Hole drilling advice ...

[ParaHandy]

planning to drill approx 50mm hole in hull for through hull depth transducer fitting. I intend drilling through the existing faired housing which used to hold a 'potted' transducer.

this could have unwanted consequences if it goes wrong ...

any advice eg hole saw type etc, gratefully received ....

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[tcm]

If the hole is big enough to make a start, you can enlarge the hole with a flap sanding attachement. I wd be v careful about attempt a rip through a hull with conventional hole cutter and 240v drill as the costs of a cockup aren't acceptable. Much better to mark up the hole you need and enlarge existing hole with a flap sander or dremel, imho.

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[MIKE_MCKIE]

When I did the same, the fairing came off with the old e/s transducer!! In the end it was a lot easier to glass in the hole & fit the new transducer in a plastic pipe glassed to the inside of the hull (vertical) and filled with oil. One less hole in the boat, and tranny is readily accessible in the unlikely event of a failure. Mine is the Nasa Clipper Duet & works a treat. It actually came complete with the plastic pipe, but a bit of 38mm plastic water pipe will do the job. There are some other posts today about where to put the tranny (mostly polite). I would certainly not drill a hole for one again.
Best of luck.
Mike

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[ParaHandy]

no .. there isn't a hole. the existing transducer is set back from the surface and transmits through a relatively clear resin window 4-5mm thick. having said that the diameter of the transducer is approx 30mm so opening it out might indeed be safer ...

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[Chris_Robb]

Can you not remove the existing tube and reseat a larger piece of plastic plumbing pipe in the same place to fit the new transducer?. I have - or rather had - on Corsair 2 tranducers - one set internally in a tube for the old wizzy job and a modern rathion job - mounted through the hull. The problem with this one was that there was no where to mount it vertically ans the hull in the bows section is a about 45 deg - but it does work well - execpt in deep water it gives up at around 70 to 100 mteres.

If you do drill through the hull, I used a standard hole saw - but because the hull was so thick I had to drill from both sides, which is not a problem as the central drill hole locates it very accurately. Once you have cut the hole make sure you properly seal the exposed laminates with epoxy, rather than just relying on secoflex.

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[tcm]

If hole driling, i wd want a really decent drill and a new hole saw attachement - need the speed control cos tip speeds are high. 110V would give more oomph of course, otherwise a decent bosh er Bosch. I might even go the whole (haha) hog and get some goggles, and anything gloopy like some polish to dribble about and keep the nasty grp dust to a minimum.

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[Benbow]

I would strongly advise you use a good quality hole-cutter of exactly the size required. Not those horrible nesting cheapo things. I certainly would not attempt to sand-out a smaller hole, you want the best fit you can get. I have done this many ttimes with good results.

However, I agree that you usually don't need a hole at all for a depth transducer, you get some loss of maximum depth, but its shallow water that is more important.

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