HATCH CONSTRUCTION

[sgunns]

I am having a classic 1924 Nicholson ketch restored. I wish to have an external hatch built without hatch garage, (as appears to be the norm on classics), but the boatyard has advised that they cannot build a leak-proof hatch of this style. Has anyone any comments, or best, can a good method of construction be advised.

Steve Gunns
Sydney

[Wooden Boat Fittings]

.
Steve, Maurice Griffiths had a design for a leakproof hatch of the "hinged forehatch" variety -- highly recommended. (He said it had to be under water before it would leak.) It has a type of built-in scupper arrangement, on a somewhat similar principle to a Dorade ventilator box.

But I suspect you're after a typical sliding companionway hatch, are you? If so, this mightn't sbe particularly relevant.

If you're interested though, I can scrounge up a drawing to post.

Mike
.

[sgunns]

Mike,
Thanks for your comments. You are correct in that I was looking for a companionway hatch, so probably your sketch won't help. I know of the principle for the hatch you speak of, but it does not look terrific.
Steve

[ssor]

Steve, When I rebuilt "Bietzpadlin" I too wanted a sliding companion hatch. I built a 4" high combing on three sides of the companion and then constructed a coopered hatch with vertical sides and fore-end. It is carried on slides on the combings. The aft end has a hinged flap that covers the tops of the doors when everything is closed. The arrangement doesn't leak unless I take green water over the deck and splash it against the forward end of the hatch. I left substantial gaps between the boards and caulked with urethane caulk. BTW when the caulk allows for fifty percent joint movement, a quarter inch joint won't tear with less than 1/8" movement. A nice tight 1/16" joint will tear the caulk if it moves only 1/32". Please don't ask how I know that. redface.gif

[uncas]

ssor...sounds a good deal like my hatch...The slide mehansim might be a bit different...I have 4, 2.5" square bronze plates which fit into the grove on the side mounts and are attached to the hatch...
For one thing...having only 4 attachments, the hatch is easy to remove...
I don't have a hinge but a slight overhang...perhaps 1.5" over the entrance...
If nothing else, it doesn't leak
Another thing I like..although it can be a pain to unlock in the dark, is my hatch is locked on the foreward end...Hard to get to if someone is trying to break in by cutting the lock off as the hatch overhangs the lock by about 3".

[ 03-09-2005, 08:06 AM: Message edited by: uncas ]

[Ian McColgin]

There is no excuse for a sliding hatch that will fail the firehose test from front and/or sides. The aft end is a bit hard to fully water-proof unless you go in for a bit of trickery above the barge boards.

The yard is right about the front. A turtle is the only way.

There are quite a few ways to make the sides resist boarding water. By the way, it need not be from a wave. Sailing to weather in a hard driving rain will get through most common not-ready-for-offshore hatches.

There are many good hatch designs. One classic used on the companion of my old Alden schooner Goblin was a husky bit of bronze half round screwed to the top and running along the sides. It's diameter was about 1-1/2 times the thickness of the hatch allowing the lower side of this C to ride in a groove on the side of the hatch's combing. I really could play a hose against this and water would not get in.

G'luck

[uncas]

Ian...Have never tried the fire hose test...All I can say...my hatch does not appear to leak...Now you are right...There is potential on the campanionway end...I will just hope that when I have a tail wind, a fire hose isn't part of the mix... ;)
Then again, if I am running down the bay with a tail wind and a fire hose spouting water from behind..I'm gonna be out of luck anyway as my hatch boards would not be in place...
Anyway...back to the theme...
Good luck and I hope you find a plan or two which will work.
jamj

[ 03-09-2005, 08:35 AM: Message edited by: uncas ]

[Bruce Hooke]

It seems to me that a key question is how leakproof do you need the hatch to be. I sailed the length of the US eastern seaboard round trip in a boat with a sliding companion way hatch and no garage/turtle and I never found leaking from the front to be a big problem. BUT, I stopped pretty much every night and did not sail in storm conditions. If you are planning to sail offshore that is a completely different situation. And I should note that "offshore" includes coastal passages where the distance from one harbor to the next means you might get caught out in heavy weather and have to ride out the storm.

[uncas]

Bruce...interesting point...Have sailed under varying conditions...And have actually found that those going up and down the campanionway in bad weather... for a break...and thus opening the hatch puts more water below than the weather/wave/etc does.

[ 03-09-2005, 09:15 AM: Message edited by: uncas ]

[sgunns]

The scale of boat is probably important. She is a 59ft on deck and 74ft sparred length bermudan ketch. (She was originally gaff but I decided it was too hard). Our initial planned trips would be to Tasmania and NZ,and could include 10 days plus at open sea with all chances of weather.

The decks are flush except for a small raised doghouse aft. I was planning a dodger, but would have to remove it in bad weather, before it removed itself.

In Bass Straight I would like to have minimal water below from the companionway hatch. The boatyard suggested total covers over the doghouse, that could help to keep the varnish. But trying to integrate covers with dodger etc may not be easy.

Now my predicament may be clear.
Steve

[Ian McColgin]

By covers to protect varnish I take it you mean cloth snapped on. Yeah. Fine. I've seen boats kitted out with covers for everything including combings and toe rails. The local canvass guy must be a heck of a salesman. But these do not enhance the seaworthiness of the hatches.

Except in special cases. I had leaky hatches on Goblin at first. Geoggous mahogony hatches with nice round portlights in the center. They leaked at the seams and under the bronze of the port lights. So, until I had a chance to rebuild the hatches, I put a bit of sheet plastic under the cloth covers when it rained.

But back to your lovely sounding boat, make the turtle for the companion slider. It's then easier to make the forward lower attachment for any dodger you make anyway.

Many boats of this type have a companion that goes down to a kind of standing area anyway. It may be quite easy to arrange either a panel or what amount to shower curtains on either side to keep any rain and drippings from wet oilies in one place.

A trescool wrinkle is to have the cabin sole have an eight inche by eight inch or so grate at that point. Let the water go straight to the bilge without puddling. If you have a fitted tin, like a brownie baking pan, racked under there, you can sweep out the boat without bothering with a dustpan.

But to return, the turtle over that hatch will protect against boarding seas and will keep the hatch from being ripped right off in a real plunger.

I assume you have other hatches. One hopes they all have their hinges at the foreward edge and utterly reliable ways to be dogged down. All hatches must be operable from inside the boat.

If any hinged hatches are simply a lid with down facing sides on a combing and if there is space between the hatch cover and the deck, boarding water will sluice right in under there. It should not be hard to plane the under edges of the lip flat, slight down slope out. Then fit some wood to the deck outside the combing that comes up to meet the lip with the barest gab - really no gap when the hatch is well dogged against whatever you have as gasket at the top of the combing-hatch cover boundry. That will keep a boarding wave from getting under there.

You don't have to go far to need good hatches. In Nantucket Sound where the plan was Osterville to Vinyard Haven in the usual southwesterly but running a solid Force 8 gale we got a lesson. I had been annoyed by Goblin's leaky forehatch and wondered about the gap between hatchcover lip and the deck but had done nothing about it.

We got very hard smacked by a steep rogue that tore that hatch right off and sent it surging along the side decks. We were lucky. My crew grabbed the hatch as it surged past the cockpit while I paid off. We still took a couple of thousand gallons of water. It's incredible how much water there can be in a boarding wave. Wallowing along on an easy reach, we nailed the hatch back on, pumped like blazes for nearly an hour - this with a 2" Edson that really can move over 50 gpm - and gradually recovered our equinimity. Ever since that and learing how the Sophia went down, I've paid very close attention to hatches, especially on the foredeck.

Batten down.

G'luck

[ssor]

Check out the hatch construction on the pilot cutter. Might be just what you want.

[outofthenorm]

Tasmania? New Zealand? 10 day passages? Man I'd fit a good stout turtle over that hatch and be happy as heck. You could plank or paint the turtle so it looked just like the deck and it would be almost invisible. A turtle also makes a dandy place to keep a throwable life ring that you can reach in mere seconds.

Your boat sounds a beauty. Any pictures?

- Norm

[Andrew S/Y Rocquette]

Steve

I'm currently restoring a 1964 C&N Rocquette (http://www.yacht.ro/frame.php?lang=en&linc=race) - I managed to find mmost of her orginal plans through Jeremy Lines (ex-head designer at Campers) and from the National Maritime Museum at Greenwich, which holds most of the Campers and Nicholson's archive.

Have you tried them for the original plans which you can then amend/adapt from?

Cheers

Andrew
S/Y Rocquette

[sgunns]

Gentlemen, Thanks for further responses. I will try and cover my latest thinking. The aesthetics of my project are paramount, and by adding a permanent solid housing for the hatch to slide in adds bulk to the appearance. That is why I do not wish to go that path.

Canvass covers appear to be the only method of keeping water out, however they also protect the varnish which is an added benefit.

I have now found an answer that offers the best solution. Most external traditional hatches seem to have the track onto which sits the sliding hatch. The Fife Astor currently in Oz has fitted a pair of external timbers adjacent to the track and with tight joinery, that appears to stop most side water access. At the front, I was considering a multi-tongued junction to minimise the chances of water enrty. All this will still have canvass covers.

I can psot a photo but do not know how. If someone can let me know I would appreciate it.

I have had many convsersations with Jeremy Lines, and have the original plans from the NMMuseum in London. However no detail plans are on record.

Thank you,
Steve