When Tangleberry was new we installed a stereo system with the head unit in the main panel, two speakers in the main saloon and two in the cockpit. The radio was an Automotive type with CD player. It lasted ten years or so but died after some fool — me — left a port open when sailing, and we caught a blow. Salt water and a non-marine stereo didn’t mix well. The replacement is a marvelous Fusion system with SiriusXM satellite radio. No CD player. Truly waterproof. This week I was cleaning the boat and put some music on in the cockpit to make the work go faster. I noticed the sound was distorted, but only on the cockpit speakers. These were very expensive Babb marine units, but dating from 2002. They sounded great when new, but the weak plastic grills soon got kicked in, and I made replacements out of 3 mm aluminum which still looked good. On close inspection I could see holes in the cone surrounds which not only ruined the sound but could allow water in.
I took one out and measured the hole. Babb is long out of business, so I searched the internet for an exact replacement. No luck. However Fusion speakers received excellent reviews so I bought a pair of FR-6022 6″ speakers from Steveston Marine. They almost fitted but not quite. The original hole was 4.8″ and the old speakers had plenty of room. The new ones called for a 5″ hole and they meant it.
After considering filing, sanding, and routering to enlarge the hole I decided to use a hole saw. My general policy on tools is buy them when the need arises. In forty years of boat ownership I have acquired a large assortment of hole saws, but the largest was 4.8 inches. Coincidence?
I bought a 5″ hole saw. For a hole saw to work properly you need a small center guide hole. Lacking that I made this out of some scrap Starboard:
I used the old screw holes to put this on the inside of the hole. The hole saw, powered by a big Milwaukee cordless drill, worked smoothly and quickly.
Some cleanup and I installed the new speakers. They sound excellent. The grilles seem pretty strong, so I hope they will last.