CS20 bilge modification

[wkisting]

The last two weeks before I resume teaching are always the most productive boat work times for me.    I finally solved a pet peeve I've had since we built our CS20 that might interest some of you, or maybe it doesn't bother anyone else.

 

When I finish sailing, there's always a pool of bilge water (~ 2 cups) that collects alongside the keel batten in front of the CB case. I usually notice it as I put the boat in the garage, then bruise my stomach/ribs leaning hard over the coaming to mop it up with a towel. It will not evaporate on its own. (I once neglected to mop it up and found the water still there a week later.) So, I shaped a board that fits alongside and blends into the keel batten to fill in the low spot from the forward bulkhead to the CB case. Now any forward bilge water runs across to the opposite side of the keel batten and runs aft, where it is much easier to sponge up or vacate through the Anderson Bailer. This mod also created a wider flat spot for the cooler that rides under the thwart and provided a great, discrete place to install an electric bilge pump (where it can't get kicked or broken off its mount easily).

 

I decided to add the bilge pump after getting caught in a storm this summer. I had to go ashore to wait out the lightning. When the torrential rain finally let up, it had filled the cockpit with 6 or 7 inches of water! The bailer was able to deal with it, but it took quite awhile and the many gallons of sloshing water as I tried to sail in the blustery and rough conditions were a little disconcerting (the bailer needs a hull speed of at least 3.5 knots to work). An electric bilge pump could've drained the boat without even leaving shore, or would've helped the bailer drain the cockpit over twice as fast. To keep things simple, the pump connects by a short length of tubing to a CPVC fitting that turns 90 degrees, runs through the top front of the CB case, and turns 90 degrees again to empty down inside the CB case (via the gap just ahead of the centerboard). I like this setup because it requires no exit holes in the outer hull and minimizes how high the bilge pump needs to lift the water.

 

 

[Garry]

Nice solution!

[Docpal]

Wes,

 I was in touch with Graham about a similar plan last week, and he suggested I incorporate a "vented loop" into the discharge side to prevent back siphoning, but it looks like your method might eliminate the need for the loop since you are on the center line and about as high inside the boat as one could get without needing to drill a hole into the hull.

[wkisting]

it looks like your method might eliminate the need for the loop since you are on the center line and about as high inside the boat as one could get without needing to drill a hole into the hull.

 

Yep, I'm convinced a vented loop is not needed in this position. I can't imagine any scenario in which the exit port would be under water (unless the boat has sunk!). It also minimizes the amount of tubing needed for the bilge pump, and no need to run it through a seat locker and out the hull.Note that to accommodate the mounting, my bilge pump's exit port connects to tubing that promptly spirals about 120 degrees (putting a lot of compression on the no-kink tubing, though not enough to close the passageway), then runs up the front angle of the CB case, turns 90 degrees, goes through the CB case via 1/2" i.d. CPVC tubing, and turns 90 degrees again. Those abrupt turns and the slight shrink in diameter to 1/2" i.d. tubing probably restrict the flow a bit, but I tested it several times and the flow looks really healthy. I would guess I'll get at least 400 gph out of this 500 gph-rated pump. Plenty for my needs.

[wkisting]

Here's a pic of the bilge pump from the other side, plus a pic of the switches I installed in the seat faces. Top one is a master battery switch. Bottom one turns on the bilge pump. They light up blue (LED) when activated.