Transom flaps...sealable?

[Greenheart]

This isn't a joke to wind Lakesailor up. None of my pre-launch queries are, but the longer we have to wait for spring, the more there'll be...

My transom flaps look like a couple of bits of cut-up milk-carton, connected to the boat with white parcel tape...

View attachment 30486

...and since I'm new to the boat, I'm in doubt of their watertightness, especially as it's likely I'll be out in a force-nil the first couple of times...

...if the flaps only drain the boat when moving (because she wasn't designed for idling or anchoring) I reckon they'll leak in waves. Not that I intend making her stern drag in the water...but don't any manufacturers of inspection-hatches, also make transom-shutters which can be sealed in the shut position?

 

[yoda]

It looks like the shock cord that is attached to them is quite loose, and by applying tension the flaps will close against the hull. I don't believe you need them to seal that well but just stop the majority of a wave coming in. This is quite a normal arrangement. If you feel the arrangement is a bit Heath Robinson then some flaps manufactured from acrylic with nice hinges may smarten up the appearance.

Yoda

 

[FistralG]

If you are planning on racing that arrangement is far too heavy.
In my dinghy racing days we covered the hole with sticky back plastic and kicked it out when the water in the bottom of the boat got too deep.
Cheap and easy to replace when necessary.

 

[mjcoon]

If you are planning on racing that arrangement is far too heavy.
In my dinghy racing days we covered the hole with sticky back plastic and kicked it out when the water in the bottom of the boat got too deep.
Cheap and easy to replace when necessary.

How much water in the boat does it take to be heavier than a flap that seals properly?

Of course comfort (dry feet) could be higher priority than maximum speed...

Mike.

 

[humbug716]

The transom flaps I use on my Osprey are similar. I use light plastic taken off an exercise book and replace every season. The shock cord needs to be just tight enough to keep it flush against the transom. When I end up with a boat full of water (quite often) as soon as the boat starts moving the pressure just folds them back enough to empty the boat quite quickly. You might need new shock cord or a little more tension.

 

[Lakesailor]

OK,
it'sSolo which is a smaller boat, but my flaps were well clear of the water when sailing. Lots of modern boats don't have a transom.

It's sunny today. Get it in the water.

 

[FistralG]

How much water in the boat does it take to be heavier than a flap that seals properly?

Of course comfort (dry feet) could be higher priority than maximum speed...

Mike.

A little water in the boat will be heavier than flaps but the dinghies I raced had self bailers to deal with small quantities.

The transom flaps only really got used after a capsize or if the boat was swamped by a large wave.

Most of the time the flaps (as Lakey points out) are clear of the water.

Dry feet in a dinghy...it rarely happened as I launched off the beach so wet boots kept my feet warm but never dry.

 

[Deleted member 36384]

They can be made from stiffer material such as perspex attached with a hinge and a strip of neoprene used to create a seal. The shock cord is then pulled tight to hold the flap closed and released when large amounts of water need to be dumped. This modification is usually on dinghies converted for cruising.

 

[Greenheart]

They can be made from stiffer material such as perspex attached with a hinge and a strip of neoprene used to create a seal. The shock cord is then pulled tight to hold the flap closed and released when large amounts of water need to be dumped. This modification is usually on dinghies converted for cruising.

That's what I had in mind...but who makes them?

 

[jimi]

That's what I had in mind...but who makes them?

You do ;-)

have a look at this thread http://www.gp14.co.uk/forum/forum_view.php?message_id=322

 

[Deleted member 36384]

That's what I had in mind...but who makes them?

As Jimi says. I have cruised on a few old racing dinghies and they were all home made jobs. The hinges were usually poor designs, the best were solid plates with an inner raised lip that fitted through the profile on the stern and secured the plate within the transom hole. When the bungee was released they just fell out and got dragged a wee bit behind the yacht. The plate and lip method is very simple with no drilling, no recesses for hinges or stupidly small screws to handle. Works well without hinges.

 

[akyaka]

OK,
it'sSolo which is a smaller boat, but my flaps were well clear of the water when sailing. Lots of modern boats don't have a transom.

It's sunny today. Get it in the water.

Thats an interesting mainsheet arrangement. Any particular reason for it rather than taking off at the centreboard casing

 

[Lakesailor]

Standard Solo mainsheet.
It gives you a mainsheet traveller which those who race will be able to explain much better than me.
It's to do with maintaining the sail shape you want (flat/full) whilst allowing for the wind strength. I think.

Anyway that's all I managed to achieve with it.

When I could remember....... and had enough spare hands.

 

[lw395]

One of my boats has transom flaps of 1 or 1.5mm polycarbonate sheet. No hinges, it just bends.
You can always tape them up on light days.

 

[dunedin]

If you are planning on racing that arrangement is far too heavy.
In my dinghy racing days we covered the hole with sticky back plastic and kicked it out when the water in the bottom of the boat got too deep.
Cheap and easy to replace when necessary.

+1. Sticky plastic is much the simplest and lightest solution on most dinghies, and as you say kick out if needed (typically only after a capsize). The older style rigid Perspex and shot cord may be necessary on Osprey if it has a stern deck

 

[EuanMcKenzie]

My mark 1 had and open transom. Having almost sunk on a downwind leg in light conditions and sloppy seas it was time to block the hole.

cut transom shaped flaps from 3mm perspex and drill to hold shock cord retaining line. cover the transom holes in cling film then create a seal with clear bathroom sealant between flap and clingfilm. it should then take the unevenness out. once dry rip off what you can of cling film and refit the flap. If the shock cord is not to stiff and you have self bailers as well that should see you right as they will bounce to let big slugs of water out the rear when your going fast but stop dribbles filling the boat when you're going slow.

if you can't be bothered with all this then tape them up and fit a bigger self bailer or a bucket. £1 from B&Q

 

[akyaka]

Standard Solo mainsheet.
It gives you a mainsheet traveller which those who race will be able to explain much better than me.
It's to do with maintaining the sail shape you want (flat/full) whilst allowing for the wind strength. I think.

Anyway that's all I managed to achieve with it.

When I could remember....... and had enough spare hands.

Yes understand the principle but think its upside down. No wonder we've given up racing for leisurely cruising


http://www.solosailing.org.uk/uploaded/gallery/1188_burghfield01.jpg

 

[Greenheart]

My mark 1 had and open transom. Having almost sunk on a downwind leg in light conditions and sloppy seas it was time to block the hole...cut transom shaped flaps from 3mm perspex and drill to hold shock cord retaining line. cover the transom holes in cling film then create a seal with clear bathroom sealant between flap and clingfilm. it should then take the unevenness out. once dry rip off what you can of cling film and refit the flap.

That sounds like the best answer, thanks. I'll test the existing arrangement soon, and change it if it's less than ideal.

 

[Lakesailor]

Yes understand the principle but think its upside down. No wonder we've given up racing for leisurely cruising

Oh! I see what you mean. I was just trying the mainsheet with one less component to see if the balance between higher loads/less sheet to handle would be manageable.

It wasn't. The loads were too high. Went back to normal.

 

[DanTribe]

When my son was 17, he sailed a Lark which he named Damp Flaps.
I always assumed that it referred to these devices but he later told me that the name had sexual connotations!