized that with pains and skill a superior board may often be custom made out of other materials.

Aluminum rod can be used for this type of construction but it must be remembered that welding will anneal the rod and the smaller diameter of the rod as compared to tubing will allow it to bend much more easily in these places. A spring tempered steel rod of 7/32" diameter will weigh little more than a good rugged aluminum tubing. Cold drawn 18-8 stainless steel rod is ideal in all respects, although ordinary cold rolled rod will do.

Steel will be annealed in the welding but its greater inherent strength will eliminate the bending if care is taken in the design and no welds are put in the middle of the cross pieces. In the sketch of the suggested design for this type of board there are no welds where the brace carrying the shoulder straps run parallel to the cross piece, nor where the bottom curved brace and shelf ex­tension cross over the cross piece. The only welds are on the sides. Note also the ease with which the lashing hooks are formed on the ends of the crosspieces. They are curved until the ends are actual­ly inside the frame to avoid catching branches. Most pack boards can use a narrow shelf across the bottom. This keeps the load from slipping down under constant bouncing.
The depth at the bottom of the frame is a very important com­fort consideration with very heavy loads, Most of the boards dis­cussed previously will have to depend on a panel, or band laced across the curvature of the frame to support the load on the back. This means that the contact with the back is limited to the curva­ture formed by the push of the load against the tightly laced panel or band. With a deep frame, one that comes half way around the body, it is possible to use a curved band, as on a rucksack frame, that contacts the entire curve of the back from side to side. This distributes the load over a much wider area and gives the board greater stability due to its body-hugging features. (See Fig. 11, Plate V.)

Unfortunately however, if the lower shoulder straps are at­tached to these forward corners of the deep frames, as is so often the case with rucksacks, the shift in this critical pivot point will tend to make the pack fall away from the back thus defeating the advantage of the pack board. If the frame has depth at the bottom to allow a comfortably curved support band, then it must have some point well to the rear for the attachment of the lower straps. (See Fig. 9, Plate V.)

It should be pointed out here that a board which curves over the head allowing the load to be placed high and forward over the legs is very good for trails and general hiking. For mountain climbing however, as we have said, it is often necessary to look up to see the route and bumping the head on this forward portion of the pack board can become a nuisance. Its high center of gravity is a disadvantage on rough terrain.

For the ultimate in comfort a pack board should be made to fit the body of the person using it. It should be wide enough to reach around the hips but not so wide that the elbows hit it. Its height should be as great as consistent with the use to which it will be put. Remember to secure a place for attaching the upper shoulder straps as determined by the method described at the beginning of the chapter.  The depth at the bottom should be about 4".

The actual attachment of straps to the pack board merits care­ful consideration. The lower straps can be ¾" webbing or leather. They should attach as far to the rear as possible so the load will be tipped against the back. This rearward attachment sometimes makes it difficult to slip into the pack. This can be solved by inserting a snap hook and dee ring arrangement to allow the straps to be opened while the pack is slipped on.
In the case of the solid rod frame suggested, the straps may be riveted loosely around the bottom rod so they can be slipped for­ward for getting into the harness and then slipped to the rear corners after the board is on the back.

Since the pack board is designed to carry maximum weight the best and firmest leather or web should be used for the upper shoulder straps—at least 2½" wide. A wide padded strap similar to those used on the smaller packs but with more padded area can be used. It is possible to fasten the straps directly to the frame but it is more comfortable if a leather yoke, cut to fit close to the neck and over the shoulders, is used to locate the straps definitely on the body as illustrated by Fig. 8, Plate V. If the straps are attached separately to the frame they should be held close to one another where they leave the frame so they pass close on either side of the neck. If they bear too far out on the shoulders the leverage exerted will be very tiring on neck and shoulder muscles.

Last we come to the method of supporting the frame and load against the back. The simplest method is the use of a canvas panel, the full size of the frame up to the shoulder straps, wrapped around the frame and laced together at the back. This helps to close the open areas of the frame and is the usual method used with wood pack boards. As mentioned before, this panel is hot and heavy. A panel of heavy nylon mesh laced to the sides of a tubular or solid rod frame is relatively cool and saves considerable weight. This nylon mesh panel is sewn to the leather band at the bottom of the board.

The heaviest part of the bearing weight comes at the bottom of the board. A heavy leather, or other firm material, band at least 3" wide is a good idea at this point. This should be adjustable by passing the leather around the edges of the frame and lacing it together behind. The lightest frames can use another similar but lighter band about half way up the frame. The two bands are also cool but may not give great enough distribution of weight to be comfortable under heavy loads.

One excellent method of supporting the frame that is tradition­ally applied to Trapper Nelson boards by knowing users is the string lacing. This consists of light cord laced back and forth through holes drilled about 1" apart along the edges of the board. This gives light weight and very cool support, but is not good for the heaviest loads.
The subject of packs is almost inexhaustible. Their design can be as personal as a well tailored suit. With thought and care put into the design the pack will reward its owner many times over.  His back will really know the difference!

There are two heavy load pack accessories commonly over­looked, which can give a good deal of added comfort. One of these is the waist strap. The use of this strap is primarily to snug the load in close against the body rather than to carry any of the load on the waist. This closeness transfers some of the load onto the slope of the buttocks where it is more easily carried than on the shoulders. The second accessory is the tumpline. This is a wide pad or band which goes over the forehead and is attached to the pack with two lines which hook onto two tails sewn on the pack for this purpose. These tails are attached to the pack far to the rear and low down. When this tumpline is properly adjusted, the head can be put into it every so often for a few minutes, re­lieving the shoulders of their load completely. With a heavy load on a long hike this is a great comfort.

Belt Pocket

List of Materials

Fabric—6" of 44" or 30" wide
2" Web—7"; or 7" x 2" piece of heavy leather
¾"Web— ll½"; or 8½" of ¾" leather
Zipper—one 8" pocket style, or open top

Instructions

1.  Read "Layout and Sewing" to familiarize yourself with operations and terms used.

2.  Lay out and cut parts, piecing no. 3 Gusset if necessary as indicated for 30" fabric. Allow ⅜" extra on each piece for rough flat felled piecing seam. All other seam allowances are included in the dimensions.

3.  Sew zipper into slit in no. 3 Gusset with leather or web pull tabs at the ends.

4. Cut parts no. 4 and no. 5 of web or leather.

5.  Place parts no. 5 across part no. 4 about 1¼" in from each end. Tuck ends around edge of no. 4 and stitch close to edge to hold
in position.

6.  Sew assembly as prepared in step 5 across the top of no. 2 Back, ¾" down from edge.

7.  If you want to add any inside pockets or loops of elastic to hold specific camera accessories or first aid supplies, etc., now is the time to do it. Sew them to the insides of no. 1 Front or no. 2 Back.

8.  Starting at the bottom center marks, sew edge of no. 3 Gusset around edge of no. 2 Back with a plain seam ¼" in from edge.
Use seam binding tape if desired.  Repeat with other edge around no. 1 Front and turn right side out.
Echo Pack

List of Materials

Fabric—4 1" of 44" wide or 62" of 30" wide
¾" Webbing—9 feet, or ¾" leather strap—9 feet
Nylon Cord—8 feet
1½" Webbing—3 feet, or 2" leather strap—3 feet
Heavy Leather—5" x 7" for strap end cover piece and 4 accessory strap holders
Soft Leather—16" x 17" for leather bottom, or this may be of same fabric as pack, in which case increase fabric by 1 foot. Double bottom is optional but advised. Buckles—2, for ¾" strap
Snap Hooks—2, optional for use in shoulder straps, ¾"Dee Rings—2, optional for use in shoulder straps, ¾" Strap Tips—4, for ¾" strap
Grommets—18, size no. 1 Zippers—2, 12" long, pocket style or open top

Instructions

1.  Read "Layout and Sewing" to familiarize yourself with the terms and operations used.

2.  Lay out and cut parts. Be sure to include 2 each of parts no. 3 and no. 4.  Cut second part no. 5 Bottom either of fabric or soft leather and enough of the same material l½" wide to run across the bottom edge of part no. 1 Body. Mark position for pockets, etc., on right side of fabric.3.  Sew zippers into slits on parts no. 3 Gussets with leather or web pull tabs at the ends if desired.

4.  Join ends of parts no, 3 with a plain seam to form a loop. Then, starting with this seam at the bottom center mark of part no. 4 Pocket, sew the edge of part no. 3 that is farthest from the zipper, around the edge of part no. 4. Use a plain seam with seam binding tape if desired and adjust parts as necessary so top center marks coincide.

5. Sew the pockets to part no. 1 Body at location marked. Use a top stitch seam. Start with bottom center key mark and seam in Gusset no. 3 even and adjust so top center marks also coincide.

6. Cut two 15" lengths of ¾" web or leather. Cut slits ½"long for grommets as indicated on part no. 7 and set grommets. Sew these to part no. 1 alongside pockets as indicated. Start with end B at bottom of part no. 1 and sew up one edge and down the other. Turn top under if web is used. Be careful when sewing around the grommets. It may be necessary to hold the material down with a screwdriver when the machine presser foot is up on the grommet to make it stitch.
7.  Sew 1½" wide strip of leather or fabric, whichever is being used for bottom, across bottom edge of part no. 1 Body, as indicated.

8.  Cut two Accessory Strap Holders, part no. 8, from the heavy leather and sew below and forward of each side pocket as indicated.

9.  Sew edges of part no. 2 Back to edges of part no. 1 Body with a flat felled seam; finished felled seam if fabric is light enough.

10. If no snap hooks are used in the shoulder straps, cut 2 pieces of ¾" web or leather 15" long. Tip both ends if web is used. Sew to outside of part no. 2 at locations A and B. See detail Fig. 1, except that instead of a buckle, the upper end is 12" long, and will attach to the buckle of the upper shoulder strap. If snap hooks are used in the shoulder straps, proceed as follows: cut 2 6" lengths of ¾" web or leather. Tip one end if webbing is used. Sew onto outside of part no. 2 at locations A and B including a buckle. See detail drawing Fig. 1. The extended tab is to be used in attaching the sack to a frame and will be fitted with hatever hardware is needed later. These tabs will accommodate a frame 18" wide. If a different size is needed this is the time to adjust the tab length. If no frame is to be used the tabs can be omitted, or they can be used as a waist strap if they are made longer.

11. Hem around the top of the sack with a plain hem that finishes ¾" wide. Fold this against the inside of the sack. Set grommets as indicated on drawings of parts no. 1 and no. 2.

12. Sew the two parts no. 5 Bottom together with a vee of stitching as indicated.

13. Sew the bottom into the pack with a plain seam. Use binding tape if desired. Start with bottom center mark part no. 2 on mark A part no. 5 and adjust so mark B part no. 5 falls on bottom center mark part no. 1.

14. Sew trim web to part no. 6 Flap on outside as indicated.

15. Box rear corners of Flap at marks as indicated in detail draw­ing, Fig. 2. Sew a plain hem around edge of flap about ¾"wide. Set two grommets in ends of trim web.

16. Sew flap to sack at top of part no. 2-on line marked. Stitch back and forth several times at ends. Center flap on the marked line.

17. Prepare web or leather shoulder straps 1½" to 2" wide and 18" long. Cut taper in leather or sew taper in web. If snap hooks are not used attach buckles. If snap hooks are used attach dee rings to ends. Cut other end to shape approximately as shown in detail drawing Fig. 3. Cut two more accessory strap holders and sew to outside of shoulder straps 2" from end. Sew onto sack over flap and with edges of straps just above flap hem as in Fig. 3. Center straps between flap corners.

18. Cut cover patch of heavy leather and sew on as shown in Fig. 4. The bottom is left open to receive the top of a frame if one is to be used, otherwise it can be sewn closed too.

19. Omit this step if snap hooks and dee rings are not used in the shoulder straps. Cut two lengths of ¾" web or leather 12" long. If web, set tips in one end. Rivet a snap hook on the other end and attach to lower shoulder buckles. Snap hook into upper shoulder dee rings,

20. Set rivets as follows:
4 in shoulder straps as in Fig. 4
8 in accessory strap holders as in Part no. 8 drawing
2 in lower shoulder straps as in Fig. 1

21. Cut two pieces of nylon cord 24" long and one 48" long. Thread the 48" piece around top grommets for a draw cord and knot the ends. Tie the ends of the 24" cords to the flap grommets and thread the other ends in the top friction grommet and out the lower one. A large crochet hook no. 00 is good for this.  Knot the ends to keep the cords from pulling back through the friction grommets. This will provide enough friction to hold the flap closed yet it can be opened by simply pulling it back.

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