Skin on Frame Hatches

Here are some details of the hatch setup I put in my new kayak. Its my own design, and man was there a lot of futzing while I figured things out.

This first shot shows the frame assembly, its basically two glue-lam rings that nest. I just cut out a couple ovals out of MDF and wrapped it with 2mm spruce strips. The inner ring has a few extra strips added to make a large flange on top, as well as a thick center stringer on the off chance that my split deck stringers fail and the hatch gets subjected to compression force. Dimensions are 8x10" for the opening. I tapered the inner ring so it would locate easier into the outer. The extra line of holes was from an early plan to fully wrap the hatch with fabric, which would have messed with the clearance.

Sewing the hatch, the first attempt I wrapped the fabric over the ring, and down the hole, it resulted in some serious clearance issues, so here I am just saddle stitching it to the side of the ring. Later it will be trimmed, rolled over, and whip stitched.

I covered the hatch with the same skin as the hull, you get some wrinkles on the underside of the flange, but it doesn't matter as they will be hidden by the gasket.

I trimmed the fabric on the hatch flush with the inner corner. You have to watch out for any large ripples as they may affect the clearance with the inner ring. I ended up using a soldering iron to melt down a few lumps that got in the way.

This is the finished hatch in its open state. The gasket material is EPDM rubber weatherstripping(the same stuff as car door seals). I put one strip on the hatch, and a second on the rim just for extra water tightness. I first tried closed cell foam weatherstripping, but found it took too much force to compress and didn't give a satisfactory seal, it also made the hatch look like an inverse Oreo. You can also see that I put on a latigo idiot strap so I wont lose my hatch at the beach.

And the hatch closed and secured. I used two latigo strap loops, one on each side, each has a slider, and one has a toggle. Its set up so that you can just barely loop the strap over the toggle. If you make it too loose the hatch wont seal properly. If you make it tight, you can pick the boat up by the hatch and it wont move at all. If I was doing it again I would make the toggle overhang a little less.

Launch of the New kayak

Took the complete new kayak out for a quick spin in Lake Okanagan. I am pretty happy with the performance, nice and stable, tons of room inside. I notice it takes more effort to paddle than my 14' boat, probably just because of the increased hull friction, or I messed up the shape. Its not too bad though. I need to redo the hatches some, with the current system I am using a closed cell foam gasket and it takes too much force to cinch it tight.
The decklines are made of latigo, with walnut sliders, and mystery hardwood balls to keep the lines off the deck so I can grab them easier.

Completed Frame and Saran Test

Got the frame of my new Aleut Baidarka done, and I am pretty happy with it. Took it out for its maiden voyage on an seasonably chilly April day, though just with a cling wrap skin.

Dimensions are 16.5' long, 21" beam, 14.5" deep from bottom of keel stringer to top of cockpit at masik. Materials are:

• Lumberyard spruce for the gunwales, deck and keel stringers (I scored an awesome beat up 2x10x14' that was nasty in the middle but perfect on the edges)
  
• Willow and dogwood ribs
• Sitka spruce bow and stern assemblies
• Pine hull stringers (Thanks Don!)
• Red cedar floorboards
  
• Glue-lam deck beams, coaming, and hatches. (made of fir, spruce and pine. Stuck together with PL Premium
  

The deck beams are all mortise and tenon, I found it gives more lateral flex in the gunwales. The hatches are added in by cutting the deck stringer, putting in two bridge stringers to take the force and support the hatch, and adding a round coaming and a plug hatch.
Oh and the gap in the floorboards is so I can drop a bilge pump beside the keel stringer.