I have a 17' aluminum boat with two downriggers mounted on the gunnels
and some chambers. I am using eight pound weights.I get a very loud hum
when trolling. Is this a common problem and can it be solved.
-On a 16' aluminum with two downriggers I get a hum when moving >1.5 mph with
the riggers set at less than 75 ft. or so. The downriggers are mounted on a
10X2" wooden board that runs accross the stern, I've always figured it's the
cable thats vibrating and not the boat too.
-I use to get the same noise in my 14' aluminum boat. In fact, the
more cable I let out, the louder the hum. I guess it's because you got
one long guitar string out in the water using your boat as the
acoustic chamber. I also see and hear the same noise from other boats.
But when I sold my 14' boat and installed the 'riggers on my 16' boat
with carpeting, the hum disappeared. The 'riggers are mounted on
storage/flotation chambers on each side of the boat. Try in find a way
to insulate your mountings.
-If your guitar string theory is valid (which I do buy it), then it'd
happen on any boat, even your 16' carpeted