question about clogged seawater intake on CD25D marine head

[gmills]

I've experienced a problem with the operation of the marine head on our 1982 CD25D. There's a significant backpressure with the handpump on the upstroke , when I try to operate the pump handle to bring seawater in (on the upstroke) and then flush fluid to the holding tank (on the downstroke), and no seawater enters. The tank was recently pumped out. We use the head only for liquid waste.

My guess is that there's a blockage at the seawater intake (marine growth, barnacles, etc.). If so, where on the hull is that intake located? Are there other possible explanations for this problem?

Thanks in advance for your help!

Greg Mills

[mgphl52]

A long time ago we quit using raw water to rinse the head.
Instead we pump fresh water from the basin for the rinse.
This has cut down on head/holding tank odors immensely!

[Sea Hunt Video]

Greg:

There is (or should be) a raw water seacock in the forward cabin where the head is located. On my CD 25D it is located in the forward cabin on the port side forward. The intake hose runs from the seacock to the marine head. From the outside the thru hull should be about 2 feet back from the bow and more or less 1 foot below the waterline.

[Dick Kobayashi]

For now i suggest you flush with sea water from a bucket, doesn’t take much volume. My guess is that the prob is in the pump mechanism and that you wiil need to take the pump apart and may be replace some parts, but since a repair kit is $100 you might as well replace all. While the boat is in the water skip examining the water intake——too much effort.

[gmills]

Thanks to those of you who've responded.

I'm still trouble-shooting this issue. I located the seawater intake (thanks to Roberto's reply) and did some scrubbing from my dinghy with a still-bristled long-handled brush. This didn't seem to have any effect. Next I'll try Dick's suggestion of flushing with a bucket of seawater, before focusing on the pump mechanism itself.

The good news is that the boat is sailing well, and we're enjoying some late-summer breezy conditions on Vineyard Sound!

Greg

[gonesail]

if you have an external strainer .. as my boat does .. it can get clogged up with barnacles and growth .. especially in the warm summer water. same with an engine cooling water intake.

[kerrydeare]

... still trouble-shooting this issue. I located the seawater intake ... and did some scrubbing from my dinghy ... didn't seem to have any effect ...

If you cannot either dive under or haul the boat, try this.

Close the head intake seacock. Disconnect the intake hose from the head (usually just a single stainless hose clamp). Feed the disconnected hose into the head, a bucket, or the bilge if it reaches. Then open the head intake seacock.

At this point either there is, or is not, water flooding in through the hose. Most likely not (more below), but if there is, the issue is not the raw water intake but the hand pump on the head itself. This will require a re-build which is not all that difficult, but must be done precisely and carefully. Parts are usually outrageously expensive (but then no one forced you to buy a boat).

If OTOH there is no water ingress, you can try a more drastic approach that, while unlikely to sink the boat, usually results in an extended clean-up session, so don't wear your prom gown. First, close the intake seacock and remove the intake hose from the seacock fitting. Then take either a wooden dowel or a reasonably stiff soft (non-metal) brush or something quite similar and get ready to hustle. Maybe even have a soon-to-be-lost friend standing by with large old towels.

Open the seacock (now exposed to the outside water) and start forcing one of the above-mentioned tools through the fitting. Keep at it until there is (tons of) water coming in. Then close the seacock, reconnect all hoses and devices, clean up the wet cabin, and go sailing. Maybe even buy your friend a beer to repair what's left of the friendship.

If none of this works, you can do what I did recently and sell the darn boat. My new boat (AKA Honda Accord) has none of these issues.