New deck hatches, how large?

[GILow]

Hello Cruisers,

I am about to start fabricating a new set of deck hatches. For various reasons I have decided to make my own, but with this has come a pleasant dilemma.

How BIG to make the opening.

The current two foredeck hatches are the classic 600mm x 600mm, the rear hatch is a lot smaller.

The spacing of the deck beams is such that I can probably go out to close to 800mm between beams, and of course width is very much "anything goes". A 12 foot wide hatch? Not out of the question, but probably a bit silly.

So, I can currently squeeze through the foredeck hatches pretty easily, and if they were a little smaller I could probably still do so. The rear hatch, not so good, given a bit of serious desperation I could get through it, but it is not a safe exit really. It needs to be safe, there is no other way out of the rear cabin if there was an engine or galley fire.

The Swanson 42 has really big clear open decks (see photo), there is absolutely nothing even remotely near the foredeck hatches, and the rear hatch also has plenty of space around it.

So in this situation, how large would you make the hatches? Is there any benefit for going larger than the current 600mm setup? Any benefit for going rectangular vs square? Any gotchas on size that I might not have considered?

Matt

[Snowpetrel]

Extra length might be nice, I'd go Ionger fore and aft not athwartships. Things like rolled up dinghys, anchors, sails and getting old tanks in and out can make a bigger hatch handy.

I'd consider a raised coaming around the hatch, maybe 150 mm high, or even more. Much dryer, and less chance of falling down an open hatch.

I have made some to a very successfull design, using stainless channel for the surround. With aluminium hatches, happy to draw it up for you, but it will have to wait till tonight. Cheers

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[GILow]

Hey Ben, if you show me yours I'll show you mine! :^)


Seriously though, I'd love to see what you came up with.


I am planning a stainless steel coaming using angle (was only thinking 50mm but I would appreciate arguments for going higher).


I was also planning on stainless steel for the hatch frame as well but I was going to do the coamings first and get a feel for the weight before deciding on stainless vs aluminium for the hatch. If I went Aluminium for the hatches I will be less confident in my welding. So far my ally welding has had the strength and appearance of so much bird poop.


Matt

[GILow]

FWIW, with our somewhat significant freeboard and fat bow I am yet to see ANY water get on the deck from a wave. And I have pounded through some ugly stuff to test the theory. Mostly the boat throws water outwards and down, very little spray gets blown onto the deck.


So I am, maybe naively, thinking of the smaller coaming to get the hatches down as flush with the deck as practical to avoid snagging sheets etc and assuming that if things are wet enough for water to be coming over the deck I will have them firmly battened down already.


But, we've not yet been in anything testing.


Matt

[Jim Cate]

Good questions, Matt,

For size, I would want them big enough that I could get out through them wearing full wet weather gear, and that looks like perhaps 750 rather than 600 mm more or less. not much downside for making them a bit bigger IMO.

The coamings should have sloped outer edges... that way nothing will snag on them. Ours are just shaped timber, 50 mm high which is the same as the height of the hatch itself. Thus any water stream is deflected over the hatch body completely; it is amazing how much this helps a hatch seal remain water tight. We seldom bother to dog down our hatches, and have never had any water get through them (touching wood surreptitiously).

Cheers,

Jim

[Steadman Uhlich]

I like the idea of the raised coaming on the foredeck hatches.

What follows is some musing and may not fit your particular boat or desires, but they are things I would consider if looking at that big open foredeck and considering changes to the layout to suit my preferences.

1. I would consider a second, inner stay.

2. I like Dorades and would put two Dorades (one on each side of the hatch) with some guard going over them. Because Dorades have a box beneath the cowl vent, this means the raised coaming for the square hatch would not stick up higher than the Dorade boxes, and the stainless pipe guards over the Dorades will keep the lines from fouling on the coaming. I would make the guards sturdy and secure to the deck, so they double as handholds when working on the foredeck.

3. As I would not be using the boat for racing, I would probably cut my jibs higher anyway (better visibility).

4. I would also add some hard points for attaching jacklines in the center, and a good place to clip on when the boat is heeled or as attachment points if you carry gear on the foredeck while voyaging (e.g. some type of dinghy).

[GILow]

Originally Posted by Jim Cate

Good questions, Matt,

For size, I would want them big enough that I could get out through them wearing full wet weather gear, and that looks like perhaps 750 rather than 600 mm more or less. not much downside for making them a bit bigger IMO.

The coamings should have sloped outer edges... that way nothing will snag on them. Ours are just shaped timber, 50 mm high which is the same as the height of the hatch itself. Thus any water stream is deflected over the hatch body completely; it is amazing how much this helps a hatch seal remain water tight. We seldom bother to dog down our hatches, and have never had any water get through them (touching wood surreptitiously).

Cheers,

Jim

I was hoping to avoid embarrassment by seeing Ben's drawings first, but here is roughly what I was thinking of, hopefully similar to what you are suggesting. A bit rushed and does not show all the important stuff like drain holes to let trapped water out from between the timber surround and the inner coaming angle.

Thanks also for the thoughts on size, I do like the idea of bigger, but aside from Ben's valid point about not disappearing into one when it is open I am not yet hearing any negatives for the idea. This is reassuring because, sadlly, I am not getting any skinnier.

[Snowpetrel]

Mine where flush, or rather low profile, with sloping edges to the hatch. 100% watertight. I guess my thinking about the raised coamings is not so much watertightness, though it might help, but more about the danger of falling down such a big hatch on a flat deck. Having done it once, it comes as quite a surprise when your foot suddenly disappears!

Another benefit of the raised hatch is it makes a nice seat, and a good feature to brace against in rough weather. But it all depends on your layout, and what you have that might snag a hatch. Another consideration is dinghy stowage.

It's nice if you can stow the dinghy right way up on the foredeck for short hops when inverting it is a nuisance. This often requires a flush hatch that it can sit over. Ideally the upside down dink also sits over the hatch for long passages, such that the hatch can still be opened for ventilation in most weather (in this case the raised coamings really help) and also for emergency escape in a pinch (might need a knife to cut the sink lashings...) Anyway I'm sure whatever you do it will be well thought out.

What's wrong with the old ones?

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[GILow]

Originally Posted by Steady Hand

I like the idea of the raised coaming on the foredeck hatches.

What follows is some musing and may not fit your particular boat or desires, but they are things I would consider if looking at that big open foredeck and considering changes to the layout to suit my preferences.

1. I would consider a second, inner stay.

2. I like Dorades and would put two Dorades (one on each side of the hatch) with some guard going over them. Because Dorades have a box beneath the cowl vent, this means the raised coaming for the square hatch would not stick up higher than the Dorade boxes, and the stainless pipe guards over the Dorades will keep the lines from fouling on the coaming. I would make the guards sturdy and secure to the deck, so they double as handholds when working on the foredeck.

3. As I would not be using the boat for racing, I would probably cut my jibs higher anyway (better visibility).

4. I would also add some hard points for attaching jacklines in the center, and a good place to clip on when the boat is heeled or as attachment points if you carry gear on the foredeck while voyaging (e.g. some type of dinghy).

Sounds like you would be a handy guy to have aboard.

In order of your points.

1. Inner stay... do you mean staysail stay? If so, it's there. What, you can't see it? Look harder. It's tucked over on the starboard side, with a bloody great monster of a highfield lever on it. you can just make it out behind the aft of the two foredeck hatches, it is pulled forward by a white pulley and then heads up the mast, near the staysail boom. You can also see the smaller highfield for the starboard running back stay immediately aft of it, beside the intermediate stay.

2. Dorades: Hmmm... interesting. These are on the maybe list at the moment. There is a more common layout of the Swanson 42 that has two nice big dorade boxes running forward from the deckhouse. I am of two minds. Some I have spoken to who have them hate them with a passion, they trap water and block access at the mast, others love them. I am waiting to see if there is enough pressure/need from other systems to justify them, clearly your point here is in favour of adding them. I am also looking to safely vent a diesel heater, they would provide space/protection for such a flue.

3. Done. Most certainly not racing, and we have a high cut yankee and a high cut reacher that you look straight under when under way. The staysail is not so vision friendly, but when using it I figure you are on a long haul anyway and are not in crowded waterways. I might find I am wrong with that assumption, but so far so good.

4. Jackline points, done also. Got very good strong mounting pints and I have a pair of the nice strap sort that lie flush on the deck, and run from beside the cockpit all the way to the bow. No need to unclip as I go forward. Not so well covered for the after deck, but there's a fair bit more protection back there, and you can do most stuff without releasing the safety harness from the clip in the cockpit.

[GILow]

Originally Posted by Snowpetrel

What's wrong with the old ones?

Ben, re all the staff before this, good points thank you. Will take into serious consideration.

As to the old ones... totally and completely buggered. Some kind of synthetic frame, halfway between nylon and fibreglass, has started to crumble with age and feel like they will soon just snap. The lexan/Perspex/see-thru-stuff is crazed like a safety glass windscreen after a headon prang. The rubber gaskets are brittle and perished.

There is only a token change in the amount of water that gets through when they are open vs closed, at least when they are open the water is nicely distributed rather than focussed into a couple of small rivers.

[Steadman Uhlich]

These two photos from my files show you what I have in mind. Of course they could be adapted a bit, with the guard possibly being joined in the middle by an athwartship SS tubing. I would pick large Dorade cowls. The hatch can go between the two Dorades. I see this for your aft hatch (still before the mast).

Why do I like Dorades?
I was on a boat in a true gale (the edge of a passing named tropical storm), and having experienced the real discomfort of hours underway, while heeled in a hot, humid, stinking, boat that is "buttoned up" and tossing about, I believe good Dorades are a MUST for my future boat and will have several and make sure they work (shed water) and are big enough to vent properly and guarded (with SS pipe) etc. Good ventilation is nice. Good ones may cost, but I believe they are worth it and will gladly pay for them or make them.

[Panope]

GILow, I will second Ben's suggestion of a raised coaming/hatch. I took the idea to the extreme and made a hatch that doubles as a bona fide seat. The seat back tube has proven to be an effective "granny bar" when working at the mast. I have not yet had a line snag on this hatch/seat.

Steve

[Snowpetrel]

^^glad you piped in Steve. I very much had your clever solution in mind, and was going to try to link to your thread. Another plus is being able to store a coil of anchor warp around it, and put some deck locker space into it. Also a couple of small windows could be added.

I completely agree with steady on the need for dorades. Been caught in a blow with none. The inside of the boat ended up like a sauna after a day or so. Might not be as bad on a bigger boat, but not something I'd want to experience again.

But all this talk of raised hatch, it would be more work and it may not suit your plans for the foredeck layout.

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[GILow]

Well, plans are made to be changed, and I'd be a bit of an idiot if I did not consider all of these ideas just because I hadn't thought of them myself. Thanks Steady and Panope for broadening the scope.


I'll grab some cardboard before I go down to the boat next and mock up some of this stuff, then report back.


It's all very thought provoking, thanks guys.


Matt


P.S. Ben, I have shown you mine, but I'd still like you to show me yours.

[GILow]

Originally Posted by Panope

GILow, I will second Ben's suggestion of a raised coaming/hatch. I took the idea to the extreme and made a hatch that doubles as a bona fide seat. The seat back tube has proven to be an effective "granny bar" when working at the mast. I have not yet had a line snag on this hatch/seat.

Steve

Steve, further to this a little... do you have any hand holds or a ladder of sorts to get out through that hatch? In our boat we can stand on the settee and heave ourselves through the hatch as it is currently configured, but that extra height would make that impossible. Maybe steps on the forward bulkhead door would help in our case.... but is this something you had to manage?

Matt