1973 36 GB water tank removal

[Rick U]

My name is Rick and live in the Puget Sound (Seattle). My wife and I own a 1973 36 Grand Banks (first glass). Both water tanks are leaking and need to be removed and replaced. My question is can the tanks be removed intact or need to be cut up to a smaller size. I plan to stack smaller tanks in there place. I certainly can not be the first to have this issue. Any and all comments, opinions, or first hand knowledge would be greatly appreciated.

 

[Bob Cofer]

Hi Rick,

Depending on the model of 36 you have it is possible to remove them whole. So the question is what model?

 

[Comodave]

Welcome aboard. Cutting them up isn’t too bad a lob. I would just try getting them out in one piece and if that doesn’t seem to work then cut them up. As far as the new tank, check out Ronko or Ronco. I never get the spelling right…. They make hundreds of stock tanks and will put in the fittings where you specify. They make a quality heavy wall tank.

 

[Rick U]

Thanks for the quick responses!!
The survey just says it is a 1973 GB Classic Trawler #369. Did not see a model number/name. I do have one tank loose and I don't see any chance of it coming out intact. But there may be tricks I don't know. Wondering if the tanks were installed first and then the aft superstructure. I will research the tank manufacturer, sounds good.
Any further advise is always welcome.
Rick

 

[mmullins]

Are they in the very back of the boat? We have a '78 37' Hershine that had them located under the rear deck behind the aft cabin. They measured smaller than the hatch opening but we couldn't get them angled enough to clear. So, 2 guys and a sawzall had them out in a matter of hours. We put smaller plastic tanks in and now have a lot more storage for lines and bumpers.

 

[Comodave]

What are the current tanks made out of?

 

[Pete Meisinger]

I never could wrap my head around the need to replace fresh water tanks just because they leak a little. If you have a complete tank breakdown, or a "gusher" maybe it would need replacement but pin holes or a slow leak, why bother?

pete

 

[Flatswing]

My name is Rick and live in the Puget Sound (Seattle). My wife and I own a 1973 36 Grand Banks (first glass). Both water tanks are leaking and need to be removed and replaced. My question is can the tanks be removed intact or need to be cut up to a smaller size. I plan to stack smaller tanks in there place. I certainly can not be the first to have this issue. Any and all comments, opinions, or first hand knowledge would be greatly appreciated.

I replaced my water tanks on my ‘98 GB 36 classic due to Aluminum corrosion. The 42 classic has 3 tanks so you can remove the center tank then slide the outboard tanks over to remove. Unfortunately, most GB 36 classics have 2 tanks so you will have to cut at least 1 up with grinder to remove from the lazarette.
Once that’s done make a plywood mock up of the size tanks you wish to reinstall, to make sure the new ones can be inserted. I had to drop the capacity of each by 10-15 gallons. cheapest is to use a premade Ronco (you can spec fill access & outflow spigot anywhere on their tanks). Otherwise you will need custom poly.

 

[Old Sea Dog]

Hey Rick. I will be removing mine today hopefully. I have already dismantled the wood framing for the teak grating and the port water tank. Also found a few more projects while poking around down there. Looking at replacing with Ronco Plastics tank B283. 60 gallons. Will be checking measurements today for getting those tanks in.
BTW... 1979 GB 36 classic #599.

 

[Rick U]

Many thanks to all who have provided me with their assistance, it has given me some new thoughts, but mostly confirmed how I should proceed. I am not sure what the tank material is; it looks stainless. In either event, I'm starting with new tanks. I will try to get one tank out intact once I remove the first by cutting. Great option. Will also make a trial tank frame to ensure the largest tank which will fit (measure twice). Have found at least one firm which will make custom tanks, but will determine if the Ronco group has one which would be appropriate. Would be interested in how the ongoing repairs are going, I will provide some updates as I proceed. Thanks again to all who have responded.

 

[Old Sea Dog]

My tanks are stainless.

 

[CharlieO.]

Old Sea Dog, you are running into the same project creep as I did. I am now on to the reassembly portion of the lazarette. I am not replacing my water tanks at this time, luckily they came out in one piece, just barely though, had to really squeeze them out.

I do have a post going on my project too.

Good luck and I look forward to following along.

 

[Rick U]

Need more opinions and guidance from the old Pros. The Ronco and Plastic-Mart tanks are not baffled. The existing tanks are baffled which indicates they should be. A sales rep from Plastic-Mart says they sell hundreds to the boating industry inferring baffling in not necessary. Are there any manufacturers that make baffled tanks, does anyone have first hand experience with 60-100 gallon un-baffled tanks?
Need some help before I proceed.

 

[alormaria]

I have a pair of un-baffled 75 gallon stand-up water tanks.

Perhaps because they are standing up they don't need to be baffled?

 

[Old Sea Dog]

Well, going to need to be cut up into thirds to get out. Not enough room to tilt the tank. Top hits the 90° drain fitting for the lazerette hatches. So tomorrow will use up a 4" grinding wheel and 4 or 5 saws all blades.
Good news is Defender delivered my 3.5in exhaust hose and clamps

 

[Comodave]

Need more opinions and guidance from the old Pros. The Ronco and Plastic-Mart tanks are not baffled. The existing tanks are baffled which indicates they should be. A sales rep from Plastic-Mart says they sell hundreds to the boating industry inferring baffling in not necessary. Are there any manufacturers that make baffled tanks, does anyone have first hand experience with 60-100 gallon un-baffled tanks?
Need some help before I proceed.

Roto molded tanks can’t have baffles. Our 50 gallon holding tank is not baffled. I suspect you will be fine with the heavy duty walls of the Ronco tanks.

 

[Bmarler]

Need more opinions and guidance from the old Pros. The Ronco and Plastic-Mart tanks are not baffled. The existing tanks are baffled which indicates they should be. A sales rep from Plastic-Mart says they sell hundreds to the boating industry inferring baffling in not necessary. Are there any manufacturers that make baffled tanks, does anyone have first hand experience with 60-100 gallon un-baffled tanks?
Need some help before I proceed.

Many times metal tanks are baffled to prevent drumming, or oil canning. That’s where the sides of the tank flex in and out as they’re filled or sloshed about. This can have detrimental long term effects on the weld seams as well as just be an irritating noise.
Ronco tanks have 3/8 thick walls (I think) and are far less likely to have the same problems.

 

[Rick U]

I have the port tank out (via cutting in half) and have the starboard free but have the same issue as "Old Sea Dog". The tank is smaller than the exit, but it will not tip clear of the drain section on the lazerette. Back to the grinder, snipper, and Saws All.

Thanks to those who commented on unbaffled tanks. It sounds like most replaced tanks are simply not baffled. I would still appreciate more comments from those who have replacement tanks which are not baffled. Good comments on the "drumming" and "strength" issue. Still somewhat concerned regarding the stability of half full tanks in rough weather. Any more personal experience would be great!!
I am getting closer to getting this project completed; just in time to fix something else. It is a boat.

 

[Cigatoo]

We have (3) new plastic water tanks in our GB 36. Made in Maine. I am guessing 50- 60 gallons each with no baffles. I can get you the manufacturer info if you would like.

 

[Rick U]

Cigatoo/ Carl, Yes please. Will add the manufacturer to my list of providers.

 

[Old Sea Dog]

Port tank out. Had to nibble it down to the last 1/3 piece that came out. Ended up being 2 vertical baffles and 1 horizontal in each 1/3 section.
Last picture I believe is the result of previous owners continually stepping on the quadrant. To bend or replace?
Cig/Carl.... where do you have a third water tank? Plus 1 on the make and model # of your replacement tanks.
Thanks all!

 

[Comodave]

Not a good step. Maybe take it to a machine shop and see if they can straighten it out. If not the definitely replace it.

 

[Cigatoo]

There are 3 rectangular water tanks in our Lazarette.
Made by Triple M Plastic Products in Maine
Each tank is 27" tall x 24" wide x 18" deep (Rough measurement)
According to Google that equates to 54.5 gallons per tank?

The last photo is looking down inside the fill hole of one of the tanks. They are partially baffled.

 

[Juggerknot]

There are 3 rectangular water tanks in our Lazarette.
Made by Triple M Plastic Products in Maine
Each tank is 27" tall x 24" wide x 18" deep (Rough measurement)
According to Google that equates to 54.5 gallons per tank?

The last photo is looking down inside the fill hole of one of the tanks. They are partially baffled.

Those are welded tanks you have.

 

[ASLIII]

Leaking Water Tanks

I never could wrap my head around the need to replace fresh water tanks just because they leak a little. If you have a complete tank breakdown, or a "gusher" maybe it would need replacement but pin holes or a slow leak, why bother?

pete

We have dealt with leaking water tanks for years on our 1984 Defever. There are multiple patches from the previous owner, and the tanks do leak slowly, but we are able to keep more than adequate fresh water for trips, and the slow leakage keeps the bilge clean (sort of). We have investigated opening the tanks to install smaller tanks in the opened ones, but this would involve taking up and then replacing most of the flooring. I agree with Pete- patch and tolerate. Good luck!!

 

[Turning Point]

Should you decide to go with Ronco tanks, a purchase order on a letterhead will result in a 50% discount, or at least it used to.
(Be sure to keep this a secret

 

[Cigatoo]

Those are welded tanks you have.

I’m pretty sure they are water tanks.

 

[Old Sea Dog]

Cig.... are the tanks interconnected or 3 separate tanks? Water pick up on top? I see one shut off. Interesting tanks. I have opted to keep the original starboard tank. No going through the labor intensive removal process again.

 

[ronobrien]

I removed them from my 1973 GB36. I did cut one and removed the other whole. I think they both can be removed whole but it involves removing the exhaust hose(s), removing the retaining block at the outboard end of one tank and sliding that tank all the way outboard. Then there is room to slide the other tank to the center of the lazzarette opening for removal. The other tank is then slid over and removed. after considering the associated work I elected to remove the first one by cutting. My replacement plan is for (2) 40" wide tanks which will both go in with all other equipment in place, then putting in a third tank aprox 30" wide between the two larger ones. This will be more expensive but the tanks can be serviced (removed) without any great fuss. As a bonus I figure to pick up an additional 50G (aprox) this way. Good luck.

 

[Cigatoo]

Cig.... are the tanks interconnected or 3 separate tanks? Water pick up on top? I see one shut off. Interesting tanks. I have opted to keep the original starboard tank. No going through the labor intensive removal process again.

3 separate tanks.

There is a ball valve / shut off on the top of each tank. So you can choose any single tank or all.

I usually drain the 2 outside tanks. When they are empty I use the center tank as a reserve knowing that it is time to refill. Only problem if they suck air it takes a little effort to re prime the pump.

The tubes run straight down from the top of each tank. (Can see in photo)

Very happy with them FWIW