Feeding the Westerbeast with a Polyethylene Holding Tank?

[GrowleyMonster]

My installed fuel tank for my 4-107 is woefully small. Surveyor says 14 gallons. Outside measurements indicate closer to 18 gallons. It looks to my eye to be a bit over 10 gallons. Anyway it isn't very big. There is room for a tank over twice as big, simple drop-in installation over the keel aft of the mast.

So, I was at Worst Marine yesterday and they had a nice looking tank set up as a holding tank or FW tank, made by Todd, rigid plastic. Ordered by a customer who decided he didn't want it, so it is slightly discounted to get it off the shelf. I may get it anyway since I need to isntall a head so Mrs. Monster doesn't have to poop in a bucket when we go for a sail out on Lake Pontchartrain or just spend the night aboard at the dock. But I really need a cheap option for more juice for the Westerbeast. I can't afford any other options I have explored, even welding my own. I could make a steel tank but after a lifetime on steel ships I really don't like messing with stuff that rusts now that I am retired. I don't have any experience welding aluminum though I have a nice spool gun, but I don't have shielding gas or a bottle for it and aluminum isn't cheap. The poly tank is pretty cheap and would about 2/3 fill the available space, and holds 35 gallons.

Knowledgeable people... your thoughts?

[Compass790]

You would want to be sure the plastic was fuel resistant.
If its the same material as plastic fuel cans I'd go for it. I'd imagine its fairly chemical resistant if its good for sewage but thats a guess.

Wise move not considering a black steel tank IMO. Other option is to make out of plywood & fibreglass. You can do that pretty cheap.
Dont know anything about insurance regs in the USA if thats a consideration.


WHOOPS quick google search showed this:
Hydrocarbon fuels such as diesel are known to permeate into and pass through polyethylene over time. As diesel fuel permeates into polyethylene the material becomes softer and more flexible. ... Chemical compatibility was tested by immersing samples of Alkatuff LL711UV in diesel fuel for a period of 4 weeks.

[GrowleyMonster]

Originally Posted by Compass790

You would want to be sure the plastic was fuel resistant.
If its the same material as plastic fuel cans I'd go for it. I'd imagine its fairly chemical resistant if its good for sewage but thats a guess.

Wise move not considering a black steel tank IMO. Other option is to make out of plywood & fibreglass. You can do that pretty cheap.
Dont know anything about insurance regs in the USA if thats a consideration.


WHOOPS quick google search showed this:
Hydrocarbon fuels such as diesel are known to permeate into and pass through polyethylene over time. As diesel fuel permeates into polyethylene the material becomes softer and more flexible. ... Chemical compatibility was tested by immersing samples of Alkatuff LL711UV in diesel fuel for a period of 4 weeks.

Ah. Well then. That pretty much makes an unbeliever out of me. I won't be using a poly tank for diesel fuel. Thanks for posting. Glad I asked, now.

[JPA Cate]

Growly, Jim had an aluminum fuel tank made for our previous boat. It was a 45 gal. tank, and whatever it cost back then, Jim never complained about it. So, maybe it would be an option for you, even now. It was installed where we could see the top of it, and Jim had ordered it with a fuel gauge, which required sealing up with MarineTex underway. If you do it and order a fuel gauge, you might want to figure out a way to pressure test it prior to installation.

Since it's a steel boat, maybe s/s tank? We had s/s water tanks in the boat above, and the big deal was to space them off the hull, but they lasted well, kept the water where we wanted it. Pretty trouble-free. If you're already someone who welds, the s/s should be doable, with no dissimilar metals issues.

Ann

[KadeyKrogen38]

Suggest you install a composting head. Then use the space you identified for black water tank for fuel. These heads are great no smell no plumbing.

[mitiempo]

Moeller Marine makes approved fuel tanks - they have many sizes to choose from.

Permanent Fuel Tanks | Moeller Marine

[kryg]

I agree that you need to insure the tanks your considering are fit for purpose. I don't like plastic on a boat except for one use Tankage - I have Plastimo 100 litre plastic tanks now 35 years both for 2 x water and 2 x for diesel fuel! They can serve the boat for another 35 years!

Originally Posted by GrowleyMonster

My installed fuel tank for my 4-107 is woefully small. Surveyor says 14 gallons. Outside measurements indicate closer to 18 gallons. It looks to my eye to be a bit over 10 gallons. Anyway it isn't very big. There is room for a tank over twice as big, simple drop-in installation over the keel aft of the mast.

So, I was at Worst Marine yesterday and they had a nice looking tank set up as a holding tank or FW tank, made by Todd, rigid plastic. Ordered by a customer who decided he didn't want it, so it is slightly discounted to get it off the shelf. I may get it anyway since I need to isntall a head so Mrs. Monster doesn't have to poop in a bucket when we go for a sail out on Lake Pontchartrain or just spend the night aboard at the dock. But I really need a cheap option for more juice for the Westerbeast. I can't afford any other options I have explored, even welding my own. I could make a steel tank but after a lifetime on steel ships I really don't like messing with stuff that rusts now that I am retired. I don't have any experience welding aluminum though I have a nice spool gun, but I don't have shielding gas or a bottle for it and aluminum isn't cheap. The poly tank is pretty cheap and would about 2/3 fill the available space, and holds 35 gallons.

Knowledgeable people... your thoughts?

[GrowleyMonster]

Originally Posted by KadeyKrogen38

Suggest you install a composting head. Then use the space you identified for black water tank for fuel. These heads are great no smell no plumbing.

Nah can't do that. Well I could, but the head is a long way from the centerline of the boat. And yeah I have thought about a composting head but our marina doesn't approve composting heads. I can't get liveaboard privileges without a proper holding tank. However I have decided I won't use that big 35 gallon tank for the head, either. There is a very small tank I found in the bilge that was apparently meant to be installed as the holding tank, and I might use that but I am thinking better to go with about a 10gal tank so Mrs Growley doesn't run out of tank space. The space identified for a new fuel tank, where the old one already is, is right on the centerline, aft of the single mast.

Boat isn't steel. This is a fiberglass version. No way in hell, after a lifetime of maintaining steel ships, am I going to bust rust for fun in my retirement. Most of the Bruce Roberts designs could be built in either fiberglass or steel. And yeah a SS tank would be good but just like aluminum, I need to set myself up with shielding gas to weld SS properly. DIY SS or aluminum DIY is not totally out of the question because I can also make a little coin building boarding steps, swim ladders, and other custom stuff, and I really wouldn't mind having a nice gangway for Brute Force. But Mrs Monster wants to give me a custom fabricated tank for my birthday and there are some good yards on the West Bank for that kind of stuff.

Plastimo and Moeller are possibles. I haven't shopped their sites yet.

I did get my fuel gauge working, sort of. I need a new gauge. The tank is verified full to the top, and the resistance is 35Ω, and I got power to the gauge cabinet and to the fuel gauge. The gauge, when connected, reads at exactly 100% full. The problem is, then it gets stuck there. I can remove power and I have to bang the gauge to get it to go back down. I just got a 100w 0-500Ω pot and sometime this week I will hook it up and see if it will read properly all through the normal range, and change as I change the resistance. But I think something is wrong with the gauge. Voltmeter is toast. I have to replace that. Ammeter is not hooked up and I don't know what size shunt it requires or if it is made to work directly without a shunt. Tach I don't think was ever hooked up, got to do some research on it. Not sure if it is usable with the diesel. I suspect it is the type that works off the ignition system of a gasoline engine. Not sure if I can make it read accurately with input from the alternator or not. Still haven't messed with water temp gauge yet. Can't find the sending unit on the Westerbeast. More research needed.

Today was productive, though. Got some circuits traced, got the FW pump working completely by accident and by surprise. Installed a push button start switch, so no more poking a loose wire to start the Westerbeast. Some barstid apparently collided with me and wiped out my sidelights. I hope his gelcoat got a good taste of my big mean ugly anchor in the process. My ad hoc bilge pump isn't working anymore. There is another pump somewhere keeping the boat pumped out and the float switch on my cheapie pump never closes.

Two hoses that have been puzzling me now have me thinking that the boat was switched to raw water cooling. I got to investigate that cause I don't want raw water cooling. Lake Pontchartrain is not really a lake. The water is brackish, often almost all salt. Almost really a small inland sea. I don't care to run seawater through this elderly engine especially now that i seem to have it running so nicely. With the cabin sole all closed up it purrs like a kitten and doesn't smoke anymore, even on start. Anyway the clincher is I can close the seacock that goes to the water pump and she still splurts water out the wet exhaust just the same as with it open.

I am just going to have to show this boat who is boss, I guess. I am dealing with a full scale insurgency of wierd installations and hookups and mystery fuse pannels and hidden switches and wires that go nowhere and mysteries aplenty. Tomorrow I go tank shopping.

Maybe I just go fishing tomorrow instead.

ANyway thanks a lot for all the great replies, everyone!