Searider - Flooding Hull / Transom Flap

MikeCC · 25 March 2005, 11:30

I have a 5.4m Searider which originally had the bow holes and stern drain hole blocked. However, water was getting into the hull somewhere and, of course, couldn't get out again. (Interesting effect on performance!)

Really I should find out how/where the water is getting in, but that's bound to be a fairly time-consuming (and possibly fruitless) effort.

To get round thr problem and avoid too much water getting into the hull, my thought was to use a transom flap of some sort. Having looked over previous threads on the pros and cons of the hull design, I couldn't see any mention of whether anyone had tried this.

I wasn't thinking of anything fancy - just a hinged flexible flap which at rest would hold to the transom by water pressure. On the move, any water in the hull would just push out.

An enhancement would be to add a release mechanism of some sort to enable the hull to fill if the extra stability was needed.

Has anyone tried this? If it worked OK, what was the construction?

Any suggestions please?

Thanks

Mike

matiboy · 25 March 2005, 11:40

see how the dinghies use different variations of transom flaps

if only a small bit of water getting in each trip , easier to fit a drain bung

if a fair bit of water getting in then maybe an inspection hatch at rear combined with bilge pump

if lots getting in then you might as well go back to draining flooding hull as before . only find this is a pain when launching as boat doesnt float off trailer so well on certain slipways

MikeCC · 25 March 2005, 11:56

You're right - the launching bit was exactly where the idea started.

Variations on dinghies might be OK although they often use lightweight materials/fixings which might not last long at 30knots!

I was avoiding a pump installation - just wanted to go for a simple solution.

Having thought further, I do recall one mention of a neoprene flap being used. I guess it could just be held in place at the top with a strip of stainless screwed on. Should work as long as the fixing point was far enough above the drain hole to allow the material to seal around it. Now, where's that old wetsuit . . .

Rogue Wave · 25 March 2005, 20:29

Don't mess it up.....That's my favourite ever Searider!

MikeCC · 25 March 2005, 21:02

Stuart - Yes, we talked on the phone about the hull filling up a while ago. Call me lazy, but the investigation just seemed like a headache.

Boat not wrecked but quite a few bits and pieces to sort out. (Electrics a bit suspect, extra seat, possible move console forward, gluing various bits back on etc)

Any ideas for a flap of some sort?

Rogue Wave · 25 March 2005, 21:54

Hi Mike

It's easier to talk than write, so call me if you want! But you won't be able to get away with a flap that will withstand the water pressure as the boat goes through it would need some sort of Cam to hold it in place. Or the lid and neck from a small flare pot.

Didn't it have an insopection plate blocking off the hole and didn't that have a small bung in it! what wrong with replacing /resealing that system?

Is your trailer bunked or roller ?

MikeCC · 26 March 2005, 13:13

The original inspection hatch/bung could be re-fitted/sealed but I'm not 100% that is where the water comes in. So the idea is to minimise the water coming in with a flap of some sort but allow any coming from elsewhere to push out easily.

I'd expect the flap just to be fixed at the top edge. It dowsn't need to be down while on the move - just the opposite in fact.

The trailer is a roller type.

Mike

lc0021 · 27 March 2005, 19:44

If it's of any interest, it is possible to biy a ready-made flap like what you describe. I bought one from Polymarine last year - it came in 4 parts - a through - transom fitting (mine was about 2.5 inches in diameter), two flaps, one neoprene and one was some kind of (silicone) rubber - and a plastic cap. the caps and flap snap together and attach to the through hull fitting via the reatining screws. As far as I remember the whole lot cost less than a tenner - and looks better than homemade...

MikeCC · 28 March 2005, 17:49

Quote:

Originally Posted by lc0021

If it's of any interest, it is possible to biy a ready-made flap like what you describe. I bought one from Polymarine last year - it came in 4 parts - a through - transom fitting (mine was about 2.5 inches in diameter), two flaps, one neoprene and one was some kind of (silicone) rubber - and a plastic cap. the caps and flap snap together and attach to the through hull fitting via the reatining screws. As far as I remember the whole lot cost less than a tenner - and looks better than homemade...

Thanks - that's exactly the sort of thing I had in mind. Seems the one you have is the only size. Unfortunately the hole in the Avon is around 105mm diameter.

The Bryster · 28 March 2005, 18:45

Sounding interesting.
I've sealed up my hull for this year (see pix), because the boat is used everyday and lives on the water. I've also bolted on a set of Hydro-foils on my engine which have made the boat much more trimmable whereas before trimming up made absolutely no difference at all.

However, with there being a fair few fittings bolted through my transom, there is a small amount of water seaping into the sealed compartment (from somewhere!).

I pump this out through the bung hole in the top using a cylinder type pump, but this flap system sounds like it would save me from this chore.

I have used an old piece of Alloy deck track about 7" long (from a yacht) and tapped an 8mm hole through the middle of it. On the outside of the hull is a piece of marine ply with a hole through the middle which my bolt goes through to screw into the Alloy bar (with lots of Duralac) and clamp the hole shut with plenty of jollop! My breather holes in the bow are filled with Silicone.

A flap system sounds neat and it is used on small rubber dubbers too.

lc0021 · 28 March 2005, 21:14

Quote:

Originally Posted by MikeCC

Thanks - that's exactly the sort of thing I had in mind. Seems the one you have is the only size. Unfortunately the hole in the Avon is around 105mm diameter.

mmmm.... If you're very handy - there might be a way you could fabricate something very similar in that size... It's really BIG - almost the size of a CD - or even - domestic sewer pipe... If you go to a DIY/Hardware store - you can buy a bung for closing off a domestic sewer pipe. If you can neatly trim the shoulder off it - then you have the plastic disc part. Now you neet to get the two rubber flaps.... it's pretty easy to get hypalon or PVC from which to cut the thin flap - and I'm pretty sure it's possible to get a price of neoprene from somewhere who makes/sells/repairs wetsuits, etc...

Dunno - seemed like an idea - if you have the time & patience.... Might be something else there in the domestic waste area that I've missed!!!

Pete7 · 31 March 2005, 10:06

Although the Poly Marine one is only 68mm dia why not glass in a ply fillet and mount one of these at the bottom of the ply.

http://cat.polymarine.com/acatalog/P...ailers_10.html

Pete

MikeCC · 31 March 2005, 11:23

Thanks for the various suggestions.

I'm trying to get the best all-round arrangement:
- a dry hull while launching to help with floating off the trailer
- the option to flood the hull at rest if wanted
- quick dumping of water when moving off

I think the Polymarine unit might be a bit restrictive when dumping the hull water. A 105mm hole is 2.5 times the area.

Will try the simple flap idea and see how it goes. As long as outside water pressure is enough to seal even with some water ingress, it should be OK.

I could always lift the flap and put in a bung if required.

Mike