Transom Flap help required

   Hi, I am replacing a transom flap on my 420 and have purchased a sheet of thin Mylar which came with a roll of double-sided tape. 
Is the idea to use the tape just along the top of the flap so it can swing open when under pressure from water from the inside? And if so, is it likely to stop water coming IN from the outside?

Or is the idea to tape it shut completely and punch it open when there is too much water for the self-bailer?

Any assistance very much appreciated.

Cheers
Sean

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spookysean Send Private Message Find Member's Posts Newbie Joined: 13 Jul 11 Online Status: Offline Posts: 2	Post Options Post Reply Quote spookysean Report Post Quote Reply Topic: Transom Flap help required Posted: 13 Jul 11 at 3:27pm
	Hi, I am replacing a transom flap on my 420 and have purchased a sheet of thin Mylar which came with a roll of double-sided tape. Is the idea to use the tape just along the top of the flap so it can swing open when under pressure from water from the inside? And if so, is it likely to stop water coming IN from the outside? Or is the idea to tape it shut completely and punch it open when there is too much water for the self-bailer? Any assistance very much appreciated. Cheers Sean

Roger Send Private Message Find Member's Posts Visit Member's Homepage Really should get out more Joined: 23 Mar 04 Location: Somerset Online Status: Offline Posts: 524	Post Options Post Reply Quote Roger Report Post Quote Reply Posted: 13 Jul 11 at 5:01pm
	Your first comments are correct, just fix it across the top, as you say internal water pressure will force it open and any external pressure will just force it to close and stop water entering the boat... Well thats the theory anyway.....

Jon711 Send Private Message Find Member's Posts Far too distracted from work Joined: 04 May 07 Location: United Kingdom Online Status: Offline Posts: 465	Post Options Post Reply Quote Jon711 Report Post Quote Reply Posted: 13 Jul 11 at 11:36pm
	Personnally, I prefer fablon, that you kick out with a foot, after a capsize (I don't do them!), and then replace the fablon between races. More watertight, and depending on how often, (Or rarely!!) you capsize can work out cheaper. On a GRP boat I would always opt for fablon, however, when I was wooden Enterbox sailing, it did tend to remove varnish!! Failing that hinge at either the top or the middle (Very little difference, in performance), but add some duct tape on the lower edge, to stop water entering the boat when tending the rudder during launching... If the hinged flaps are preffered, I have been told that Overhead Projector Film is very good, but I have no first hand experience of this.... Jon
	Blaze 711

spookysean Send Private Message Find Member's Posts Newbie Joined: 13 Jul 11 Online Status: Offline Posts: 2	Post Options Post Reply Quote spookysean Report Post Quote Reply Posted: 14 Jul 11 at 9:10pm
	OK, thank you, gentlemen, I shall give it a try. Cheers for your help.

winging it Send Private Message Find Member's Posts Really should get out more Joined: 22 Mar 07 Online Status: Offline Posts: 3958	Post Options Post Reply Quote winging it Report Post Quote Reply Posted: 21 Jul 11 at 9:28am
	these things are the bane of my life. Unless you do as Jon says and stick them up permanently until you push them out, there is no really effective way of keeping them shut so they keep the water out. On a grp boat like a 420 I would definitely go down the tape/fablon route and never use them unless you have to - they're pretty useless as baliers anyway. Both (!) my current woodie phantoms have the hinged version and I am probably going to use thin perspex along with rubber draft excluder stuff to try and make them water tight. I don't like to tape them because it pulls the paint off!
	the same, but different...

Jon711 Send Private Message Find Member's Posts Far too distracted from work Joined: 04 May 07 Location: United Kingdom Online Status: Offline Posts: 465	Post Options Post Reply Quote Jon711 Report Post Quote Reply Posted: 21 Jul 11 at 10:52am
	If you are thinking about the foam draught excluders, don't bother, they just do not work, and end up letting more water in, than if they had not been fitted. On a woodie, really strong shockcord, stiff flaps, and grit your teeth a bit of tape at the bottom (Insulation tape, may leave paint/varnish intact)
	Blaze 711

winging it Send Private Message Find Member's Posts Really should get out more Joined: 22 Mar 07 Online Status: Offline Posts: 3958	Post Options Post Reply Quote winging it Report Post Quote Reply Posted: 21 Jul 11 at 11:23am
	.....and just don't capsize! cheers Jon!
	the same, but different...

Graham T Send Private Message Find Member's Posts Visit Member's Homepage Posting king Joined: 09 Apr 07 Location: United Kingdom Online Status: Offline Posts: 123	Post Options Post Reply Quote Graham T Report Post Quote Reply Posted: 21 Jul 11 at 10:35pm
	On my woody Osprey I just have really flexible plastic clamped in the middle with the rudder fittings. If I am at the stern sorting the rudder water pressure alone clamps them closed enough not to leak. No elastic or seals needed. I think this is only possible as the plastic is very flexible. I have no idea what the plastic is as I picked up a load of offcuts out of a skip.....
	Osprey 55 "Tebutinnang" Osprey 1245 "Two Bob Bit" Miracle 1358 "Thumper"

JMORRISSEY Send Private Message Find Member's Posts Newbie Joined: 18 Oct 15 Location: MANCHESTER Online Status: Offline Posts: 30	Post Options Post Reply Quote JMORRISSEY Report Post Quote Reply Posted: 31 Oct 15 at 7:05pm
	Can anyone help with my 420? I have the same issue. but i am restoring it and have a big hole in the rear. as seen below... It had a piece of perspex bolted over it. Should it have some sort of flap? What to buy to get it to work? Or should I just close it up with GRP?
	Here goes my learning to sail midlife crisis