Aft Water tank - aft wall in aft berth (a lot of afts)

[Baysider]

Going into our fourth year with our 1990 C34 we keep running into unusual situations.  Our aft water tank's vent stopped working. No whistle, no water, so the tank overfilled. It seemed more reasonable to approach the tank from the rear berth as there is too much above it including the propane tank box.  But in addition to the screws holding up the aft wall there are three or four which are only accressible from behind the wall.  Is this normal or could it be a PO's doing?  I tried with no luck to sneak my hand in through the plastic cover and screw them out.  Any suggestions? 

Also, any suggestions regarding access to the vent line?

Finally, it may be that water from the overfill worked its way into the berth as the aft, port, corner of the mattress was wet (our C34 leans to port).  Is it possible that overflow worked it's way in?

[Noah]

In addition to the front screws with their finishing washers, there should also be ONE (factory) screw from the backside at the top holding the aft bulkhead in. You should be able to reach that through the cutout in the top of the bulkhead once you remove the fiberglass idler wheel cover. Any other "backside" screws (if they exist) must be a PO addition. You also could have spiders or other critters nesting in the vent line? Try blowing out with compressed air?

[Ron Hill]

Bay : When you are removing that aft teak panel and the cover over the bottom of the steering WORD of CAUTION!! 

There are 2 lengths of screw so when you take things apart make sure that you note which screws came out of where!!  Because if you reassemble with the longer screw in the teak panel - owners have screwed a hole in their water tank!!!   

A few thoughts

[pbyrne]

Removing the cover over the bottom of the pedestal/quadrant idler wheels leaves a small gap in the teak that will allow you to put your hand thru with a screw driver, and unscrew the panel by hand. At least on a MKII.

Looks like this was standard practice with Catalina.  Very frustrating and I never put them back after removing them.  The front facing screws are plenty as far as I can tell.

These screws are screwy!

[Jon W]

Baysider, as Ron said be careful when reinstalling the screws. Last thing you want is a self inflicted leak in your water tank that is not easily repaired. I replaced the screws with SST T-nuts and SST machine screws cut flush with the T-nut. Then for added protection I taped over the T-nuts with 20mil PVC tape.

While you are in there - Look at the pins in the Edson steering idler pulleys to see if they are brass. If they are, they have been known to break so remove and check them closely for wear. If in doubt replace them with SST pins from Edson.

[Baysider]

Great input from all.  Thanks!  I removed and reinstalled the screws last year when I first had tried to remove the panel.  I truly hope I didn't puncture the tank.  I guess I'll find out if I can get the panel off.  The problem is still the 4 screws coming in from the rear.  My arm doesn't want to reach far enough to remove them.  I'll give the compressed air a try as well.  Last year I tried to suck out whatever might have been in the vent using a Shop Vac.

[Noah]

Wow! FOUR screws from the back? Hard to imagine that was factory?!? No need for that! Thinking out-of-the-box, worst case is to cut the notch in the bulkhead bigger so you can get you arm in there, and then recover with a piece of teak or a new larger idler puller cover box made of teak? You can never access that bulkhead through the aft helm hatch with watertank in there. Curious; you say 1990... do you have a traditional straight transom, a sugar scoop transom, or a walk-though transom?

[Baysider]

Hi Noah.  It's sugar scoop.

[waughoo]

Sugar scoop?  You got one of the rare ones!!  I know of three now: yours, Noah's, and Patches'.

[Baysider]

I'm happy to be one of few!

[scgunner]

Baysider,

I'll start with your last problem first, aft cabin corner leak. The aft water tank sits on a fiberglass base which is tilted rearwards which allows water to collect there if there's a leak. When on a port heel the water runs to that side which allows it to drain forward into the aft cabin. Aside from fixing the leak I had in my tank I drilled drain holes in the back corners of the base. Now should I get water there it drains to the bottom of the boat and runs to the bilge.

Regarding the aft tank you can't really overfill it when it's full water just runs out the vent in the cockpit. If the vent is blocked the water will just run out the fill up on the side of the boat either way you shouldn't be getting water inside the boat. If the vent is blocked you'll also have another problem. With no vent to equalize pressure in the tank a vacuum will be created and you won't be able to get all the water out of the tank. If that's the case you can remove the tank fill cap to act as a vent until you get the problem solved.

I have no idea why there would be mounting screws behind the bulkhead or the purpose for them so that's likely a PO thing since we boat owners have a tendency to over engineer things. But once you do gain access the fix should be simple since the vent system consists of a nipple on top of the tank, a section of 1/2" hose, a couple of clamps and the vent fitting in the cockpit.

[Nicholia]

Kevin, I've been perplexed by the water running into the aft cabin from the vicinity of the water tank, but have not been able to sort it out.  When you say "leak" - do you mean a leak from the water tank or a leak from the deck?  Mine seems to have to do with a leaky port light in the cockpit - this porthole has been minorly leaking into the aft cabin (onto the mattress naturally), but when I put tape over the porthole for that issue it seemed to maybe? solve my leak down the aft bulkhead (though maybe I have not heeled enough to port to test it - I had not known what provoked the water intrusion into the cabin ....).  But honestly that did not make any sense to me.  Yes, I need to rebed that port light, but it sounds like you've been down this road before so I'd love to know what you know about where the water comes from.

Thanks, Brenda

[scgunner]

Brenda,

I've been down this road so many times they actually named it after me! We're talking about two separate leaks. The port light leak will drop water directly onto the cushions or bedding and is a problem you'll have to address separately. The rear left corner leak is caused by water build up in the water tank support base and leaks when the boat heels left. I found the water from this leak usually doesn't wet the cushion but gets underneath it which is just annoying. The water build up I got was caused by a water tank leak but could also be caused by any water leaking into that area such as leaky scupper hoses or anything else that allows water to collect in the tank pan.

If you drill drain holes in the tank support base that will keep the water from getting into the cabin but you'll probably still want to find where the water is coming from (in my case the tank). Regarding the port light problem I fiddled with the Becksons for years and finally replaced them with Lewmars. Along with solving the problem the Lewmars are flush so you don't kick your ankle against them like the protruding Becksons.

To address the rear corner leak the procedure is as follows. Remove the rear wooden bulkhead, drain, disconnect and remove the tank then you can check the tank pan to see if it's wet (it shouldn't be) and drill a couple of drain holes in the rear corners of the pan.

[Noah]

For those who would like a photo of what's behind the curtain, this is what the water tank installed and removed look like.  Perhaps there is a bit more going on in my boat due to my below deck autopilot.

[Ron Hill]

Noah : Thanks for the photo, as I didn't realize that the configuration of the aft water tank was that different from that of the 1987 thru 1989 standard transom C34s !!

Thanks,  Ron