I took my 7.7m out on the weekend and while at a marina, noticed the boat took on a large amount of water. This boat has a fairy decent bilge pump, Seacock drains and also these odd one way hull drains
Its an aluminum hulled RIB. When I got it on shore, I took the cover off one of the drains and noticed it had failed.
<a href="https://ibb.co/jf7ywDp"><img src="https://i.ibb.co/zxKX2Zk/Hull-Drain-2.png" alt="Hull-Drain-2" border="0"></a>
Essentially its a hole in Aluminum on an angle, EPDM with a stainless block attached covers the hole and is attached above it. I assume if water pushes from the inside, the EPDM pushes away from the Alum Hull and the water escapes.
When water pushes against the hull from the outside, the EPDM seems to block the drain hole.
In this case the 9 year old EPDM failed. The Stainless weighted block fell off and the water rushed into the holes until the boat had a lot of water in the hull.
I'm looking at these drains wondering how common they are ? They seem very simple and almost risky if they fail ..
The Decks on this boat seem to drain into Drain cocks. These drains seem to simply let excess water out of the hull.. is this common ? Do I need them ?