Welded plastic vs aluminum fuel tanks

[Ttownthomas]

I recently stumbled across some companies that make custom "welded" plastic fuel tanks. I assumed only aluminum tanks were customizable for reasonable money. I think I can get about 110 or so gallons (or maybe as much as 130 if I relocate my batteries) with a custom tank in my B25. Does anyone have experience with this newer plastic tank technology?

http://www.moellermarine.com/custom-con ... uel-tanks/

https://www.tek-tanks.com/custom-tanks/

http://triplemplastics.us/our-process/

[David Davidson]

A couple of years ago during a total refit I replaced the original fibreglass fuel tank with a shorter but higher welded plastic tank for diesel from Tek Tanks.
You send them dimensions (be as accurate as you can with angles), where you want pick-ups & returns, what size/type etc.
Mine arrived exactly as I ordered, very well built. Approx 750 litres capacity. Not too expensive and a good company to deal with.
My advice is order bronze tubing for pick-ups, not plastic.

I’ve had no problems so far.

[Ttownthomas]

Did you compare prices between aluminum and plastic tanks?

[Tony Meola]

As long as they can put baffles in the tank, you should be ok with Plastic. Aluminum if you prep the outside correctly should last you quite a while.

Not sure where you are located but Tek Tanks is in England, so shipping costs to the US would probably rule them out.

[Ttownthomas]

I figured they were over seas when he said 750 litres. Lol.

[David Davidson]

Hi,
Cost was about 40% less for plastic.
Baffles - 3 lateral, one longitudinal in mine
Overseas - yes UK! but during my rebuild almost everything came from the US (except the tank!). Shipping costs are just part of the cost from wherever you buy from. They were not so high. There will be plastic welding companies in the US, I’m sure, but I can only recommend Tek Tanks as that’s who I used.

[David Davidson]

750 litres
198 US gallons
165 imp gallons

[CamB25]

I have a 129 gallon, single aluminum tank. I extended the tank forward rather than into the battery area. In hindsight, I should have extended it aft to get more weight back there. I have the detailed design from Florida Marine Tanks if you would like to review. FMT is actually near you...in Henderson, NC.

Cam

[Ttownthomas]

Funny, with those heavy inline 6's in my boat I'm trying to move weight forward. I'd love to see your drawings. Still have my email address?

[CamB25]

I should, but I don't see it. Please PM your e-mail address.

It's seems counter intuitive, but weight aft is better. The boat rides on the stern portion of the hull, bow high and proud in the water. I am learning this through experience with my prop. My prop has so much stern lift that when the boat runs above cruise speed the bow starts to move down into the water. The handling gets pretty squirrely.

I need to find some lead bricks to add ballast in the stern. I'm about 3-400 lbs light back there.

Scot had a great quote from Wayne Willard (Hunt Yachts). It think goes, "It's a deep V, pile weight aft."

[David Davidson]

Cam’s right.
I created a fresh water tank between the stringers under the cabin sole which holds about 200 litres (53 US gals, 44 imp gals). When it’s full or even near full I can definitely feel it when under way. It flattens the ride and doesn’t feel good.
I nearly always keep the water tank less than half full now (or half empty depending on your personality!!).
Keep weight aft when running.

As a note, it is useful when leaving the boat for a period to fill the f/w tank to full and keep the fuel tank low of fuel. I can get the exhaust outlets well out of the water and make sure waterline is on the antifouling.