Dinghy drain

[azuredragon]

I’m considering getting a double hulled plastic dinghy. The model I’m looking at does not come equipped with a drain. Since we store the dinghy on davits overnight it needs to be self draining. The inner hull has a seat moulded across the transom so the distance between inner and outer skin is roughly a foot. Has anyone installed a thru transom drain in this type of construction?

My idea is to install a round access port in the top part of the seat to provide access to both inner and outer skin. Then possibly small thru hull fittings to inner and outer skins and connect them with a piece of tubing. Fit the inner one with a rubber bung.

Anyone have experience with this situation?

[bobat2]

Hi Azure Dragon,

Our Walker Bay 10 (WB 10) has a similar double-molded, maybe foam filled rear seat, and their setup is a tube that goes through the two hulls, thru-hull style, then has an external drain plug, tethered to a cord. In the tube is a one-way flapper and seat that allows interior water to drain, sometimes seep out, but prevents water from flooding in, should one forget the external transom plug. If one needs it drained in a hurry, it can be propped open from the inside with a stick, twig branch, or dowel; however, be sure to paint it or flag it with a bright color, so it is not forgotten upon launching. I was also told by an inflatable owner that as soon he gets the dinghy up to speed, (XX fossil fuels XX), he pulls the internal drain plug, and the boat self bails. (I am afraid that wouldn't work at my rowing speed.)

Also, the floor/sole design of the WB 10 is such that the protrusion of the external keel/skeg is reflected on the inside, creating a valley/trough to channel the interior water toward the drain tube. Our dink is in storage, surrounded by snow, or I would send you a picture.



Hope this is helpful,
Bob
Plainfield, VT

[azuredragon]

Thanks Bob. Great info.

[Manateeman]

Electrical supply stores have bulkhead fittings which have NPT female threads on both ends. You can make up any sort of pvc glue fittings or pipes and thread that into the bulkhead fitting or use a pipe plug or a rubber stopper.
There are nice stainless dinghy self bailing devices I think made in Europe...like Anderson self bailer will work too...we have them in our Trinka dinghy and love the big Anderson which works very well.
Offshore we leave open a big stainless screw out plate if we are worried about rain or storms.
That’s in the transom but the Anderson is at the low point..no plug to loose either.
They will drain the boat if the dinghy hull speed is good.
Great for washing out pizza crusts and spilled beer from my manatee crew.
Happy trails.
Captain Mark

[rslifkin]

The Andersen bailer is a good idea. I've been wondering about popping one of those into the bottom of a dinghy near the transom...

[AKA-None]

I wonder if that space is air tight and considered part of the flotation if the interior is flooded?
In which case make certain you don’t compromise it