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replacing fiberglass fresh water tank
Posted: Wed May 05, 2010 10:30 pm
by CaptMike
Hey there all,
I have a 1991 10.8 meter express with a huge fiberglass tank in the middle of the hull in the cabin. There is a leak somewhere in the fresh water system that fills the bilge where the shower pump is and the fittings for water pump etc. I know it is the fresh water system as I died the fresh water and the bilge filled with dyed water. Now, I ruled out the shower, head, faucets, sink etc as everything around there is dry. I shop vac the bilge dry and don't see any drips coming from the fittings that are obvious... In fact, it seems that there is a leak origination from under the tank. There seems to be layers of fiberglass where the tank rests and water is penetrating a layer and then filling the access hatch... All dyed green though when i tested so I am confident there isn't a serious thru hull leak or something of that nature...
Anybody have this problem... I ready to cut out the tank myself and replace it with a plastic tank as I think I have ruled out all other possibilities of leaks with the dye and that fact that other fittings and appliances etc are dry that I can see.
Posted: Wed May 05, 2010 10:41 pm
by Big D
Wow, cutting it out seems kind of extreme. Fibreglass is very repairable. can a large access hole be cut in the top in hopes of finding the problem and fixing it from the inside?
Posted: Thu May 06, 2010 6:10 am
by RWS
have you tried to see if the leak changes when the fresh water system is pressureized vs. not?
RWS
Posted: Thu May 06, 2010 7:15 am
by CaptMike
when the water pump is on the tank seems to drain faster... The pressure switch on the water pump is broken too... Also, the forward bilge fills first then moves to the mid bilge because they are connected though a drain hole in the bulkhead. I can't find any links in the tank fittings or any leaks from the shower, kitchen faucets or head sink lines... All of those areas are dry.
Posted: Thu May 06, 2010 8:07 am
by ready123
CaptMike wrote:when the water pump is on the tank seems to drain faster.
That one thing alone would move my attention away from the tank. I would suggest you have a downstream fitting or cracked hose downstream of the pump. In my opinion a leak from the fibreglass tank is very unlikely.
Posted: Thu May 06, 2010 9:21 am
by CaptMike
I would tend to agree with you, but I just can't find the darn leak. All of the access panels I pop open are dry... Not sure how I can get to the leak if there is one I can't see. I suppose I will keep looking.
Posted: Thu May 06, 2010 10:21 am
by ready123
Not familiar with your boat but it sounds like you have hidden runs of the pipe.... luckily I can see all mine on the F32 though some spots require me to crawl in some small spaces and look behind wall structures.
How cost effective ($$ and mental stress) would it be to run new hose for those points you can't get to and then splice it in to replace suspect lengths?
Posted: Thu May 06, 2010 10:24 am
by ready123
CaptMike wrote:when the water pump is on the tank seems to drain faster... The pressure switch on the water pump is broken too... Also, the forward bilge fills first then moves to the mid bilge because they are connected though a drain hole in the bulkhead. I can't find any links in the tank fittings or any leaks from the shower, kitchen faucets or head sink lines... All of those areas are dry.
You could temporarily block those bulkhead holes one at a time working away from the pump and use the dye test to try and see what area it is coming from.
To confirm the tank is not a culprit why not take the inlet line to the pump and feed it dye from a bucket? Doing that and the above should help locate the area of failure.
Posted: Thu May 06, 2010 1:40 pm
by vabeach1234
My F26 water tank in the V-Berth floor leaked from the top everytime I filled it or was in rough seas. After removing the wood top and seeing how the whole system worked (which I didn't like) I decided to just put in a Plastimo flexiable water tank (bag) in the original water tank/tub, plumb it and put the water tank cap/top back on. I lost some capacity but it hasn't leaked since and it was a pretty simple fix. The plastimo tanks aren't cheap but again it was pretty simple.
http://www.plastimousa.com/Water%20Tanks.pdf
Posted: Thu May 06, 2010 3:37 pm
by vabeach1234
Posted: Thu May 06, 2010 9:27 pm
by RWS
ready123 wrote:CaptMike wrote:when the water pump is on the tank seems to drain faster... The pressure switch on the water pump is broken too... Also, the forward bilge fills first then moves to the mid bilge because they are connected though a drain hole in the bulkhead. I can't find any links in the tank fittings or any leaks from the shower, kitchen faucets or head sink lines... All of those areas are dry.
You could temporarily block those bulkhead holes one at a time working away from the pump and use the dye test to try and see what area it is coming from.
To confirm the tank is not a culprit why not take the inlet line to the pump and feed it dye from a bucket? Doing that and the above should help locate the area of failure.
Mike is right.
Drain the tank first, then disconnect the line that goes to the supply pump and pu tit in a bucket with some - yellow? O.K., bad idea, BLUE? dye
leave the pump on pressurized (after you fix the sensor) and look for blue.
RWS
Water leak figured out, but have shaft packing leak too
Posted: Fri May 07, 2010 3:30 pm
by CaptMike
Fixed the fresh water leaks... Thanks for the help.
In my quest for leaks and weeps, I have found that both shaft packing areas are leaking... One has a good steady drip going that was contributing to the problem. Nothing in danger of sinking unless I had now power to the bilge pumps for a couple of weeks, but it needs to be taken care of.
Can anybody tell me if my 1991 10.8 with 454 crusader, v drives, are supposed to be "dripless". Can't tell. Also, have some leaks/wheeps around rudder housing, stern zinc bolts, still on the hunt for more. I feel like the o rings may be bad on the shafts... Can't tell.
