Yes. I bought a boat that had a hull-mounted type transducer mounted internally. It worked OK, but suffered odd losses of signal occasionally. Then something heavy in the locker knocked the tube and all the oil ran out, so I decided to mount it through the hull. Performance of the unit increased significantly. This was a GRP hull, no experience with wood.
Most fish finders have a transom mounted option but depends on stern as it does not read if it comes out of the water! but might work on some motor sailers. Most makes also do a longer bronze transducer designed for wooden hulls. I managed to fit a Silva standard sensor by screwing and bonding the mounting tube through a fairing block on the outside and abandoning the internal nut. This seems to have worked ok as the depth of the hole it is mounted in is over 4" so there is lots of bonding surfice.
Yes, it's very easy to do with the right tool. It's so much easier nowadays, superb tools available at most DIY places at very reasonable prices. Drill part way from one side with the hole cutter, then finish from the other side.
A slightly bigger challenge was with the current boat, enlarging the transducer hole size from the old 1 inch to new 1.5 inch. Problem is there's nothing for the pilot drill to bite into. I made up a roughly round bit of wood and knocked that into the hole first, job then very straightforward.
Take your time,measure twice and cut once.have put a couple of log spinners in .Only problem was with a resited head Through hull .the body didnt leak only the tapered plug.Couldnt stop it.so over the side with a wooden plug and hammer,
Bucket and chuck it for the next two weeks.SHMBO was not very impressed.
Make sure the sealant is suitable for underwater use though
There are some posts further down this thread suggesting an in hull fitting, but this is only possible for glass fibre boats and will not work for wood. The only option I know about, apart from a transom mounted speed boat type, would be a Speedtech Depthmate SM-5.
This is the 2002 version of a lead line, that is to say you lean over the side and dip it in the water to take the reading. Looks like a flashlight. Reads in feet or metres, holds the reading for 10 seconds, and updates each time the button is pressed.
UK price is £129 including vat, I'd sell to you on discount. Please e-mail me if you'd like to discuss it.
If you use a Nasa target log you can bond it straight onto the wooden hull with two pack epoxy by containing the transducer
within a purpose made mould thats epoxied to the hull first. this can be made from waste pipe cut to the contour of the hull.
A hole through the hull is your best bet, but you must make a ‘pod’ or ‘blister’ to protect and surround that part of the transducer that protrudes on the outside of the hull, so the face of the transducer is flush with the bottom of the pod.
With a wooden hull and wooden pod, you should have no trouble bonding them together (glue and screw).
Push the transducer up through the hull onto a bed of sicaflex (spelling?). Don’t be tempted to use any less reputable sealant.
No, not a lot. I have a fairly long history of boat modification and repair. Transducers have a flange at the outboard end and this doesn't mate up to the rounded shape of the hull. File off a flat at the two high points (low points?) on the hull, until the flange sits snugly all around. At this stage the transducer will be approaching water-tightness without any sealant at all, plus of course the transducer can't come through the hole.
From memory I used Boatlife polysulphide sealant, but I can't be certain. Over the years I have used a wide variety of these products, mostly with success. The most recent transducer has been there for several years now with no problems.