Marine Fuel Tanks


The design and manufacturing of marine spec aluminum tanks have always been at the core of Welding World's businesses but now we are engaged in pushing out from the circle of OEM manufacturers we already cater for and offering our manufacturing capacity at the consumer arena. In this page, you will find all of the details about the aluminum tanks we build.


All of Welding World's EPA/CARB compliant marine tanks come with top of the line headspace and vapor management systems installed in the form of BluSkies® ullage valves specially engineered and design validated for us. In a process that doesn’t cut corners anywhere Welding World’s design team engages the engineering consultants at BluSkies® to comprehensively stake that all design touch points to ensure absolute compliance with all federal safety and trade standards. That is a process that is repeated for each and every new tank design we build. No compromises, no exceptions.

 About Our Ullage Valves

Ullage valves perform all required processes for an EPA/CARB compliant marine fuel system. During refueling, the ullage Valve activates the automatic fuel nozzle shut off when fuel levels reach 95% of the tank’s capacity. They maintain the expansion space when refueling is completed to allow fuel vapors to be retained in the tank during temperature and pressure changes.

Our ullage valves provide 3 key functions for an EPA compliant marine fuel system:


  • They drive fuel up the fill hose to activate the automatic fuel nozzle shut off during refueling.



    • They allow for an exact expansion space within installed marine fuel tanks, permitting fuel expansion during daytime temperature rises, also protecting sensitive system components from contamination.



    • They provide adequate venting for vessels to meet ABYC H-24 standards.

    Our ullage valves eliminate the propensity for “spit-back”, tank “well-back” and “fuel geyser effect” during the refueling process. Our ullage valves have a simple, zero maintenance design and are produced with fuel-resistant plastics and marine grade aluminum.




    If you aspire to be the best you have to look hard at whose parts you use in your systems. Our 20+ years of experience fabricating and integrating fuel tank systems has proven to us time and again that the best in the business of tank level management is no other than KUS (ex WEMA USA®). Simply put, KUS is as stringent with quality requirements, obsessive with detail and strict with product testing and validation as we are.


    About Our Fuel Level Senders

    Fuel or water level measurements are done by a series of hermetically sealed reed switches positioned inside the main shaft of the sensor. An oil-resistant nitrile-butadiene rubber (NBR) float with built-in magnets triggers the reed switch relays, generating a potential-free Reed Switch resistance with an ohm value that increases or decreases according to the fluid level.

    The main advantage of a reed switch type level sender over a thick-film swing arm type level senders is the reed switch’s considerably increased durability and reliability because of the drastic reduction in moving parts.

    Switches used in the reed switch level senders are able to perform over 50 million actuation cycles, more than 5 times that of thick-film resistors. Additionally, in reed switch level senders, the float is the only moving part of the sensor, thereby minimizing potential mechanical failures due to corrosion or foreign object contamination.

    Our NBR floats are specifically designed to withstand long term exposure to heat, oil, chemicals, and water. The standard level measurement resolutions on our level senders are approximately 0.5” (13mm).

    However, if your level measurement application requires finer resolution, customized senders with resolutions as low as 0.18” (4.5mm) are available upon special request.

    All of our sensors are fully insulated to protect against the possibility of sparks and voltage inside the tank.





    At Welding World, Inc. we know how to build an excellent, decades lasting aluminum tank. Our master welders have individually more than 20 years of specific experience and not one of the tanks they’ve built has been returned by a client with a leak. Two decades and thousands of tanks, of every shape and capacity, zero issues. But if that's not statement enough of the uncompromised quality of our products let’s get to the nitty-gritty:

      • Cold-formed Alcoa 5052 H32 Series aluminum, internally Q. C.’ed to zero scratches or other surface contaminants.

      • Hand welded GTAW (TIG) welded to meet or exceed ASME / ASW D3.7:2004 standards. Every bead of weld laid by the expert hand and under the eagle eye of our master welders. Again, zero compromises.

      • All of our tanks are built to exacting, 100% CAD designs that prevent all common tank issues, and especially those that plague the decisively inferior plastic class of tanks, like the free surface effect. Welding World, Inc’s Aluminum larger volume tanks include multiple baffles (for longitudinal and/or lateral movement) in their holding space, at precisely calculated placing, to mitigate free surface effect and neutralize slosh dynamics. Aluminum tanks considerably outlast plastic ones, specially in boats placed under the sun and stored in high temperature climates, as heat evaporates their volatile plasticizer compounds, added to the day/night contraction and expansion cycles, detrimentally affecting most plastic tank's ability to remain gas tight as they quickly degrade under those extreme conditions. 

      • Stringent Quality Control ensures a trouble-free operation on the long span of our tank’s service decades. Qualified personnel, with comparable experience to our welder’s, perform a battery of hydro-pressure tests designed no to meet, but to exceed the current ABYC H-24 7/22 industry standard for gasoline tanks and H-33 7/21 for our diesel tank offerings. No Welding World tank is ever crated nor shipped without that testing performed and carefully documented.

    • The best surface treatment money can buy included standard, at no extra cost, with all of our tanks: Sherwin Williams® TarGard® Epoxy paint, applied to a high mil coverage, ensure an external tank’s surface free of accidental corrosion by metallic or continued water contact. Plain aluminum (no paint) finish also available upon request.