Internal Fuel Tank

[skip1930]

I like the ability to pull the plastic tank out of it's cubby hole on my CP-19 to wash and de-crud underneath it. And wash the tank too. The fuel line and squeeze bulb is long enough to set the fuel tank on the settee without unplugging the fuel line to the outboard.

The tank sits on two perpendicular [port to starboard] 1/4 inch x 1 inch x full width UHMW strips glued atop those factory molded ridges designed to hold the tank up off the deck so water can run into the scuppers. I did not want to deface the gel coat layer of those ridges by allowing the plastic tank to vibrate the hard gel coat off those ridges. This would be exacerbated if the tank was metal.

During winter storage the tank comes out and any left over gas/oil mixture of 50 to 1 is syphoned into my Ford Expedition. [Imagine, some drivers actually dump a little Marvel Mystery Oil [MMO] in the fuel tank to lube the upper end and valve guides. Being of Jewish decent every shekel counts.]

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[breeze]

Bob, the total cost was about $5,500 all purchased from Hutchins you could save some money if you sourced the parts your self.
I picked up the parts from the factory, they are only 3 hr. from me.
It is not a hard project to do if you have basic glassing skills and a hand drill.
I didn't use there engine mounts, I built up the stringers and made my mounts from steel.
There's not a lot of pictures but I will post what I have.
Always happy to pass along any help.
David

[breeze]

There is no need to install a blower for a below deck gas tank that is vented and filed outside.
I do agree that a Natural Ventilation System is a good idea for all boats
The tank must be an approved tank for below deck.

This is from the USCG 2003 BOATBUILDER'S HANDBOOK | PART 1

Sec. 183.610—Powered ventilation system
(a) Each compartment in a boat that has a permanently installed gasoline engine with a cranking motor must:
(1) Be open to the atmosphere, or
(2) Be ventilated by an exhaust blower system.

Sec. 183.620—Natural ventilation system
(a) Except for compartments open to the atmosphere, a natural ventilation system that meets the requirements of Sec. 183.630 must be provided for each compartment in a boat that:
(1) Contains a permanently installed gasoline engine;
(2) Has openings between it and a compartment that requires ventilation, where the aggregate area of those openings exceeds 2 percent of the area between the compartments, except as provided in paragraph (c) of this section;
(3) Contains a permanently installed fuel tank and an electrical component that is not ignition protected in accordance with Sec. 183.410(a);
(4) Contains a fuel tank that vents into that compartment; or
(5) Contains a non-metallic fuel tank:

[brackish]

There is no need to install a blower for a below deck gas tank that is vented and filed outside.
I do agree that a Natural Ventilation System is a good idea for all boats
The tank must be an approved tank for below deck.

This is from the USCG 2003 BOATBUILDER'S HANDBOOK | PART 1

Sec. 183.610—Powered ventilation system
(a) Each compartment in a boat that has a permanently installed gasoline engine with a cranking motor must:
(1) Be open to the atmosphere, or
(2) Be ventilated by an exhaust blower system.

Sec. 183.620—Natural ventilation system
(a) Except for compartments open to the atmosphere, a natural ventilation system that meets the requirements of Sec. 183.630 must be provided for each compartment in a boat that:
(1) Contains a permanently installed gasoline engine;
(2) Has openings between it and a compartment that requires ventilation, where the aggregate area of those openings exceeds 2 percent of the area between the compartments, except as provided in paragraph (c) of this section;
(3) Contains a permanently installed fuel tank and an electrical component that is not ignition protected in accordance with Sec. 183.410(a);
(4) Contains a fuel tank that vents into that compartment; or
(5) Contains a non-metallic fuel tank:

So the bilge which is where the gasoline from a tank installed such as yours will leak to has a natural venting system? The problem is not to protect from the normal operation of the fill or vent it is to protect from an inadvertent leak and the resulting vapors.  That is how the explosions take place, normally from the spark created from the starter on the motor but from any ignition source.  My electrical panel with spark producing devices is just above the bilge and it is also has a trapped compartment from the bridge deck.  It cannot be naturally ventilated and neither can yours unless you punch a hole in the bridge deck.

Not sure what point you are trying to make but I hope it is not to convince folks that it is safe to install a below decks GASOLINE tank that can leak and cause vapors to form in a trapped compartment without a blower system.

[HeaveToo]

I have thought about this a lot.  I then remembered that the Atomic 4 was nicknamed the atomic bomb.  This was for a reason.

Diesel is safer in boats, gas is better kept in ventilated areas.

It seems that it would be easier to carry Jerry Jugs.

[Salty19]

I would definitely shy away from a gasoline tank mounted inside the boat for the reasons mentioned.

If I was looking at a CP23, and saw an inboard gas tank with three holes drilled (one for fill, one one vent, and one line to the motor)...I would walk away right there--vent fan or not.  I would be thinking "What else has this owner done that is unsafe?"  Not to mention needing to fix three holes and lord knows what else in terms of brackets.

I'm thinking either get a large 6 gal tank or tie a plastic gas can to the stern rail on days you need a lot of range (presumably for crusing for a few days) or both.
Easy, quick, cheap, removable. 

[Bob23]

KISS! Don't reinvent the wheel. Salty, once again, is right on! The 23's are simple boats so why complicate it? Just my opinion. It would seem that installing a below decks gas tanks is altering the boat contrary to the designers and builders intention.
Bob23