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Old 25 March 2005, 06:30   #1
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Searider - Flooding Hull / Transom Flap

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
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Old 25 March 2005, 06:40   #2
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have a look at your local sailing club

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
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Old 25 March 2005, 06:56   #3
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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 . . .
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Old 25 March 2005, 15:29   #4
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Don't mess it up.....That's my favourite ever Searider!
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Old 25 March 2005, 16:02   #5
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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?
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Old 25 March 2005, 16:54   #6
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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 ?
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Old 26 March 2005, 08:13   #7
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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
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Old 27 March 2005, 14:44   #8
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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...
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Old 28 March 2005, 12:49   #9
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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.
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Old 28 March 2005, 13:45   #10
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Hmmmm

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.
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