I would not call it intermittent, it lasted for just 8 miles then blew again, then 100 yards, then 5 yards.
8 miles, 8 yards...doesn't matter
If it isn't blowing the second it's replaced, then it's intermittent.
Not often I agree with KW

But in this case, I do. If the fuse does not blow the insdtant you replace it, the fault is no longer there, and no matter how hard you look for it, it has gone.
If the fuse blows a short while afterwards, then in is intermittant, and only when it is in a "Blowing Constantly" state will you be able to measure and diagnose any circuits.
Sorry RustyM95, you probably are not going to see big blue sparks under the seat, the problem is probably more subtle than that.
Only advise I can give is to wiggle every wire on the circuit, operate everything and make a note of exactly what you are doing and what is being operated in a vain attempt to try to recreate the fault.
Once you can recreate the fault, either by the above, or with the ideas from others, then I`m sure that many here can then offer some helpfull assistance.
I must admit, that my initial thoughts would also be to unplug the power sounder first
:-/