Transom Flaps

27/07/2009 09:39:39
Peter 3112
This is possibly a stupid topic but I have only recently felt sufficiently 'competent' to sail in stronger winds than Force 4 - an inevitable must do this 'summer'. Consequently, sailing my NSM yesterday in squally conditions, although very exciting, meant that we occasionally shipped (scooped in!) a bit more water than the self bailers could remove quickly. So should the transom flap elastic be tensioned so the flaps will open when there is just a bit more water pressure from inside than outside the boat or am I expected to judge when to open them manually?

27/07/2009 13:00:28

On our NSM2 the flap elastic is adjusted to keep the flap flat (they're flexible).
This keeps 99% of the water out when launching. If you fill the boat with water, there isn't enough pressure differential to open the flaps - it's a manual release. You can have another control line to pop the elastic from the hook (if you want another piece of string) - or just release manually.

You need not pull them closed until you're about to beach.

It is worth making sure that with the flaps fully open you can still move the rudder stock fully! I've seen some flaps that will restrict the movement when fully open.

Colin (3387)

27/07/2009 15:05:09
Peter 3112
Thanks Colin,

I will see whether there is scope to tie an extension on the existing loop in the elastic to prevent them flapping round far enough to foul the rudder stock. All we needed yesterday was more rapid draining of the slightly swamped boat than the self bailers achieved.

At the moment I have hinged 3mm polycarbonate flaps but may go for the flexible type that I saw on the new boats at Ally Pally - for a significant weight reduction!

Hope you are having a good season.

27/07/2009 16:09:51
Andy Hay - Enchantment 3386
We use the mylar film, double sided sticky tape along inboard and top edges with the bottom free. No elastic, rope or otherwise. Haven't noticed much water coming in when I meander to the back to pop down our fixed rudder and that's with 14 plus stone wandering about like a lost elephant. Very light, very simple, very cheap and no moving parts to go wrong. If only the rest of our Merlin was the same (broke her on Sunday, so in a bit of a grump) :-((

Mylar stuff and the tape from Northampton Sailboats or maybe P&B if I recall.

30/07/2009 23:28:55
Can anybody recommend anywhere for suitable mylar film, nr Southampton please?

31/07/2009 09:50:25
JohnB (3404)
I use the 1mm perspex that I got from Tony Blackmore at Sailsport. 4mm bolts will hold it in place and its flexible enough to bend without needing hinges.

Tony might be able to advise if you are set on Mylar.

[email protected], Tel: 01392 420043/07977 512673

If you use the perspex, cut it with scissors, not (as I did) a jigsaw.

Cheers, John


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