Scupper cover flap question

[salar]

This is the stern of my Harley 25 motor cruiser. The cockpit deck is about 10 cm above the waterline and drains through the transom through a couple of large holes. These holes are covered on the outside by these simple plastic hinged flaps (I have seen identical flaps fitted to Avors). The transom is angled slightly so the flap doesn't hangle closed. All good except when going hard astern where the water pushes the flap up and floods the cockpit floor. Also at anchor fishing, if the wind is on the stern I get a slop through the scuppers in the same way. Is there a better scupper cover than this available? I have searched online and all drains and covers seem to be much smaller. Or any DIY ideas? I thought of a bungee to hold the flap closed but that seems a bit Heath Robinson.

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[NormanS]

What about drilling a hole through the centre of the flap, and inserting a suitable sized bolt with a nut on it, from the outside, and fastening it with a nut on the inside. The weight of the bolt will keep the flap normally closed.

 

[KevinV]

What about drilling a hole through the centre of the flap, and inserting a suitable sized bolt with a nut on it, from the outside, and fastening it with a nut on the inside. The weight of the bolt will keep the flap normally closed.

That would work. Perhaps gluing a round piece of stainless or lead would be neater than a bolt?

 

[Refueler]

Why not fit a valve in the drain line ?

My cockpit drains are similarly just above W/L, when motoring or healing under sail - I can get water come in. The solution was to fit handy ball valves in the drain lines.
I always know when I've forgotten to close on departing berth - I get wet feet !!

What about drilling a hole through the centre of the flap, and inserting a suitable sized bolt with a nut on it, from the outside, and fastening it with a nut on the inside. The weight of the bolt will keep the flap normally closed.

I think OP's transom will not be vertical when underway ... so flap even with added weight will not close.

BUT - what about the Cat Flap idea ? Magnet ? Suitably placed magnet(s) just inside scupper pipe and corresponding on the flap. Just enough to hold flap closed - but water can still escape by 'cracking' the flap open ? Such method could be completely hidden.

 

[KevinV]

I think OP's transom will not be vertical when underway ... so flap even with added weight will not close.

It's not vertical at rest even, but weight added "outside" a vertical from the hinge line will push the flap beyond vertical to close against the hull as intended

 

[salar]

Thank you, good ideas but I think it needs to "spring" close very firmly. The transon isn't vertical, and the flap is lifted when wave or wash hits the stern and water is forced upwards. Magnet might work though?

 

[andsarkit]

You could fit a drain with a valve and fit removeable bungs in the existing drains. Drain or ping pong scupper



I have a similar problem with my cockpit drains and considered adding floppy tubes to the outlets as seen on some RIBs.

 

[GunfleetSand]

Thread resurrection

Same problem in a Hardy fisher @salar did you find a solution?

Do the flap type scuppers have an internal non return valve?