DaveH6
Aluminum gas tank
Today (Nov 17, 2014) I visited Atlantic Coastal Welding Inc in Bayville, NJ to pick up this fuel tank that I had fabricated to my Bluejacket's dimensions. This company also uses the name "SpeedyTanks". An excellent company to do business with. One day after submitting my request for a quote, I had one. A day after the quote, I received a call from a company representative to ensure I considered recent EPA boat regulations concerning charcoal canisters on gas tank vent lines as well as vent valves to preclude gasoline escape from overfilling.
Reading the EPA regs section 1045.630, I found a personal exception for a home builder that grants relief from complying with the new rules. I will produce these regs if a Coast Guard boarding party asks why my boat has no sticker specifying compliance with the EPA rules.
The tank was ready, as promised, five days after I specified the locations of the tank fittings.
Why an aluminum tank versus plastic?
1. No smell from petroleum molecules permeating through a plastic tank's walls. Recent plastic tank manufacturer compliance with CARB permeability requirements may have reduced or eliminated this odor issue. A plastic tank will swell when fuel is first introduced in it thus the tank compartment must allow this swelling.
2. No Coast Guard requirement for forced air ventilation which is usually required for a plastic gas tank compartment. Want your brain to hurt? Try to figure out whether recent reductions in plastic tank wall permeability has made the Coast Guard ventilation regulations non applicable for a given tank compartment volume.
3. The tank bottom is designed to match my Bluejacket's dead rise and the tank width takes maximum advantage of the tank compartment's dimensions. Consequently, for a given length, maximum capacity is obtained. My tank is 34" long and holds 36 gallons. With the available space in my cockpit sole, the tank could have been over 50" long with a capacity in excess of 50 gallons. Had I specified that the tank sides varied in height to match the slope of the longitudinal bulkheads that form the tank compartment sides, the gas capacity would have been greater.
4. It was my decision where to locate tank fittings. The welded on 1 1/2" filler collar is 90 degrees to the tank's top surface. The fuel filler hose will come straight up thus I can use a dip stick in the tank. I have found boat analog fuel senders/gauges to be near useless. A fuel sender featuring a magnetic doughnut that slides vertically on a rod is reported to be an improvement over the lever with a float on its end. I'll give it a try. Pumping out gunk from the tank bottom will be easier with my filler arrangement. The fittings on my tank are located at the tank's aft end which will extend aft of the transom knees thus reducing the size of the splash well.
The pictured red disk is a temporary cap over the hole for the sender. The tank vent is located on the tank's starboard side which is the side of the boat where a portable gas tank may be located under the transom cockpit seat. I will keep the gas fume vent issue in mind when pondering where to hang a barbecue. The tank provider included an aluminum nipple to be screwed into the fuel pickup fitting on the tank thus no electroysis. They told me to use Permatex aviation sealant on this fitting.
5. The aluminum tank has a baffle to reduce fuel sloshing. This might help keep the sender float from spastic behavior. On a much larger tank there could be an issue of sloshing fuel upsetting a boat's balance if the tank is un-baffled.
The major advantage of a plastic tank is zero concerns about corrosion. I didn't price a plastic tank thus I know not what the cost differential is between plastic and aluminum tanks.
The black strips in the picture are 1/4" thick neoprene which will be glued to the tank bottom at the points where the tank rests on supports in the bilge.
The tank weighs 40 lbs.
Aluminum gas tank
Today (Nov 17, 2014) I visited Atlantic Coastal Welding Inc in Bayville, NJ to pick up this fuel tank that I had fabricated to my Bluejacket's dimensions. This company also uses the name "SpeedyTanks". An excellent company to do business with. One day after submitting my request for a quote, I had one. A day after the quote, I received a call from a company representative to ensure I considered recent EPA boat regulations concerning charcoal canisters on gas tank vent lines as well as vent valves to preclude gasoline escape from overfilling.
Reading the EPA regs section 1045.630, I found a personal exception for a home builder that grants relief from complying with the new rules. I will produce these regs if a Coast Guard boarding party asks why my boat has no sticker specifying compliance with the EPA rules.
The tank was ready, as promised, five days after I specified the locations of the tank fittings.
Why an aluminum tank versus plastic?
1. No smell from petroleum molecules permeating through a plastic tank's walls. Recent plastic tank manufacturer compliance with CARB permeability requirements may have reduced or eliminated this odor issue. A plastic tank will swell when fuel is first introduced in it thus the tank compartment must allow this swelling.
2. No Coast Guard requirement for forced air ventilation which is usually required for a plastic gas tank compartment. Want your brain to hurt? Try to figure out whether recent reductions in plastic tank wall permeability has made the Coast Guard ventilation regulations non applicable for a given tank compartment volume.
3. The tank bottom is designed to match my Bluejacket's dead rise and the tank width takes maximum advantage of the tank compartment's dimensions. Consequently, for a given length, maximum capacity is obtained. My tank is 34" long and holds 36 gallons. With the available space in my cockpit sole, the tank could have been over 50" long with a capacity in excess of 50 gallons. Had I specified that the tank sides varied in height to match the slope of the longitudinal bulkheads that form the tank compartment sides, the gas capacity would have been greater.
4. It was my decision where to locate tank fittings. The welded on 1 1/2" filler collar is 90 degrees to the tank's top surface. The fuel filler hose will come straight up thus I can use a dip stick in the tank. I have found boat analog fuel senders/gauges to be near useless. A fuel sender featuring a magnetic doughnut that slides vertically on a rod is reported to be an improvement over the lever with a float on its end. I'll give it a try. Pumping out gunk from the tank bottom will be easier with my filler arrangement. The fittings on my tank are located at the tank's aft end which will extend aft of the transom knees thus reducing the size of the splash well.
The pictured red disk is a temporary cap over the hole for the sender. The tank vent is located on the tank's starboard side which is the side of the boat where a portable gas tank may be located under the transom cockpit seat. I will keep the gas fume vent issue in mind when pondering where to hang a barbecue. The tank provider included an aluminum nipple to be screwed into the fuel pickup fitting on the tank thus no electroysis. They told me to use Permatex aviation sealant on this fitting.
5. The aluminum tank has a baffle to reduce fuel sloshing. This might help keep the sender float from spastic behavior. On a much larger tank there could be an issue of sloshing fuel upsetting a boat's balance if the tank is un-baffled.
The major advantage of a plastic tank is zero concerns about corrosion. I didn't price a plastic tank thus I know not what the cost differential is between plastic and aluminum tanks.
The black strips in the picture are 1/4" thick neoprene which will be glued to the tank bottom at the points where the tank rests on supports in the bilge.
The tank weighs 40 lbs.