Sealing anchor hatch on old boat

[Andysdad]

Hi,

Firstly, thanks to everyone here - the effort, expertise and emotion people put into their boats is inspirational as well as better than watching anything on TV!

As a counterpoint to everyone else's perfection - here's my request for assistance.

I have an old boat (18' half cabin with a new engine - see my other thread! :facepalm which serves us very well here in Oz. She's about 40 years' old, beat-up and does not leak a drop (now that I put stoppers in the fishing rod holders the PO fitted to the gunwhales.....). She may be old, but 33Kts is fine for us.

Motor is worth $10K, boat with motor is worth $9K, you get the picture.

The anchor hatch is a simple clamshell (wider at the rear than the front) over a lip on the deck (Photos 1 & 2). The lid/aperture has a 1/2" gap across the front so any wave over the bow enters the cabin fairly directly! (Photo 3). The sides of the lid are bowed-in (Photo 4) and grip the aperture at the midpoint (see diagram in photo 1) but have a small gap either side of that. The rear edge of the lid has a reverse-sloping piece that seals pretty well.

Viewed from inside looking forward (photo 5) you can see the uneven vertical and horizontal gaps between the lid and aperture.

So, my big problem - how to seal the hatch? I tried a simple gasket of silicone on the lid inner to meet the lip edge, but cannot do this accurately enough, so one point always lifts. The lid is not flat, the aperture lip edge is not flat and the existing strap does not pull down evenly or hard enough anyway.

I thought to put a lip seal horizontally around the aperture edge so the lid folds it down when closed. This may work on the front edge but not the sides (not enough clearance).

Current madcap idea is to cover the aperture lip with vaseline and with the lid lifted just a fraction at the front (0.01mm! and sealed with vaselined tape outside), squeeze lots of silicone into the gap from the inside.
Then smooth the inner edge whilst wet and leave it to set. Should separate OK once set and I razor off the external excess flush to the lid edge. The new tie-downs would compress the seal into place. Or not?

I don't want to spend much (if any!) money on this, I have time instead. The boat is not worth $300 for a new hatch plus the odd-shaped hole makes this difficult.

I know I need better latches - maybe the rubber toggle types on the inside (we rarely anchor!) to hold the front corners down better. Can anyone suggest an alternative that can be opened from both sides of the hatch?

All suggestions gratefully received!

Thanks in advance.

A

 

[Grandad]

Re: Sealing anchor hatch on old boat

Hi Andysdad. I don't think that hatch will seal effectively using a single latch. Fortunately the hinges appear mounted near the corners, which is a good start. The other 2 corners need to be independently latched. Trying to add or replace deck hardware isn't done cheaply usually, unless you can find a boneyard to scavenge, but it'll take time. I'm not sure I could dream up a latch that would open from either side as you desire. That said, you might used a relatively inexpensive pair of stretchy rubber T-handle toggles that stretch into metal sockets mounted inside. Something like this: Latch Rubber Draw T-Handle Porsche Part Distributed By Patrick Motorsports

Once mechanically secured, I think I'd then try to find a suitable rubber seal to glue to the lid. They're not expensive. No seal will fit well if you don't get those corners fastened down first. - Grandad

 

[britisher]

Re: Sealing anchor hatch on old boat

Get hold of some car door rubber weather seal. You can buy universal online and in auto stores or you can get hold of some from a car junk yard. It's usually designed so that it sits over the metal seams of the door aperture. For your situation the metal door seam would be your vertical lip on the hull aperture. Once installed (sharp knife and rubber mallet), you'd clamp the lid down as normal and the rubber would snug up against the inside of the hatch cover. Hey presto - waterproof. It would also make that seam a lot less lethal looking too.
Hope this helps.

 

[Woodonglass]

Re: Sealing anchor hatch on old boat

Here's How I'd do it. The sealing lip/surface is very thin. I'd make it wider by using 1/2" aluminum angle strip and riveting it to the inside edge of the hatch opening and contact cement a piece of rubber seal on top of the angle to seal the lid when closed. Like this...

 

[Andysdad]

Re: Sealing anchor hatch on old boat

Grandad - those are the rubber toggle type I mentioned. You are correct that fastening the front corners is important to a solution.

Britisher - I considered boot (sorry, "trunk" - but you''re British so will know what I mean!) seals but there is not enough clearance at the sides and the variation in height is too much.

WOG - thought of that and bought the materials then realised it won't work as the lid is too uneven plus too little clearance at the sides plus the anchor chain will destroy it.

Sorry to be so negative to everyone's suggestions - I've tried a few so far but bouncing more ideas around helps though!

Will try the silicone/tape/vaseline on Friday after we sail tomorrow; I think it will work and if not, it's only $7 a tube.....

Thanks so far

A

 

[jbcurt00]

Re: Sealing anchor hatch on old boat

Bump

 

[Andysdad]

Re: Sealing anchor hatch on old boat

Bump

Thud - had no time to go ahead but am thinking of making two twist handles for the hatch(1 per front corner).

Watch this space.....

 

[jbcurt00]

Re: Sealing anchor hatch on old boat

It didn't click originally when I read your thread, but would a large silicon rubber half round gasket applied to the lower portion of the hatch, where the operable portion closes down on, seal against that lip & seal as you need?

Bud (CC254) made his own hatch gaskets out of silicon in a mold.

I'm not sure what he used to attach them to the inside of a hatch, but I do know he was very pleased w/ how the gaskets turned out. The details are buried in his SeaHawk thread. He's not been on much in a LONG time, but you can scan his thread &/or PM.

SmokeOnTheWater knows him, so if you don't reach Bud in week or after a couple of tries, you might ask Kevin (Smoke) to try & reach him for you.

Most of the details are in there, so you may not need to reach Bud anyway:
CC254 - 1990 254 Sea Hawk

 

[Andysdad]

Re: Sealing anchor hatch on old boat

jbcurt00 - many thanks for taking the time to post that. I had seen Bud's original post and looked it up - my problem is that even the deck edge is not uniform and the cover is crazy wonky!.

Started tonight on making corner handles/clamps that will cinch down the hatch at each front corner. Then I will adjust them to be loose and do what I posted earlier - vaseline the deck lip, tape the outside part of the hatch to stop squeeze-out of silicone, and then simply fill the gap from the inside. Let it set, knife-off any surplus and then re-tighten the clamps so it pulls the cover down onto the lip and the silicone does the rest. Fingers and everything else crossed!

Spend so far $31......will post photos when it's light (now 2100 here in Oz).

Thanks again.

A

 

[Bondo]

Re: Sealing anchor hatch on old boat

Ayuh,.... Lookin' at yer pictures,... It appears to Me,....

That if ya shimmed up the hinges a slight bit, the front edge would lay down, Much closer to closed than it is now,...
It appears to be bindin' on the aft edge of the deck flange,...

 

[Andysdad]

Re: Sealing anchor hatch on old boat

Bondo - thanks for that - you're right but the hinges are riveted-in and removing and raising them would be messy. The lid is not flat anyway so there will always be a gap at one end or the other.

Anyway, I think I've done it. Not the best or tidiest job in the world, but total spend $37 and I think all I'll get is a few drips coming through.

I made handles from aluminium 1" square tube (on special so $1.50 per 2' length), filed a square hole to take a s/s coachbolt so turning the handle turns the bolt. Then underneath the hatch more 1" tube as a latch, cinched into place by double-nuts locked onto each other, packing inside the tube to stop it crushing and a nylock nut on the other side; high torque squeezing the latch stops it rotating on the bolt. Finally a spreader bar to stop the two sides bending inwards towards each other. See pic 1.

The "seal" (I use the term very loosely!) was done by taping the aperture lip with masking tape (helped clean-up a lot) covered with vaseline, lifting the hatch slightly and firing silicone into the gap. Once dried it fits where it touches and the handles compress the rest into place (sort of). See pics 2 and 3.

I could tidy up the silicone on the outer side but I don't want to mess-up the seal line.

I know I have let down the standard of fine workmanship everyone expects here on iBoats but I just want to sail it (without sinking.....)



Thanks everyone for the advice; even if it is rejected it is certainly appreciated and all advice helps to narrow-down a solution.