Cool - that's good to hear. I also did a little more googling last night and found this (below) on the USCG site. In a nutshell, as long as the compartment is sealed with no non-ignition protected devices installed or isn't opened to another compartment (drainage?) that has a non-ignition protected device, then it's OK. What's interesting, though, is that I also found mention (although not on the CG site) that if the tank is plastic it would still require ventilation, whether natural or powered.
FEDERAL LAW
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:
(3) Contains a permanently installed fuel tank and an electrical component that is not ignition protected in accordance with Sec. 183.410(a).
OPEN TO THE ATMOSPHERE
Compartments that are open to the atmosphere do not require additional ventilation.
FUEL TANK COMPARTMENTS
A compartment containing a fuel tank that is permanently installed, as opposed to a portable tank or container, does not require natural ventilation unless the compartment contains an electrical component that is not ignition protected.
Ignition protection is defined in Title 33 CFR Subpart I - Electrical Systems,
183.410(a) as follows:
"(a) Each electrical component must not ignite a propane gas and air mixture that is 4.25 to 5.25 percent propane gas by volume surrounding the electrical component when it is operated at each of its manufacturer rated voltages and current loadings, unless it is isolated from gasoline fuel sources, such as engines, valves, connections, or other fittings in vent lines, fill lines, distribution lines or on fuel tanks, in accordance with paragraph (b) of this section."
Another definition is:
"The design and construction of a device such that under design operating conditions:
it will not ignite a flammable hydrocarbon mixture surrounding the device when an ignition source causes an internal explosion, or
it is incapable of releasing sufficient electrical or thermal energy to ignite a hydrocarbon mixture, or
the source of ignition is hermetically sealed."
"Ignition protected" devices are not necessarily "explosion proof "or "intrinsically safe" as those terms are defined by the National Electrical Code and Title 46 CFR Part 111, sections 105-9 and 105-11. If, however, a device does meet the definition of either "explosion proof" or "intrinsically safe", as referenced above, then it is also "ignition protected" as defined in Title 33 CFR Subpart I - Electrical Systems.
Test standards to determine ignition protection may be found in SAE J1171, External Ignition Protection of Marine Electrical Devices, and in UL 1500, Ignition Protection Test for Marine Products.
Usually fuel level senders and the associated wiring are not sources of ignition and therefore would not normally require natural ventilation.
TO COMPLY WITH THE LAW
Does the compartment contain a permanently installed fuel tank and an electricalcomponent that is not ignition protected?
If YES, then one of the following must be answered YES.
Is the compartment open to the atmosphere as defined in 183.605, or
Is natural ventilation provided? See 183.630 for requirement.
FEDERAL LAW
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:
(3) Contains a permanently installed fuel tank and an electrical component that is not ignition protected in accordance with Sec. 183.410(a).
OPEN TO THE ATMOSPHERE
Compartments that are open to the atmosphere do not require additional ventilation.
FUEL TANK COMPARTMENTS
A compartment containing a fuel tank that is permanently installed, as opposed to a portable tank or container, does not require natural ventilation unless the compartment contains an electrical component that is not ignition protected.
Ignition protection is defined in Title 33 CFR Subpart I - Electrical Systems,
183.410(a) as follows:
"(a) Each electrical component must not ignite a propane gas and air mixture that is 4.25 to 5.25 percent propane gas by volume surrounding the electrical component when it is operated at each of its manufacturer rated voltages and current loadings, unless it is isolated from gasoline fuel sources, such as engines, valves, connections, or other fittings in vent lines, fill lines, distribution lines or on fuel tanks, in accordance with paragraph (b) of this section."
Another definition is:
"The design and construction of a device such that under design operating conditions:
it will not ignite a flammable hydrocarbon mixture surrounding the device when an ignition source causes an internal explosion, or
it is incapable of releasing sufficient electrical or thermal energy to ignite a hydrocarbon mixture, or
the source of ignition is hermetically sealed."
"Ignition protected" devices are not necessarily "explosion proof "or "intrinsically safe" as those terms are defined by the National Electrical Code and Title 46 CFR Part 111, sections 105-9 and 105-11. If, however, a device does meet the definition of either "explosion proof" or "intrinsically safe", as referenced above, then it is also "ignition protected" as defined in Title 33 CFR Subpart I - Electrical Systems.
Test standards to determine ignition protection may be found in SAE J1171, External Ignition Protection of Marine Electrical Devices, and in UL 1500, Ignition Protection Test for Marine Products.
Usually fuel level senders and the associated wiring are not sources of ignition and therefore would not normally require natural ventilation.
TO COMPLY WITH THE LAW
Does the compartment contain a permanently installed fuel tank and an electricalcomponent that is not ignition protected?
If YES, then one of the following must be answered YES.
Is the compartment open to the atmosphere as defined in 183.605, or
Is natural ventilation provided? See 183.630 for requirement.
