F1 technical details

Deciding to put this info online was a hard choice for me.  I've always believed in open source design but I have to admit I'm a little afraid that someone commercial will steal my design work.  I also don't want to lose business to people who might have otherwise taken a class, however, I have to believe that anyone who can take a class will come take one, after all, this drawing just gives you a shape, not the easy, efficient system I use to make the kayak.  So, to be clear, the information presented here is for the people who could never make it to a class, or have already taken a class to build for themselves only.   This kayak represents thousands of hours testing and prototyping, please respect my design work.  More than two personal reproductions are forbidden, any reproduction for money or trade goods is forbidden.

My second issue is that I don't want people to build this kayak wrong and then call it my design.  Unlike other sea kayak I've designed, even small deviations from the above shape will yield poor results.  For example, I discovered that if the little 1/2" secondary chine is carried past the cockpit it messes up the surfing.  If you want this boat to paddle right you MUST follow the lines of the drawing.  That means that at any point during the process if you notice a measurement is off, stop and fix it!  Of critical importance is the waterline shape.  The first four ribs are extremely Vee'd, the next few are rounded, and the rest are progressively more squarish.  You'll probably have to crack the first four mortises to get enough Vee in the bow.  If you don't do this the boat will be slow and sluggish.   Ribs may need to touch the skin to get the shape in the stern.  The stern is critical, if the chines are not almost breaking when you tie them in, you are not forcing them high enough.  I cannot stress enough how important it is to be exact to the drawing.  The bow waterline must be very fine, and the the stern volume must sweep up out of the water leaving the "skeg" hanging down.

Third, I am not running an online kayak consulting business.  I already have more work than I can possibly do day to day.  Feel free to work from this info, but please keep inquiries to a minimum.




Here is a survey drawing of the F1 by Harvey Golden.  You should be able to enlarge the above drawing in a photo editing program and print it to a size that will allow you to take the dimensions straight off of the drawings.   I do this all the time with 8 x10 inch drawings of Greenland kayaks and rarely work from full size drawings.  Also, the aft deck beam on the new F1's is flat. Depth to sheer is listed on this drawing as 9 1/8 inches,  that should be more like 8 1/2 inches,  measured from the top of the gunwales to the bottom of the keel behind the cockpit.




The above drawing was provided to me by a brilliant engineering professor, Hung N. who was a student in one of my classes.   I noticed that the cockpit appeared out of place in relation to the ribs.   The rib behind the cockpit should be shifted forward so the forward edge of that rib is 3 inches forward of the forward edge of the backrest deck beam.    Also the bow rocker is a bit off,  but just a bit.   When building this boat use the above drawing as a guide but defer to the H. Golden survey for absolute measurements.    Below is a drawing created by cad drafter Rob H.  to show the difference between the two.




The cockpit as drawn is a bit too oval, it must be shaped more like an acute triangle to get somewhere to put your knees. 

Wilderness system slidelock footbraces are are installed.  I sit on a double thick foam mat.  The kayak is designed around a set of super tough cargo/float bags available from Spirit Line.

The leather straps are 3/8 strips of oil tanned latigo tied through the gunwales.  Every strap on the boat is strong enough to carry or tow by.

The rub strip at the tail is 1/4x1/2 brass or HDPE.

Gunwale angle is 25 degrees.

Gunwales are 14' long red cedar
(use 5/8 thickness for gunwales and stringers if using pine, fir, yellow cedar, spruce, ect.)
Stringers are 13'6" red cedar
Knuckle chine is red cedar
Stems are 5/8 x 5 1/2 x 24" red cedar
Deck ridge is 1 1/2 x 3/4 red cedar
Aft deck stringers are 7/16 x 1 1/2 x 18 1/2" ash
Ribs are bamboo spaced at 6" (make ribs 1" wide)  If using another bending wood (oak, ash) make them 1 1/4 wide
First three deck beams are four layer laminations of red cedar to 3/4" thickness x 1 5/8" wide
Last two deck beams are 3/4 x 1 5/8" red cedar
The coaming is 3/8 x 1 1/4" white oak
The coaming lip is 1/2 x 1/2" white oak nailed on with 3/4"  bronze ring nails every 2"  to hold a sea sock make it 3/4"

For people 220-250 lbs add 1/2" depth, 1/2" width
For people lighter than 135 lbs, subtract 1/2" width 1/2" depth

For a 31" inseam or below the cockpit should be 30" ID
For 32" inseam or above the cockpit should be 31 1/2" ID

If you build this kayak right it should turn like it has a rudder with body leans only.  You can increase this effect by raising the "skeg" in the stern by 3/4" making the boat very playful, but at the cost of tracking in a quartering sea.  I know this is hard to believe from a 14ft kayak, but it should be FAST.  Due to the very efficient hull shape it should cruise easily alongside much longer boats with less effort, up to 4mph.  It will also surf on any tiny (or big) wave with just a little bit of a shove to get it going.  When the shape is dialed in this is the best rough water sea kayak you will ever paddle, well except maybe for it's primary design influence, the Mariner coaster.   
If you build this boat and you like it,  please consider donating some money to me to fund more open source design work.  You can paypal me whatever you think is fair at: capefalconkayak@gmail.com      Good luck, have fun.


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