drilling holes in fiberglass boat

[teabag]

I am going to be installing my transducer, speed wheel and outboard motor bracket to my transum. I am just wondering if there is a special silicone to use or if any outdoor /UV will do.

I figure its marking hole
drill hole
Jam it full of silicone
Then screw it in
Pray to the gods.

HOW would I be graded.

Thanks and gl this season.
Jay

[Wallyboss]

Actually your transducer you can glue to the bottom of the boat cause it will send thru the fiberglass.

[Andy_L]

hey there Jay...I moved your topic to this forum where some of the guys that specialize in boat repairs etc go read....hope you get the answer you need

cheers

Andy

[toobinator]

Jay: I use marine silicone to seal the holes, as well as putting around the head of the screw after it is tightened in. Before you drill though, put a bit of duct tape over the area you will be drilling. This prevents the fiberglass from chipping when you drill. Just peel it off after the holes are in.

Ed

[teabag]

thanks for the suggestion. I will check the chandlery tomorrow for this silicone. Damn, my boat restoration almost ready for the water.
LOL
well sand and paint next year.
good luck to all
I'll be the ugly 60;s green boat on Muskrat.
Jay

[toobinator]

Jay: Any hardware store should have this silicone. I get it at the local Home Hardware.

Ed

[mikemicropterus]

I don't diagrre with TOOB masking tape BUT YOU NEED TO CHAMFER the holes with a bigger drill or the fibreblass will crack and cause crazing and that will allow water to enter the transom....not good

I have put on hundreds of transducers and on ANY fibreglass boat I will epoxy it inot the bottm of the boat not hang it off the transom....

As far as silicone maine silicone dries hard and maintains a better seal over the life of the boat.......Ordinary silicone which will do the job lossens of after a few years and will allow water to get into the holes and then the transom and if the transom has wood in it that is not a good thing....
Spend the extra money and get good MARINE silicone.....

ALSO before driiling MAKE SURE there is nothing behind the holes to interfere with attaching the motor bracket...use good stainless bolts and LOCKWASHERS

[teabag]

As for the motor bracket, I have made a template out of aluminum for the backside of the transum as big as i can get it to fit in. This way i will be going through transum but putting more of the motors stress (torque)
on the aluminum plate than the transum> I am also placing some bicycle
tubing inbetween motor bracket and transum to absorb some of the vibration from motor to also aid>

[fisher]

If you can use "through the hull" method, that will be your best bet, careful with choosing the location, and use proper transducer epoxy, once set, its very hard(if not impossible) to remove without some damage.
but if you must drill and install a transom mounted transducer, use 3M Marine Adhesive Sealant 4200, above/below water rated, available @ CT boating section, expensive stuff but that is what it is designed for and worth every penny, after you drill, fill the holes and coat the entire length of screw with it and then tighten,
It is NOT silicone, don't confuse the two, silicone will deteriorate (specially below water) over short time and then you have leaks.

[teabag]

I will go and look at that 3M stuff as I really don't feel like testing out my auto bilge pump.
Thankyou all for this advice and I will have to let you know how it goes.
ya like maybe in a couple of weeks in the water. I use this 3M stuff and I go up to my cottage on wheels and find it, but no boat.
Well we now have proof on who we are all going to hate now won't we.
Along with the pump company eh.
Just kiddin around.
really my wife loves my humour.
Thankyou to all who had info and I hope your fishing is almost as good as mine is.
Jay