Tom Yost Designs

TDY-16 Design 2002

In order to save weight, TDY-16 is built using 3/4in X 0.035 tubing. In addition, there are 6 HDPE cross sections (FAP-16 has seven). The HDPE stem/stern use lightening holes, and the coaming will be light weight fiberglass. The frame, without coaming, weighs 13.5lbs. Completed weight with 13oz. PVC skin material should be approx. 25 lbs.

LOA - 16ft.
Beam - 23in.
Weight - 25 lbs.
Stringers - Aluminum 3/4in. X .035 Walls
Skin - PVC

This Non-Aleut design is intended as a lightweight medium volume touring kayak. As compared to FAP-16, it features a peaked deck to improve interior room for the paddler as well as more storage space. It utilizes thinner walled tubing (3/4" X .035) and six cross sections ( FAP-16 has seven) to reduce weight. The cross sections, coaming, and footbrace are made from HDPE. Finished weight is approx. 26 lbs.

The skin is a sewn, one-piece Polyester (9 oz.) design, and is coated with Neoprene/Hypalon. The hull is covered with eight coats of neoprene, while the deck is covered with five coats neoprene and three coats Hypalon. Neoprene is a bit easier to apply than Hypalon. It cures quicker, and is more durable. Hypalon has the advantage of being easier to fold, and is available in many different colors.

The following pages highlight only those construction details not included with, or that differ from FAP-16:

Stem, Stern and Frame
FAP-16 and TDY-16 Frames
TDY-16 Frame

Coaming Details
The HDPE coaming is comprised of 1/4" baseplate, 1/2" coaming, and 1/8" coaming lip. Machine screws are used to provide a secure coaming attachment.

Polyester Skin (9oz.)
The one-piece Polyester skin is sewn with nylon squidding line. The deckridge and stem/stern are cut (seared) with a propane cutting blade prior to sewing. This process assures a hard edge that will not separate. The deckridge will be cut open for the installation of lacing or zippers.

Neoprene
The frame is first waxed to insure that neoprene will not soak through and stick to either the aluminum or HDPE. Before coating , a heat gun is used to remove wrinkles still remaining in the skin after sewing. The first two coats of Neoprene are thinned with 10percent Zylene to insure that the neoprene will soak deeply into the polyester cloth. Subsequent coats are thinned but to a lesser degree.

Neoprene is applied with a 3 or 4 inch brush. Use short brush strokes and be sure not to brush the neoprene once it starts to glaze over. That will cause ripples in the surface. Maintain a wet edge and move quickly along the surface. Subsequent coats of neoprene can be applied every 30 minutes or so.

When the skin is removed, the inside hull will receive 2 additional neoprene coats. This is not necessary, but will insure complete saturation, and makes for a better looking job.

Always wear a respirator, and work in a VERY well ventilated area.

Hypalon
After applying neoprene, the deck or hull can be coated with additional Hypalon to give it a color other than black. Hypalon cures slower than neoprene and requires a longer wait between coats. Hypalon stays slightly tacky for a few weeks. Adding Lacing, zippers, flaps, and deck rigging can be done in a week or so after coating. Wait several weeks after coating before removing the skin. I normally wait a couple of months before folding the skin.

The main advantage of the Polyester/Neoprene/Hypalon skins are their one-piece construction and ease of repair. An additional coat of Neoprene/Hypalon every couple of years will keep it looking like new.

Rub strips can be glued to the keel and chines for added durability.

Skin/Coaming Attachment
On FAP-16, the skin to coaming attachment is accomplished by wrapping the skin under the baseplate and using snap connectors.

On TDY-16, the skin is attached directly under the coaming with machine screws and recessed snap connectors. This is a cleaner installation, but the other method is easier.

Finish
At this stage, all that is left is to install lacing or zippers, attach the flap, and deck rigging. The seat is a gunwale mounted sling type similar to that in FAP-16. A paddling report will be added later.

FAP-15 Design 2002

Based on FAP-16, this smaller/wider version was designed to use the minimum of materials possible while still producing a lightweight, strong, and durable folding kayak. This has been accomplished by using (5/8" X .049) tubing in place of the normal 3/4", and also by having only four cross sections, instead of FAP-16's seven. The displacement figure of 190lbs is at the 4.5" waterline. Final displacement at the gunwales is in excess of 600lbs. The finished kayak weighs about 24lbs.

The cross sections, backrest and footbrace are made of HDPE. The skin is a sewn, one-piece Polyester design. Coating are Neoprene/Hypalon.

The deckridge is considerably taller than FAP-16 to provide greater room for comfort and storage. Personally, I prefer lower, flatter decks, but wanted to provide an alternative for other builders. This Aleut based frame is made of 5/8" tubing. Though flexible, it showed no signs of deflection in the water. The HDPE cross sections allow for ease of construction and assembly. The tubing size and number of cross sections are the same as the Feathercraft Kahuna (14'6" LOA). Tubing size can be changed to 3/4" if desired during construction.

FAP-16 Design 2002 (TDY)

The design goals for FAP-16 were to make the kayak easy to build (Under 100 hrs.), Easy to Assemble (Under 30 Min.), and light weight (under 40lbs). Above all, Tom wanted this boat to perform as well as any non folding skin kayak.

LOA - 15ft. 8in.
Beam - 23in.
Weight - 35 lbs.
Stringers - Aluminum 3/4in. X .049 Walls
Skin - Polyester/Hypalon

BIF Design 2002 (TDY)

This kayak is loosely based on the CNM-12212 single chine Aleut design Tom has built some time ago. It is very fast for a 16ft kayak and is much more stable than it looks. With 28deg deadrise and very generous rocker, it tracks beautifully but can carve a quick turn. It compares favorably with his Lowie Museum LM2-14886 in stability and turning, but is faster. This will make a great workout boat.

LOA - 16ft 2in.
Beam - 20.5
Weight - 25lbs.
Construction Time - 75hrs.

CNM Design 2001 (TDY)

Tom writes:

I've just recently completed a new kayak after a few years inactivity. The design is a hard-chine Iqyax (CNM-12212) that I built based on a simplified version of George Dyson's method utilizing aluminum stringers with plywood cross-sections. The skin is 8oz nylon coated with several coats of neoprene/hypalon.

Length - 17.5 ft
Width - 17.5 in
Weight - 28 lbs.
Cp - .61

With 33 degrees of deadrise and very generous rocker, it is visually very interesting and has great performance to match. It lays on it's side up to the gunwales when resting unoccupied on the water. Seems to support the Veniaminov and Sauer accounts of the Iqyax form.

Various Designs (TDY)

Tom has built more than 20 boats since 1975, with the first eight being woodstrip/fiberglass sea kayaks. Of that group, two have been Aleut designs constructed from David Zimmerly's offsets in his book "QAJAQ". He built them to scale but made changes to the deck shape. In addition, Tom built a woodstrip version of George Dysons double.

Having grown a bit tired of building woodstrips, he decided to try a hand at non folding skin boats. He first made three George Dyson singles, the first two of all wood construction, and the third using wood cross sections with aluminum stringers.

He immediately realized that these were more seaworthy than were the woodstrip hulls. The flex in the skin and the concave skin shape between stringers, really slowed down the roll rate as well as allowing the hull to conform to the waves.

The first folder that Tom has made, about 1993 or 94, is a folding wooden (pine) version of a Dyson single. Skin is Nylon/Neoprene/Hypalon. Time to assemble - Forever !

His second folder was an Aluminum/Wood Dyson Double (1996).
Third was an Aluminum/Wood single (1997).
Fourth was an Aluminum/HDPE single- FAP-16(2002)
Fifth is an Aluminum/HDPE single - TDY-16(2002).
Sixth is an Aluminum/HDPE single - TDY-15(2002).

Above is a photo of the folding single that Tom was building 1998(?). You will notice a striking similarity to the "Feathercraft" designs. Since he paddles a Feathercraft K-Light, the similarity is no accident. You will also notice that there are very few parts. This boat follows the KISS principal. ( Keep It Simple Stupid)!

The tubing is all 3/4 in. Aluminum 6061/T6 thin wall. The tubes are attached to the Cross sections using "L" shaped brackets pop riveted to the tubes. The frame weighs about 15 lbs and takes only a few minutes to assemble. The frame has a single stretcher bar at the keel. The skin will be made of 14 oz. pre-shrunk nylon. The material will be coated inside and out with three coats of black Neoprene. The deck will receive additional coats of white hypalon to provide a light color. The boat is 15.5 ft (4.73m) long by 24 in. (61cm) wide.

Tom plans to use zippers along the deck ridge for closure and sewn in sponsons to assure a tight fit and to provide additional stability. At least in my case, the zipper/sponsons solution has worked more than once. Just take care.

They keep getting lighter, easier to build, and quicker to assemble.

SPY-10 Folding Sailrig (TDY, Oct 2002)

This sailrig is designed for use with FAP-16. It can be adapted to other folding kayaks with minor modifications. The amas are constructed using aluminum tubing, HDPE Cross sections, and a nylon/neoprene skin.

This ama design is based on, but not a copy of, the Chesapeake Light Craft Eight Footers that appear in Woodenboats #131, July/August, 1996. The CLC amas are made of plywood and feature a "V" shape cross section. The SPY-10 folding ama utilizes aluminum tubing with a nylon/neoprene skin. The cross sections are "Hard-Chine". The amas are 10 feet long to approximate other designs currently in use.

With 3 cross section and 3/4"X.035 tubing, the amas weigh 7lbs. each. Estimated weight with Nylon/Neoprene skin is approx. 10lbs. each. The 120lb. displacement figure is at point of submersion. The twin 10 foot akas are made of 1.5"X.049 tubing and break down into three sections. The center section is 4 feet, and the outer sections are 3 feet each.

There are two 27" inserts per aka, which are made of 1-3/8"X.058 tubing. The akas are spaced six feet apart as Tom felt that was a minimum distance for paddle clearance.

Tom's workshop is pushed nearly to it's limit when the sailrig is assembled.