E41 Fresh Water Tank Leaking

Hello all.
I have a '68 41'. I've developed a leak (crack really) that I can barely see in the centerline fresh water tank. I had been noticing a lot of expansion/contraction noises in the tank while filling or using water. This last time, I think the hose pressure was pretty high, and I filled it to the brim. Now I have fresh water trickling into the bilge.

Has anyone replaced or accessed this tank before? There are no obvious hatches in the floor to get where I believe the leak is. I can contort my hand and arm to just feel where the leak seems to be coming from behind the V-drive. The tank feels like thin steel to me. Is that right?

I'd really appreciate any suggestions or insights.

Smooth seas,

Dave Schile
Stormy Weather
Ericson 41'
Roche Harbor, Washington.

Since nobody else answered you, I'll take a stab. When filling water tanks on old boats that have little or no access, it is prudent to make sure the vent lines are clear and the hose tap is set to trickle.
If you shove a hose into the fill and turn it on full blast, you run the risk of blowing out a tank seam. The first system into the hull after the ballast was the water tanks, and then the pan was dropped in
and glassed. Tank replacement usually means cutting up the pan. I'm not sure what your tanks are made from, but it's very likely they are welded aluminum. If it's leaking bad and you don't want to hassle
replacing it, your other option is a tank in a new spot, like under a berth. Keep us posted.

Martin

I had a similar water tank crack due to a clogged water tank vent 3 years ago. the clogged vent caused the tank to flex, and a crack to develop. the rest of the tank was fine, with no cracks. After I cleared the vent line, I installed a SeaBuilt Tank Access Plate above the crack to gain access into the tank. I successfully welded the tank using a $180 airless plastic welder-5600ht(www.urethanesupply.com). I was able to weld a 1.5 foot long crack using the plastic circle I cut out for the access plate as "welding rod" material. I was careful to heat the weld all the way thru to get a true weld, and it hasn't leaked a drop since. I practiced on different plastic objects and was able to successfully weld the tank the first try. As a bonus, I also now have a cleanout access plate for the water tank.

Hi Dave,
My '68 41' no longer has the centerline freshwater tank, possibly due to cracking. The PO placed two large lockers where the tank was, one with a water maker. I also hear some "oil-canning" or expansion/contraction sounds from the starboard tank when it is nearly empty and then when filling and it is nearly full. I checked the vent and cleared it which stopped the sounds.

Dan
Magic
Ericson 41'
Shilshole Bay Marina, Seattle