Question: how do you cut a rebate around a hole in
fiberglass hull? Can you use a regular router and bits?
I'm unexepctantly facing the usual problem of transducers and deep
bilge hulls. I built a fairing block, and have the mushroom
head of the tranducer pointed right down as well as pressed up against the
hull as close as it can get from the outside, but leaving barely enough threads on the inside to secure it. ( I was misadvised that it would fit just fine where I drilled the 2" hole.) I'd like to router a rebate around the
transducer hole on the
interior side of the hull, to fit the 1/2" washer and get it to a
depth of at least 1/2" -3/4" too so I can get the washer down tight. (I have a little 1/4" shank Makita router which I can just barely fit and turn about 280 degrees around in the 2" hole before it bumps against an edge of
interior joinery so that's another complication.) The thickness of the hull is 2" down to 1.5", so there's plenty thickness to dig into, plus the fairing block on the outside is pretty heavy and will be glassed in place. I'd like to leave as much material as possible of course but I can just enlarge the 2" hole to a 3" one, install the tranducer on to the back of the tranducer fairing block instead of interior of hull, knowing that the fairing block is epoxied into place and thicker than the hull itself.
Also here's how I made a
transducer fairing block in case it helpscanyone, it it like grade
school arts n crafts class
1- I used sculpting clay to shape it to sorta reduce drag maybe who knows I'm no
water engineer...
2- taped over the area around the tranducer hole on the hull exterior and slapped the clay sculpture up against hull (water makes it sticky) and further shaped it
3- waxed the area with
mold release wax but not necessary since clay will just wash out of
mold, and tape ensures nothing sticks to hull
4- a few layers of
fiberglass material over it
5- peel whole thing off hull after curing, wash out the clay, cut off sharp pokey bits and now you have a mold for a fairing block that perfectly matches the contours of your hull.
6- wax the inside of the mold well, fill with
epoxy filler, let cure. After cured,, sand exposed area flattish back of the block to remove any bumps ( easier while in mold) and pop it out of mold (might have to use chisels, and cut the mold. If there are voids in the casting, fill and sand until fair.
7- line tranducer fairing block up to tranducer hole and adhere to hull exterior. The tranducers itself will go in with 4200 but the fairing block will never be removed so it is glassed.