Shower won't drain

[Pete G]

I just bought my boat and have an issue with the shower not draining.  I ran a large zip tie (didn't have a snake handy) down the drain hole and it was blocked.  I'm not sure if there is a fitting that needs to be opened - looked under the bathroom sink and the kitchen sink but didn't see anything resembling a valve.  There's no access under the two teak/holly panels between the shower and the galley - floors are solid.   I assumed it would drain to the bilge, but the bilge is dry.  Can anyone shed light on the layout of the plumbing?

Pete
Maris Otter
1987 Tall Rig

[robbjd]

On our 97 34Mk2 there is a pump under the galley sink that drains the shower. There is a switch for the pump located above the toilet.

[pbyrne]

On our 97 34Mk2 there is a pump under the galley sink that drains the shower. There is a switch for the pump located above the toilet.

Yes, for a MKII, under the sink there are valves that are marked to determine which 'pipe' the pump under the sink will pull from, and out a thru hull that is also under the sink.  There is a breaker that needs to be thrown, and then the switch in the head, above the toilet, needs to be activated.  That will active the pump under the sink and suck all the water out of the head.

If it's blocked look for a config similar to our MKII's.  Not sure about a MKI which based on the age I presume you have.

[waughoo]

Your boat being a mk1, the pump is in the compartment under the sink.  There is also likely a check valve in that system.  I found that my diaphragm pump was pretty stiff and had debris in its check valves that caused it not to be able to move water.  As others have said, this isn't a gravity feed system.  You'll need to trace the hoses and start checking for obstructions.

[Noah]

In the MK1,  I recommend cutting a hole under the floorboard into the liner (and install a Beckson port recessed so flush mounted) in order to reach the shower drain hose connection. There is also a check valve in that line. I cant find my photo of how I did mine but Jon W. may have a photo of mine and his. I slso changed that pump to a better shower sump pump, not the original diaphragm one.

[mark_53]

Your boat is an MK1 so plumbing is different than MKII.  I had similar problem.  I had a Jabsco check valve before the anti-siphon valve.  Check that the direction of flow on the check valve is correct.  The Jabsco check valve has a logo with an arrow but the directional arrows are on the valve are different.  Don't be fooled by the logo.

[Pete G]

cutting a hole under the floorboard into the liner

Any advice on the location of the hole?  How thick is the liner? 

[Stu Jackson]

You could also, dare I suggest, look in the manual for your boat.  If you don't have a hard copy, guess where you could find one.

I have a Mark I, I've replaced the check valve, system works just fine.

[Ron Hill]

Pete : The diaphragm pump to your shower drain for a MK I is under the HEAD sink near the rear of that compartment.  There is a 5/8"? hose from the drain to the pump and in that line is a one way valve (to prevent back flow) that is probably clogged with fuzzy wazzys and hair!! 

Open the head sink door and you'll find that line laying on the hull.  Don't pull too hard on that line so you preclude pulling the hose off the drain connection and creating ANOTHER problem - causing you to have to cut thru the flooring to get at that drain connection!!!

I wrote a couple of Mainsheet tech note articles about how to install a filter and a new back flow valve in that line for a MK I shower drain system!!   

A few thoughts

[Noah]

The hole is only needed if you want to change the hose connected to the shower pan drain. You can reach check valve by just removing toilet paper cabinet or perhaps through the sink door? . No other way I know of to reach the drain end of hose on a MKI. Cut as close as you can to reach it from the outside of the shower door. A 4-6in. Beckson port will work to fit your fist through to reach barb. Liner is probably 1/4 in. fiberglas?

[pbyrne]

This topic gets me thinking... there seems to always be standing water in my drain, and it looks pretty manky.  Drains fine when operating.

What's the approach to change the hose on a MKII while we're on the topic.  I don't see a way to get to the fitting in the floor of the head...

[Pete G]

I have the original manual.  Many things on the boat are not original.

You could also, dare I suggest, look in the manual for your boat.  If you don't have a hard copy, guess where you could find one.

[Jon W]

Here's 2 photo's of Noah's access hole in the subfloor to get at the drain hose connection under the showerpan. I haven't cut a hole yet. If/when I do, I'm leaning towards cutting the hole in the showerpan. Have to be careful because there's a lot of stuff under there, but think it will give easier access and it's a non-structural surface.

[Noah]

THX Jon!

[rmjohns]

On the Mkii at least, Catalina fiber-glassed tubes to the underside of the floorboard and ran the fresh water hoses inside those tubes. When I cut an access hole to get to the shower drain pipe I nicked one of those fresh water lines and had water shooting at me. I about had a heart attack until I heard the fresh water pump start running and I realized what I'd done. Hitting water when you're cutting the floor of your boat is a bit concerning.