CD30 - installing an auto-bilge

[Kickin Bears]

I’m working on an auto-bilge installation for our CD30. Right now there is only a manual bilge pump installed, useable from the cockpit

However, I need some ideas / guidance on how to run the line. I was thinking I’d just install a Y-valve and switch between the two as needed to avoid having to add another through-hull. After reading through numerous posts on this topic I see that there are many recommendations to skip the Y-valve and add another through-hull

Has anyone added an auto-bilge to their CD? How did you run it? Any issues or considerations I should take note of?


For reference:

ABYC Section “H-22.8.8" states:
"If the discharges of several pumps are manifolded to discharge through a single thru-hull fitting, the system shall be designed so that the operation of one pump will not back feed another pump, and the simultaneous operation of each pump will not diminish the pumping capacity of the system. A check valve shall not be used in the manifold discharge system.”

See also ➥ Manifolding Multiple Bilge Pump Discharges

[gonesail]

on my boat the bilge pump hose exited the hull well above the waterline. no need for a sea cock or a check valve. so you could run the new line wherever you needed to. measure 5 times .. drill once.

[Kickin Bears]

I assume your setup has anti-siphon setup for the hose? Any issue when heeling if / when rail hits water?

[Carl Thunberg]

My former CD30 would siphon exactly the way Steve Laume described in another recent topic. My common sense solution to the siphoning problem was to switch the bilge pump to OFF under sail. No more siphon because the bilge pump never kicked on while heeled. Just remember to turn the switch back to ON when you are done sailing. This approach only works for day-sailing or coastal cruising. I would not do it offshore.

[Steve Laume]

I sailed with only the original manual bilge pump for years. I try for redundancy in all critical systems and dewatering the boat seemed to fit into that category. I wasn't interested in an automatic bilge pump. I have some thoughts on why they are not necessarily a good thing but will not go into that here. I did feel that I needed a, permanently mounted, back up for the manual and that it should be a, high capacity, electric, pump. My reasoning was that if I had water coming into the boat, my time could be better spent than sitting in the cockpit, pumping the bilge.

I went with a Johnson 2200 Which is mounted to a teak board, epoxied into the bilge. I chose to modify the bottom of the engine cover to accommodate the extra hose, along with the original bilge pump and sanitary hoses. I mounted the through hull as a mirror to the original and gave the hose a high loop before exiting. It is wired to a dedicated breaker for manual switching only.

I was aware of a possible siphoning issue and would not feel comfortable with my set up if the pump had an automatic feature. I did mess up once while well off shore and sleep deprived. A lot of water can come in a hose that size. You don't tend to see where it is coming from either as it exits in the bottom of the bilge. I had a clear hose and finally noticed the bubbles, once I had pumped out the bilge and shut the pump off again. Simply standing the boat up a bit, stopped the problem. I know never to pump the bilge with the electric pump when on a port tack. The manual bilge pump will not back siphon. A vented loop would solve everything but I have been unable to find one that has 1&1/8" hose barbs.

If you are going to have an automatic switch, you need a vented loop. I would never trust myself to rememeber to turn it to the off position every time, Seve.

[Kickin Bears]

Really good info Steve. Did you post a vid with the epoxied board setup? If so, I think I watched it and am planning on using same approach.

Plz feel free to PM me your thoughts on auto-bilge issues. I’d love to hear them.

The manual bilge pump has worked well, and after researching various auto-bilge setups, I’m more on the fence about the install than I was a few weeks ago

I’m not crazy about putting another hole in the boat, but also not crazy about using a single outflow line too. At this point, I’m not even sure the benefits outweigh the negatives re; an auto-bilge, though I do like the peace of mind in a redundant electric bilge pumping water while I go below deck and determine leak root cause

Electric bilges existed in 1982 didn’t they? I’m trying to understand Carl Alberg’s reasoning for not including in the design

[Dick Kobayashi]

Suggestions based on my 25d


Run a separate hose of largest feasible diameter to high up on the transom and put in a dedicated thre hull.

Put highest capacity pump for the line in the bilge

Wire it to a switch that has a continuous setting as well as a”run while pressed” setting.

Forget about automatic or float switches if I staled you will never know your boat is taking on water.