Trimaran sailors..........

[w32honu]

Greetings All,

In the process of building some hatches for the Amas. The size of the opening requires custom built hatch covers. I could not go with anything off of the shelf.

For water tight integrity the hatches will have double combings. There will be a latch to dog them down. And they are located just aft of the forward Aka fairing so any green water rushing by will be deflected.

Our hope is for a water tight and trouble free hatch.......

I am curious if the Forum has any input?

What has been your solution or solutions?

Do you set up a routine during passage to check for water in the Ama bilges?

Any personal experiences worth sharing? Anyone had any bad experiences with flooding? Obviously a bad deal when we are dependent on the buoyancy of the Ama.

And what about methods of pumping out in the event? Electric bilge pumps? Manual? What about the pick up? I would like to avoid opening a big hatch while at sea in rough conditions.

Any good sea stories to share along these lines?

Thanks in advance

[Cavalier MK2]

Use seals. Neoprene, fridge seals in a pinch but don't count on just the coaming. Whatever you do for latches make sure they can apply pressure for a seal.

A bilge alarm can let you know if there is water, mine stay dry but I've thought a camera system might be neat. One thing that is a good idea is a smaller access deckplate for bilge pump access if you don't have any installed. This is so you don't have to open the big hatch.

[honey badger]

have a look on "Wharram Builders and friends " mate.

[w32honu]

Thanks guys.

No big sea stories to tell is a good thing I suppose.....

May everyones Amas stay dry and buoyant.

Cheers

[Cavalier MK2]

Well the outer coaming is the first line of defense but the seals are the guys in the trench so to speak.

[w32honu]

Thanks Cav,

I think the double combing will do the trick. But good advice you have..... plan to have a seal as well. Thinking maybe the spongy soft ones like on an oven door. Or maybe off the shelf adhesive stuff.... The usual for cockpit lockers and the like.

[Roy M]

Coamings all around the hatch slow water down, reducing the pressure of water trying to infiltrate into the amas. Good, lively rubber gaskets increase the resistance to entry. Using piano hinge on the outboard side of the hatch ON TOP OF THE ASSOCIATED COAMING, coupled with latches that require you to stand on the hatch to secure, thus preloading the water tight seal, make for a solid hatch. But then, because Murphy's Law has not been repealed yet, having bilge pumps makes excellent sense. Having both automatic electric pumps and manual backups isn't a bad idea. What could possibly go wrong?

[Cavalier MK2]

Yes I have the piano hinges as well. My outer coamings are on the front and inboard side as with the Nicol's cambered deck heeling while driving through waves that is the direction the water comes from. The advantage here is any water going over the coaming isn't trapped and allowed to pool but continues on out the back and over the side. Not my planning but Hedley Nicol's.

[Roy M]

Good point Cav, I neglected to include that there needs to be a drain gap between adjoining coamings to all draining, and the otherwise increased pressure of water trying to enter the amas.

[w32honu]

All good info .........thanks. These hatches will have double combings under the hatch. It should be hard work for any water to get in. It will have to compress under the hatch. Then over the first combing and down. Then over a second combing.

Seals we talked about.

Might add a breakwater as a deflector. That would be on the leading edge of the hatch and the outboard edge. Not sure that it will be needed tho. The hatch is just aft of the forward aka fairing. And that should be a good deflector of any green water.

Still a work in progress.

[Roy M]

Send pictures when you get there.

[Cavalier MK2]

I'd put them on the front and inboard side. Remember in any wind your windward ama will fly so on the lee ama a outboard deflector is just going to keep the water in the neighborhood longer.You want to deflect the stuff running along the deck.

[Cavalier MK2]

Had to think about the CCs for a minute, yes that front aka will run a lot of interference.

[paxfish]

Only the hairiest of hatches need "combing"....

Here's a pic of a hatch in the olden days:

[Cavalier MK2]

I won't argue with its leakproof construction but will point out it is tall enough to have windage as well as strong wave impacts if water is going across the decks. A cruising tri can hit speeds old Maurice wouldn't have believed.