Hi all, my old boat has an aft deck with raised hatches ( left over from her days as a fishing boat ) in the interest of crew safety I want to get rid of those trip hazards and make a flush hatch of a usable size. Am I on the right track with this plan ?
Toe kicking trip hazards
I can see the toe-stubbing problem with your old hatches.
Your proposed design has the big advantage of simplicity, but, because of the geometry, if a wave washes over the deck and fills that 40mm channel with water, the seal between the underside of the hatch and the lip (gasket) will have to be perfect all round to stop water from leaking down below.
Just build the deck height up to top of hatch
or my 2 cent drawing
Flush finish, no gaps for water or crap to build up, drain is only a secondary precaution
Keep the hatches as they are and educate your crew. Or raise the height of the fixed part and install pins so that they don't wash overboard.
i have this setup for my engine hatches on my Fusion 40. They leak and as far as I know this is a problem on most Fusion 40s. However I think I am close to a solution. ONe of the answers is to put the gasket on the lip rather than the lid as you have shown. This will raise tthe water level to the height of the deck and it shouldn't go inside. If you could raise the level of the lip to be slightly above deck level as depicted by Craig66 then I reckon you will be close to a solution.
Another way to do it is to put wedges of timber around the hatch, parallel to the sides of the hatch. That way those fumble feet will only hit a sloping surface rather than a right angle.
Personally one of my hatches is pretty tall and square sided with a very high lip, and I really like never having to worry about even green water finding its way down below onto the Vee berth. However, because it's varnished it's very easy to see even subconsciously, and having owned the boat for 30+ years I can remember the layout.
The original front hatch of the Joubert Currawong 30's (and Brolga's I think) were designed similar these proposals. Almost all have been replaced. Some have been replaced with the type you currently have.
There are two problems with the proposed design :
The first is that in heavy seas the water in the drains will back wash or over flow up through the gasket when the boat rolls. The drains will only work when the boat is level.
The second is that capillary action will suck the water through the top gasket gap and drip over the lip.
For it to work the tolerances need to be extremely tight to ensure that no more water gets in than is drained. The drain needs to be very big and gaskets need to seal very tightly.
I have completely rebuilt mine and almost got it right, but it still takes on a little water when beating into a hard chop. I am sure they worked when they left the factory in the 70's, but not for long.
Here is a photo of my front hatch with one of the gaskets that I was experimenting with.
I don't recommend this design, keeping the water out should be a higher priority than removing a trip hazard.
A
Thanks for the inputs, I have to admit the existing hatches don't leak at all, even on the odd occasion when a wave is shipped 
I think the idea of raising the deck around the hatches would be the easiest, you could knock up a nice teak grate, or timber deck-type looking area around the hatches.
Are the present hatches locked down from the inside?
I mean , can you access those compartments and are the hatches really needed? I would guess that they are.
Why are there three hatches?
Can you eliminate two of them and trim around the remaining one?
Select to expand quotegarymalmgren said..
Are the present hatches locked down from the inside?
I mean , can you access those compartments and are the hatches really needed? I would guess that they are.
Why are there three hatches?
Can you eliminate two of them and trim around the remaining one?
Below that deck is a good size area that can be accessed thru the bulkhead, crew or over night visitors usually claim as it has a double berth.
The two aft hatches are unnecessary, the centre one under the tiller is good for ventilation and access for slim folks.
the idea is to make a larger hatch on the port side as the trip thru the bulkhead is a bit of a scramble Select to expand quoteBlueMoon said..
I think the idea of raising the deck around the hatches would be the easiest, you could knock up a nice teak grate, or timber deck-type looking area around the hatches.
Yeah good idea, it would buy pass the need to replace matting as well, and wouldn't look out of place ??
Why fix it if it ain't broken?
You are creating yourself a future problem instead of buying a six pack and a box of bandaids for the dummy who kicks it.
Ok so no one has a good experience with flush hatches, so that's out. Raising the deck would be good except I've a hard Bimini over that deck and would be hitting my head instead of toe kicking ! And I can't lift the Bimini without raising the mizzenmast, so that's out. Conclusion, get rid of the blood stained &@!$!? fwd centre hatch and see what life is like then. Thanks all for your insights and suggestions 
