Silicon Gasket

[tx river rat]

I decided to try laying a gasket and see how it works.
I sanded the lips just to rough them up

Then took a tube of silicon and laid down a heavy bead

Then I covered it with saran wrap

then eased the hatch cover into place and put presure on it till it was the right level

They turned out pretty good for the first try

On the next one I will wrap the plastic on the hatch cover,should make it a lot easier.
I need to trim these up but am going to let them sit overnight.
Ron

 

[Kayak Jack]

Ronnie, it looks like the plastic wrap had wrinkles in it, and they each created a channel. Some of the channels go full width across the silicone implant. I suggest very carefully stretching the wrap next time, and applying a thin of silicone silastic over the original one. That should provide an even seal all around.

 

[Wannabe]

Jack,
Wouldn't those itty bitty channels in the silacone give the hatch the ability to breathe and not create a vacuum or a pressure build up?
I have no experience in this. Just curious.
Bob

 

[tx river rat]

:shock:

This was a little experiment ,and after I tried one Darrel reminded me of something I didnt do.I should have laid a heavy bead of caulk and the let it sit for 15 or 20 minutes and it would skim over then put the hatch cover on and tape it for 24 hours .
I will try that next time.
I think the hatch cover will compress it enough to take care of the wrinkles ,but on the next one the plastic will be on the hatch cover instead of the boat.
Ron

 

[Kayak Jack]

Ronnie doesn't believe in effects of pressure differences, Bob. So for his boat,they don't exist. :wink:

If it were my boat, there'd be a pinhole in the bulkhead up hear the top for air to breathe in and out while the hatch was sealed. In storage, leave the hatch lid off so the area can dry out. But, it isn't my boat. It's a lovely boat and will serve Ronnie well.

 

[tx river rat]

Oh I believe in them I just don't believe anyone on her can build a conventional hatch that will hold pressure.
Bunjis just want hold tight enough to hold presure.
:lol:
Ron

 

[Kayak Jack]

Ron, here's a thought for holding your hatch covers. Bungees hold compression, but an elastic outer limit. Straps hold a definite outer limit, but not compression. Using both bungees and straps will give both kinds of security. Then, some folks wedge something under straps after they're buckled, to give even more pressure against the hatch cover. Just a thought.

Some builders have run two beads of silastic around a hatch. One bead on the cover, and another on the lips of the hatch opening. One bead circumference would be outside the other.

 

[tx river rat]

Jack
Some good ideals..
Let me explain something that Jack and I agree on but disagree on.
His theory is dead on but like a lot of theories , you start putting other variables into it the pure theory goes out the window.
Hatch cover are one of those things, with bunji cords and straps and blocks you will never put enough pressure on to damage a hull. Another theory comes into play hydroldics ,with the size of my hatches ,if you could build 1 lb of pressure there would be over 250 lbs of pressure pushing up on the hatches There is no way a simple gasket are the holding systems we use will hold that ,one small section leaking will loose the pressure in a heartbeat. So to me it is a non issue.
Jack like open spaces under deck,I dont,Drives me crazy to have to drag everything out to get to something I need,dont like standing on my head looking, with hatches I dont have to do that. Now Jack is going to tell me if I was organized I would know where everything was( I have paddled with Jack he aint that organized :lol: :lol: ) You basically have a few choices on flotation and non are perfect, closed decks like I use,floatation bags,they can leak to ,foam works but like the floatation bags takes up room that that I dont loose in under deck storage. Open boats like canoes,better have it tied down, is out in the elements and if it rain just as with Jacks open under the deck configuration everything you have that isnt sealed is wet.
Jack and I kid and pick on each other a lot and dont always agree,thats good it gives a different perspective and let folks use there own judgment to build the best boat for there location and usage.
My boats are built for high winds ,shallow swift water ,deep holes. PADDLING ON THE BRAZOS and I will keep trying to improve them for my usage. Besides I like to pick on Jack :lol: :lol:
Ron

 

[Kayak Jack]

Ronnie and I disagree on a lot of stuff; that's why we get along so well together.

Now, Ron, think of 0.005 psi pressure differential instead of a pound. That makes only 1.25 pounds of force on your hatch cover. Deal with that.

And he's right, I'm not that organized. But - I am better looking. So there! Nanny nanny nanny! :wink:

 

[tx river rat]

0.005 will still find a way out and if my hull is so weak it could stand that I am paddling a noodle.Like I said it is a non issue
If you dont believe that figure the outside force on you hull when you and your gear are in it. Way more than than 0.005.
Gotcah
Ron
oh and it is a whole lot easier to build something that structurally will hold internal pressure than external pressure.

 

[oldsparkey]

The silicone looks like a good deal but on mine I used the foam tape ( sticky on one side) put it on the lip the hatch fits on and after fitting the hatch cover on there it form fitted to the tape making a good seal that does not leak. Well it did let some water in there but only when I removed the cover to get my stuff out while it rained on me. :wink:

Like Ron , I prefer the sealed compartments with the hatches , makes getting to everything a lot simpler and no matter how you pack a kayak what ever you want is always in the farthest part of the boat.
That is one reason I prefer a canoe , wide open and everything is right there for you , take out what you need and leave the rest in the boat. Waterproof bags do a nice job of keeping everything dry and organized when paddling.

I do not strap them in the canoe , if I spill ( like I did on the Buffalo River ) I want all of that out of the boat , an empty boat is easier to handle and what ever is in the river is floating so it can be picked up later. Look at it this way , all of the gear has it's own Personal Flotation Device. The only thing lost when I took that involuntary swim was one sock , found the other one. They were on top of one of the bags trying to dry out.

Might say doing it that way also works as a warning to the other paddlers ( when paddling with a group) that some one took a spill... They noticed my stuff floating down stream before they knew I went for a dip. The guys gathered the stuff as it floated along.
Same thing in the Okefenokee when the Gator flipped the canoe Bill and I were in... The fishermen coming along noticed the stuff in the water and knew something was wrong.

Chuck.

 

[tx river rat]

Chuck
I have been using the same seal on my yaks ,but I have a couple problems, I have large hatches and over time it shrunk leving a gap at the ends, the other thing was the adhision after a few months tended to come loos. These are the reason I am trying something different.
Ron

 

[Kayak Jack]

0.005 will still find a way out and if my hull is so weak it could stand that I am paddling a noodle.Like I said it is a non issue
If you dont believe that figure the outside force on you hull when you and your gear are in it. Way more than than 0.005.
Gotcah
Ron
oh and it is a whole lot easier to build something that structurally will hold internal pressure than external pressure.

You are partly tight, and partly wrong. A boat hull is deigned to withstand external pressure. As something external presses in on a point or area of a hull, the hull is self bracing. Not so with internal pressure.

You're right that any pressure differential will leak past your gasket.

 

[tx river rat]

Boat hulls are not designed for external presure ,they are designed for function and usability and displacement of the hull shape . Fill your boat up with water sitting on blocks ,it will hold it without a problem. figure the lbs per sq inch on that.
Again theory compared to fact ,like I said It is a non issue with me.
Ron

But dang its fun to argue with Jack.
:lol:

 

[Kayak Jack]

Ron quit trying to cloud the issue with stuff that doesn't apply. Smoke screens don't hide your error. Stay on track here.

If boats don't withstand external pressure, they would collapse - not theory, just fact. Set your boat in the water, you set in the boat, add a few gallons of water, drill a hole in it below the waterline, and see which way the water flows. HINT: it will flow from high pressure to low pressure, every time.

Our wooden boats are basically a full monocoque construction, the strength comes from the skin rather than an internal frame like a house. We do add bracing around hatches, cockpits, etc. as necessary if we interrupt the contiguous shell of the hull. Technically, this converts the hull to a semi-monocoque. Again, not theory, just fact.

 

[tx river rat]

Jack
If you fill the hull I bet the water will run the other way.
Let me explain what I am saying, internal pressure is easier to contain with less strength.
Simple test take a milk jug fill it with water no problem. take that same jug empty it and submerge it in water
the jug will collapse. same amount of structure just different pressures. I use to build a lot of diesel storage tanks ,even a
500 gallon held several thousand lbs of fuel but if you forgot to open the vent just ounces of vacuum would fold it up like a paper cup.
My point is a sealed compartment with our hatch system will never fracture the hull, pressure will be released long before that ,and your boat will take more pressure from inside than it will externally.
Ron

 

[oldsparkey]

Easy way to make sure your kayak is not damaged by any sort of pressure...... Don't send it anywhere by airplane , especially the really high flying ones. "O" ...Also the deep submersibles.

The pressure difference is something ...... For every 1,000 feet you ascend the atmospheric pressure ( 14.7 pounds) decreases by 4%. So on a sealed unit at sea level the pressure inside the unit should increase by 4 % since that 4% pushing on the outside of it is gone. So you would have to gain elevation just less then 4,000 feet ( 3,675) to have one atmosphere of pressure pushing against the hatch. Providing you started at sea level.
While every 33 1/3 feet you descend into water the pressure increases ( 100%) one complete atmosphere or 14.7 pounds on the outside of the object. Might be why we tend to keep our boats on the top of the water.

Using diving ( since I am familiar with that ) the atmosphere of the air in a container looses 1/2 of its volume ... A bottle ( no cap on it , neck down) at sea level , full of air ....33 feet 1/2 full , 66 feet 1/4 full and so on .......... It would be the reverse for the same bottle increasing in altitude but it will take that 3,675 feet for each step to double and accomplish the same thing.

In conclusion.... If you had a kayak with a well sealed hatch and went from sea level to the top of the Rockies to do some paddling there is a good shot the hatch would leak and let some of the pressure out , if not it would be really easy to open that hatch.
In reverse if you were out there and sealed it and came back to sea level it could be a stinker to open. Especially since the pressure would be pushing down on the hatch trying to get in .....not out. Good shot it would not be a problem since the descent would be gradual and over a couple of days and it is bound to leak some degree since it is not as air tight as a vacuum ( home canning ) jar. Anyway my boats are not that tight , there is always one little spot that is missed ... somewhere, by mistake.

Chuck.

 

[tx river rat]

Meanwhile back at the ranch I said Gabby believe I am going to like this new seal. :lol:
Ron

 

[oldsparkey]

Meanwhile back at the ranch I said Gabby believe I am going to like this new seal. :lol:
Ron

Darn .. Ron .. Give Gabby ( Jack ) a break he is older then the stones the glaciers moved down here millions of years ago and has more excuses for it then anyone ..... He needs his rest and lots of it , might be why he naps at Pipers and misses a lot of the action.

Be kind to the prehistoric ones on here with there delusions of grandeur..... Everyone needs a straw to grasp and hang on to..... You young whipper snappers will not know about that till you get there............ :roll: Then you will wake up , energy is wasted on the youth , knowledge is wasted by the elderly since the youth will not listen to the almost old farts. We have been there and done it .

Yep....... I came to Jacks rescue on this one since I am a lot younger but wiser about some things here in the south ...... Never been her for a lot of years the do not tell us how to do it , we have manged for decades.

No one can suggest anything about the south till they have walked in the shoes of a southern paddler or paddled there boat till they have been down here for long time...........As in living here for most of there life.......... We have a whole different wold down here in camping and paddling.

 

[tx river rat]

I started to tell Jack to go fly a kite opps plane :lol: :lol: :lol:
How you like the solo flying?
Ron