I believe the gasket would blow out long before
pressure inside a tank reached the point that a tank
could explode.
Tubs.Tubs makes a good point indeed, seems like the gasket would blow out first before the tank could ever rupture. Like others have pointed out, outboards are only capable of making a certain amount of crankcase pressure, which is relatively low. Today’s volatile fuels combined with hot weather are probably more of a danger than excess crankcase pressure. Like others have also pointed out, look at any of today’s plastic tanks that get bloated on a hot day, seems like the plastic would give way long before the sturdy two line pressure tanks of the 50s.
All fuel systems have to be properly maintained, and vented properly to avoid fires/explosions. My guess is that many fires/explosions were blamed on the pressure tanks, when maintenance, venting, and improper fueling were actually to blame.
George: I hope you get the information/specs you need to dispute this long standing myth about pressure tanks “exploding”, wish I could help.
Amen. My, how many tanks have I seen that have the bottom rim rusted away from sitting in the mud, blood, salt water and beer in the bilge. It’s easy to imagine how the bottom could blow off. In reality though, it probably starts leaking in the most rusted spot before it blows up. You still get a boat full of gas though.