transom flap seals

[Obscured by clouds]

After sailing the Merlin back to the beach as a semi-submersible because of severely leaking transom flaps it bacame obvious that the seals need replacing. What was there is foam draught excluder, probably put in 25 years ago.

I'm assuming things might have moved on since then so what is everyone using these days. Tell me it is'nt draught excluder.

[Rupert]

Vaseline?

[Garry R]

The Enterprise I sold the guy at Forfar had the same problem. Seems it was best solved by sitting furhter forward in the boat and getting the transom above the waterline.

[Ancient Geek]

Garry is right if you are putting any part of the transom under the water at all you are sitting too far back or are too heavy for the boat!

[Ed]

True, but if they are a bad fit, then by the time you have put the rudder in....you already have enough water and weight in the boat to make it hard to keep the transom free....and then more water gets in.....and it just goes from bad to worse.

Lots of ways of making transom flaps seal properly, but it does depend on the type of flap, so you may need to send a photo.

If they are fitting into a rebate in transom, then sometimes some form of foam tape has to be used to bring them up to the right level....or some thin neoprene.

Otherwise, a smear of silicon put on and allowed to go hard can work well if you can get it nice and flat.

But in the end, none of these methods tends to be very good.

I have often worked on the principle of using some tape on them to stop water ingress when it isn't very windy and therefore unlikely to capsize. If I capsize, I pull off the tape and use them. Chance are that it is then windy enough to use the flaps and self-bailers.

cheers

eib

[alan williams]

Hi Throw them out, cover the holes with fablon. When needed pull off fablon. Replace after use.
This is the method I've used for years sailing a Hornet with out any problems it also saves weight at the end of the boat.
Cheers Al.

[jon711]

We used to use Fablon on the Enterprise, and they are one of the better options. Just need to make sure that the varnish is well attached. We did kick the Fablon out once, and took a HUGE chunk of varnish off the transom, I was quite surprised that Fablon sticks better to varnish, than varnish does to wood!!!! (I suppose that the same could be said for Duck Tape on the bottom of the flaps - never tried that, but seen it used!). The best transom flaps I have seen are a flexi-plastic - P&B sell it...

http://shop.pinbax.com/index.asp?select ... le=Perspex Sheet for Transom Flaps 18cm * 50cm

I seem to recall they seal pretty well to a smooth surface, may be a help?!?

Jon

[Michael Brigg]

I have never sailed anything that uses transom flaps however I would envisage you need something to line the edge of the flap to give a good seal, soft enough to fill any irregular contours.

I recall seeing two main designs;

1.)Inverted cones (usually small fuel funnels) on shock cord. The cone fills the large bung hole which is lined with a suitable rubber gasket (Neoprene I would guess.) Release of the shock cord lets the "bung" go and weight of water pushes it out in the manner of a one way valve.

2.) A "Cat flap" type of door opening outward. Again, controlled by a suitable spring return, with the door being lined with a suitable soft gasket. The strength of the return spring seems to be critical. To strong, and it doesn't open. To weak and it leaks. The art is to have a gaskett that works at minimum pressure, or an easily adjustable return spring. Shock cord and a small cleat on the hog under the tiller would seem logical.

Where the "Cat flap" demands a period feel it is perhaps made in the manner of a little fairy-door, out of wood, with elegant hinges. If more modren, a clear plastic construction might be better.

Some boats have flexible bendy plastic, like the centreboard flaps, and no hinge is required. Simply cut to shape and screw in place along the "hinge" edge. The problem is it gets brittle and breaks at awkward moments (like the final beat on the have to win race)

As a robust alternative I would suggest the material often used for a computer mouse mat. It often has an ideal soft grip-mat undersuface, and is usually made of a robust plastic material. They are also cheap and easy to find.

For a gasket I would suggest the soft stickyish rubbery material sold in chandleries to stop your dinner plate sliding off the galley table. Perfick!

Either material could be used as a liner for the more esoteric wooden flaps sported by the more gentlemanly conveyances.

[Ancient Geek]

The one thing Transom flaps are not is "period" they are as newer than me, in general application although the principle was understood, many UK Classes legislated against them, MR's Int 14's etc., in any practical size untill 1965, when the Merlin Rocket Class, experiemented with them, and the late great David "Ned" Sparrow fitted a set, as an experiement for the class, and on one of the many cancelled days at the 1965 Championships ( I was robbed!) went for a sail in the Cattewater at Plymouth capsized on purpose and arose from the sea like something from Pirates of the Carribean, we were "sold" on the spot the rule change was passed "nem con" at the AGM that evening!
Lest the Catflap anagogy give the wrong idea the hinges or hingepoint must be vertical and adjacent to the rudder otherwise when open they will restrict rudder movement.
I have never "got" the leak issue they do not let much water inanyway (how long for goodness sake does it take to fit a rudder?) and crews are emp loyed to sponge boats dry anyway! If you are of the Garbo persuasion and want to sail alone then it's just another thing to pass the time sponging out the dregs!

[jon711]

I must agree, and disagree with AG. Yes, it can not take long enough to fit the rudder (or rotate the rudder to the down position), unless you have a really S**T system, to ship much water..

The crews job (You knew this was coming!!), is to keep the boat level, sheet the jib, tell the helm where to go (In the nicest sense!), sort the c/board, look after the kite.... And NOW we are expected to bail the water out as well!!! (As well as cunningham, kicker, and on some Merlins avoiding the mainsheet track (Got the hint yet DavidH!!))

I admit crews in the 1950's were expected to bail, at Hunts I crewed ina boat built inthe 1950's and althought the boat leaked, the self bailers were enough to keep it dry..

As an ex semi-pro crew, I do get annoyed when we are treated as bailer operators!! (Sorry getting off the Soap Box now!!)

Jon

Not sure if this is trail thread, if so sorry Ed/Neil

[Pat]

Our Merlin flaps are single sheet of clear thin perspex I think about 1.5mm thick. The sheet is flexible, covers the full width of both holes and the pintle area and hinged purely by being attached at the centre with a couple of screws. Two fine holes in each of the sides are threaded with elastic which pulls the flaps shut and loops to a hook about a foot inside the transom.
The modern Lark has two smaller transom holes and we have two flaps each somewhat bigger than the hole and held in place with the same elastic arrangement and, I think, a bit of tape at the top of each. The flaps were cut from the flexible lids of trade buckets of paint.
We've had hinged thick perspex ones and the hinges fail and the perspex deteriorated and cracks. Softer ones seem to fit better but they all leak a bit if you get back in the boat e.g. to put the rudder on.
"Evicting the passengers" as we call it is the crew's job on a quiet leg - getting self bailers open if possible or just scooping it out. Then we hit a gust or a bad tack and scoop in a load more!

[Ancient Geek]

Thank for that support Pat as to labour division in a dinghy! There is a shortge of good Dragon Crews travel the world and sail free!
I am the first to say good crews are essential and they must be "clubbable" too if you can't have a giggle and share preducices is there any point? Take it very seriously yes, but if it's not fun why?
To return -sort of- to topic best Transom Hole Protectors (They were hardly flaps.) I ever saw were on Keith Mustos final Flying Dutchman - the holes were protected by red and green spinnaker nylon attached by velcro on three sides and permenantly on the other, but then Keith like most good sailors would not expect to capsize much if at all.

[Michael Brigg]

At the risk of a rap on the wrist from the moderator for trolling...

Roger said:-

Jon the man is mending the boat as his on the ground hobby. He cant sail though I have offered to teach him.

"Eats shoots and leaves" is the title of a book about use of punctuation, and the sad demise of this skill (even in those schools that OFSTED marked as Outstanding enough to apply for foundation status)

What Roger seems to be saying here is that: "Jon (the man) who is mending his boat, (presumably the one he broke at Whitefriars) can't sail, and needs lessons.
Roger, who I think sailed with him, has offered to teach him!!"

Have I read this correctly?

Perhap, Roger, you could teach him how to bail!

Whitefriars11[1].jpg

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[Garry R]

Of course Gannet, Secret Water and Iska being of an older generation don't have transom flaps and rely on a single bilge pump (brass) as permitted by the class rules of the day (1946-1951) which is used to get rid of surplus water operated by crew or helm depending on position. Once capsized it's prety much game over - no self bailers either. I have to say I was tempted to put them in Gannet but then thought that it would be a shame to cut two holes in the hull of a 59years old boat so now sail somewhat defensively. As for transom flaps - no way!!

[Garry R]

I have also found that using the bilge pump on a genlte breeze run alongside a Laser has often upset the concentration of the Laser sailor. There he/she is, sailing along in the plastic indestructible and supersuck bailer available only from the Laser supplier (including replacement high cost spring) with an ancient Merlin alongside. Suddenly the Merlin helm or (for the sake of equal rights and PC) crew begins to pump his (or her) arm vigorously up and down. The next thing to happen is a stream of water peeing out of the side of the boat midships giving a gentle broadside of water. Mirth all round. Jokes about incontinence and prostate trouble abound. Laser sailor has concentration broken, Merlin sails through!! Magic.