Tandem kayak in 2 halves

[Michel JAN]

Anybody there with building experience of a hard chine plywood tandem kayak, assembled in
2 parts, for easy stowing, in 11' 6" maximum length. The assembly could rely on bolts in the
middle, through a central hatch. Will the assembly be strong enough?

[mmd]

Contact Gerry Gladwin and ask him about his Volkskayaks. He sells kits, teaches how to build, etc. and has several models of modular kayaks. Nice guy , too.

Gerry Gladwin
Whynot Boats
PO Box 1074
Wolfville, NS B0P 1X0
902-542-3244

www.volkskayak.com

[LeeG]

http://www.kayakforum.com/cgi-bin/Building/index.cgi

this is where you'll find builders of kayaks with immediate feedback by users of kayaks.

[LeeG]

The assembly could rely on bolts in the
middle, through a central hatch. Will the assembly be strong enough?[/QB][/QUOTE]

yes, if done right.

[Todd Bradshaw]

If I was going to do this, I'd split it into three sections. That way you can have a central cockpit portion and separate sealed bow and stern chambers.

[Michel JAN]

Thanks for the updates.
Todd, you are right. As I want a double, I am thinking about a central sealed chamber with a hatch, with the 2 parts being bolted in the middle of this chamber. This will be convenient for cartopping also. The kayak length being around 21' long.
Michel.

[LeeG]

Michel, I've paddled a few doubles, teach sea kayaking and watched them being designed at CLC.
I'd go for two pieces simply because transporting 3 sections on the roof of a car is more problematic than 2, I assume the need is for storage in the garage that's less than 21' feet long? Have you paddled doubles and determined an acceptable cockpit to cockpit distance? While the idea of an airtight center bulkhead is a good one from a flotation standpoint compared to none the amount of water a double can take on is huge, and requires extraordinary measures compared to a single in waves. What kind of displacement are you looking for? Wilderness Systems NorthStar Pro is a good volume for an all around double, once these 30" wide doubles get upwards of 21' they can conceivably carry 750lbs which is ridiculous for human power in rough conditions. One of the good things about making your own kayak is that you can put the forward bulkhead on either cockpit as close to your feet as you want as it's your boat. Most commercial kayaks have enough room for a 6'6" person which is about an extra 200lbs of water per cockpit if the bulkhead is a foot away from the footbraces. If you don't need a huge range of footbrace adjustments consider getting Yakima aluminum footbraces, cutting them in half, 7", which will give about 3" total adjustment which is enough for one person to be happy.

[Ian McColgin]

I'd love to more about doubles in general as I've not been in one in about 25 years.

Tried two different types - one had the cockpits fairly far apart bulkhead between and the other had them closer. Neither had two bulkheads between to make a watertight space in the middle. Both had bulkheads fore and aft.

I saw no advantage to much space between the cockpits. Having my partner's butt about at my ankles was as far apart as we liked.

With the greater spacing, we'd sometimes attempt a roll up with me doing a right and roll and her a left. With the closer spacing I could always feel which way she was going.

The long seating with bulkhead gave no new bouyance and, having two full size cockpits, actually allowed more water in the boat if the skirts pushed in.

Being close was not at all a problem with coordination if the stern paddler is at least half good. Anyway, a proper stroke enters the water about where your ankles are and ends a bit abaft your butt, so with the closeness we used to like, any paddle tangle would take a fairly huge out of synch problem - it never happened.

I think that a two holer is connected between the cockpits, no bulkheads and good access to the latches that pull stuff in. It's a good place to work in the little bit of extra framing the connection takes.

I used to think of a one long holer - especially possible now with improved skirt materials - so that it would be easy to jog the aft seat ahead a bit when paddeling solo. That also makes standing up far easier. Standing in the boat has huge uses - poling up river, looking around, and showing off.

Whatever.

G'luck.

[LeeG]

In order to save weight (a double can get heavy and the associated take apart hardware will add weight) consider not using glass tape as much as everyone uses it in S&G. It doesn't often lay flat, the selvaged edge is a bother, since a double will need interior cockpit bottom glass at least it'll go on before the tape or the tape will require major finishing for the cloth to lay on it, bias cut 6oz probably has the same strength as regular tape although I've never done destructive testing. Pre-glassing the interior panels before stitching is one way to controll excessive epoxy use with a followup fill coat used to apply cut cloth as needed. Again check out Guillemots forum, I'm pretty sure there a couple takeaparts that can be found. Unless you HAD to have a 21' boat and need a 500lb+ capacity hull you might check out Eric Schades Eider double and turn it into a TAP.