I have never tried to do a seamless seal, so for what it is worth. I usually use 3/8x3/4 weatherstriping from the big box store, cutting the end about 1/4 inch longer and squishing them together. I build flush hatches, and I usually delete the little rim, only have it on the first 2 kayak I built. Except for my CH17LT, which has a warped hatch lid, they don't leak. I haven't seen a difference either way. Smooth surface, the right tension seem to be key. Nice looking kayak. good luck. jrc.

   JRC,

Thanks, this is going to be a March project I am just thinking ahead. https://www.mcmaster.com/# has a wide variety of adhesive backed foam sheets so I should be able to find something that will work. call them for information and I will experiment a bit before I actually attach anything to the hatch covers. If I find something I reallly like I will post it here.

Mike

i have built several of the chesapeakes with the weatherstripping....and no problems being waterproof.

so if you are looking to do it from a continuous sheet to acheive 'waterproofness'....it is simply not necessary.

as JRC described it, would be my approach with the following exception...the little hatch lip does, in my view make it easier to get the waterproof seal.  so i would install that little hatch lip.

as JRC mentioned, the key thing is the right tension and that the basic shape/curvature of the hatch/hull ensures that the gasket is fully engaged around the entire hatch.   the advantage of the hatch lip is that is very easy to confirm that is the case becuase if you see that the foam has no gap between the hatch and the hull looking from the outside....the lip ensures that there is more than enough compression of the foam on the inner ring over the lip.  you can also clearly see the inprint of the lip on the foam when you remove the hatch.  if you don't see it....its not tight enough. (without the lip....there would be no visual sign confirming compressed vs a not compressed gasket)

fwiw...i have also never had a problem with a hatch coming loose in rough water.   to compress the foam to wateproof tension..it will be tight....its not going anywhere.

h

H,

Thanks for taking the time to respond. After reading you responses I will probably just go with the included weatherstripping. The hatch lips are already glued in place. I have placed the hatch covers over the holes and they both fit well so I should not have problems. I do not anticipate any ocean paddling in this kayak but it will see large lakes.

Mike

I'm the one with hatch shifting in rough water. The problem with that particular hatch, on my boat, is that;

 1. The radius of the hatch is not the same as the deck radius. Thus some hatch parts fit tighter than others.  Even with that water intrusion is minor in normal 1 to 2 ft waves inshore, rivers and lakes.

2. The strap tension was not sufficent to prevent movement of the hatch even though the weather stripping and rim were engaged. The kit design has two "ribs" that determine radius of the hatch. They are installed laterally (side to side). The addition of a pair of stops along the fore-aft center line stopped this problem.  Note it was only a problem when attempting surf entry plowing through 3' +/- surf. The surf disloged the hatch 1" aft allowing ALOT of water to enter the forward compartment. Which at the time was a secondary problem after the third wave compaired to rolling sideways in the surf up the beach.  Water exits with the skirt are relatively easy.. Collecting deck stowed gear strewn down the beach is more difficult.  Of course strap tension was not checked prior to launch.

..

I built my hatches in a hurry to get done by a deadline. Taking time to make them fit right will likely prevent these problems.

.

Paddling on lakes and rivers is no guarentee that there won't be large waves. Lake Marion in SC, The St Johns river have sections with a fetch over 7 miles.  A 20 mph wind can be impressive.  A 30ft + motor cruiser makes a large bow/stern wake(s) at speed. I've seen them coming down the ICW with waves covering the marsh grass. However, none of these have been a problem as long as they were not breaking waves.  Kinda fun actually.

Thanks Grumpy, I am guessing that the forward hatch would be the one that would be more likely to dislodge, I have a pretty tight fit with the hatch frames on the forward hatch and the radius is better on the forward hatch. The rear radius is not perfect but very close and the rear hatch frames allow for more movement.    If I find I have a problem I will adopt your centerline stop solution, I appreciate the tip. I have an 8-12 day trip planned on Lake Yellowstone next year, I will probably see some waves. I plan four days of day paddling in Grand Teton prior to the camping trip to work out any bugs. I built this to be a working boat and I want to give it a good workout.

Mike

Our experience with  Yellowstone Lake is the wind starts at noon.   

   Grumpy

Thanks again, I asume we will start early but it is not my trip. I am along for the ride but I am looking forward to it. The organizers own his and hers 17 year old Chesapeakes, both beautiful boats. They are staunch believers in rudders (especially for quartering tail winds) but I am not convinced I want to go that way. When this boat is finished I will own one canoe and four kayaks and almost all of my paddling has been rudderless. I have never been as excited about a boat as I am about this kayak. My first kayak was a home built, canvas over a wood frame, I was 17 and snapped the keel beam riding the surf in the Atlantic off the coast of New Hampshire. A breaking wave drove the bow straight into the sandy bottom.  I removed the canvas, repaired the damage, put on new canvas and passed it on to my brother when I went to college. I have always loved kayaks.

Mike

On my Chesapeake I replaced the gasket that came in the kit with automotive type self-adhesive hollow rubber weatherstrip that I got from Advance Autoparts.  I laid the weatherstrip around the  edge of hatch cover then, cut it to the length I needed then peeled the backing off and stuck it to the hatch cover.  Then I cemented the ends of the hollow weatherstrip together with black weatherstrip adhesive (also from Advance Autoparts).  It seals much better than the foam weatherstrip that came with the kit. 

I got the idea from my 15 year old Impex Susquehanna kayak that has fiberglass hatch covers with an automotive type weatherstrip. 

   Thanks, I like this idea and will look into it.

Mike