Drilling holes in fiberglass

[j1r11]

Re: Drilling holes in fiberglass

Transducer should be mounted on the Starboard side , correct?

 

[TruckDrivingFool]

Re: Drilling holes in fiberglass

So long as its not in a spot in line with the prop (that could add to ventilation) the side doesn't matter. I usually let cable length and head unit location dictate.

 

[smokeonthewater]

Re: Drilling holes in fiberglass

yep put it anywhere that it will be in the water at speed ..... don't put it directly behind anything that will make the water turbulent or directly in front of a prop but otherwise wherever..... some guys have several of them all across the transom

 

[j1r11]

Re: Drilling holes in fiberglass

In my post #11 above it has a pic. Would the best place be on the inner or outer transom?

 

[TruckDrivingFool]

Re: Drilling holes in fiberglass

I'm guessing at a good spot being on the inner transom about centered between the drive and where it steps out. But it's hard to tell from the angle of the picture. Also hard to know (for us) is how the water breaks off the transom when the boat is on plane. Could you post a straight on picture of the transom from straight behind the boat? Maybe a down below type shot.

 

[j1r11]

Re: Drilling holes in fiberglass

I'm guessing at a good spot being on the inner transom about centered between the drive and where it steps out. But it's hard to tell from the angle of the picture. Also hard to know (for us) is how the water breaks off the transom when the boat is on plane. Could you post a straight on picture of the transom from straight behind the boat? Maybe a down below type shot.

That's kind of where i was hoping to mount it, so my bunk is not in the way. I will post another pic. in the morning. I have not had it in the water yet to see about what the water looks like back there and none of my launches have their docks in yet.

 

[joewithaboat]

Re: Drilling holes in fiberglass

My transom looks similar to yours, with a step. Mine is mounted halfway between the drive and step on the port side, about 8 inches from the drive. It came like that and seems to work well and not in the way of anything.

 

[j1r11]

Re: Drilling holes in fiberglass

My transom looks similar to yours, with a step. Mine is mounted halfway between the drive and step on the port side, about 8 inches from the drive. It came like that and seems to work well and not in the way of anything.

Thanks, i think that is the spot i am going for. Now if i could just get up the courage to drill or go the glue on starboard route.

 

[j1r11]

Re: Drilling holes in fiberglass

Different situations require different solutions,

For the transducer holes it'll depend on where you drill them. Most of time there will be the transom wood there to back it up so you can just drill and screw. Make you seal them good with 3m 5200 or 4200 to avoid water intrusion into your transom wood though to avoid leading to a rotted transom. Many say the best bet is to drill your holes over size, fill them with resin, then do your mount holes. this gets you transom wood sealed with resin and in theory avoids all chances of rot. Many do the first option.

For the gunwales your best option is to use a machine screw,washer, and nut with a metal backer plate to spread the load out. another option is to use screws with a wood backer but once again you'll need to deal with sealing it up good or sooner or later you'll be redoing it due to rot.

Does using a 1/2" screw and doing the bevel for cracking filled with 5200 sound right? Do i apply the 5200 into the hole and let it dry, or put it on the screw wet then screw it in?

 

[joewithaboat]

Re: Drilling holes in fiberglass

Does using a 1/2" screw and doing the bevel for cracking filled with 5200 sound right? Do i apply the 5200 into the hole and let it dry, or put it on the screw wet then screw it in?

5200 in hole, put screw in while wet. I always try not to drill all the way through the transom, just a bit deeper than the screw.

 

[TruckDrivingFool]

Re: Drilling holes in fiberglass

5200 in hole, put screw in while wet. I always try not to drill all the way through the transom, just a bit deeper than the screw.

Also use a toothpick or something small to smear the 5200 around in the hole to get it good and coated in there. I'll also leave a bit of a blob on the outside, put the screw in and tighten. Then clean away the excess.

 

[j1r11]

Re: Drilling holes in fiberglass

Thanks, i think i am gonna go for it How long of a screw do you think i can use without going all the way through?

 

[joewithaboat]

Re: Drilling holes in fiberglass

Thanks, i think i am gonna go for it How long of a screw do you think i can use without going all the way through?

Every transom will be different... the outer portions, away from the drive, of mine are only about 7/8 thick. I would think the screws that came with the unit will be fine. Didn't you say they were 1/2 inch long. The screws will be stronger than the plastic part you are mounting, so no need to over do the screws.

 

[sasto]

Re: Drilling holes in fiberglass

Thanks, i think i am gonna go for it How long of a screw do you think i can use without going all the way through?

If she were mine...I would go a half inch into the fiberglass. I would be using a #8 Stainless Steel pan head screw, a 9/64ths drill bit, a countersink. and some 5200.

No worries, mate!

 

[j1r11]

Re: Drilling holes in fiberglass

OK. How about for the transducer wire hole? Should i drill the hole as high as possible on the transome above the transducer? Fill that with 5200 also?

 

[smokeonthewater]

Re: Drilling holes in fiberglass

yep, drill the hole for the wire way above the water line if possible and use a stainless clamshell over it, seal it with 5200 ONLY if you don't ever intent to remove the wire intact. If you think you may want to pull the wire out, seal the clamshell with 5200 and seal the wire ONLY to the outer skin and the inside of the clamshell with silicone (easy to remove) or 4200 (harder to remove but easier than 5200).

 

[j1r11]

Re: Drilling holes in fiberglass

I finally drilled the holes, but did not fill them yet because it is supposed to be cold the next few days. Do i have to be careful about the curing time and temp w/5200? Directions say above 40 degrees when applying, but does that mean all 7 days above 40?

Also, i still have to drill my transducer plug hole. It will have to be about 1/2" hole. How do i know where my waterline is without putting it in the water? Would it have to be in the blue above? Transducer is where the red outline is.

 

[smokeonthewater]

Re: Drilling holes in fiberglass

Run your wire through as high as you can stand it

 

[j1r11]

Re: Drilling holes in fiberglass

Run your wire through as high as you can stand it

The highest possible would be in the blue line on the front the swim deck. It would not look as good as under the swim deck, but i want to make sure it stays out of the water. Would that be your choice as well?

Should i be using a tiny hole saw for a 1/2" hole, or a drill bit?

I will be putting a clam shell on the outside if the hole, but i just rest the wire on the fiberglass then fill it in w/ silicone, or is there some plug or sleeve i should use for the wire, then fill it in?

 

[joewithaboat]

Re: Drilling holes in fiberglass

This will likely be a thick part of your transom...
If you don't already have a newish, sharp, 1/2 inch drill bit... buy a new 1/2 spade/paddle bit. I sometimes drill an 1/8 inch hole (easy to drill straight) then follow with the spade/paddle bit. The sharp tip of the paddle will follow the 1/8 pilot nicely. Use moderate pressure on the gel coat. Drill the pilot hole from the outside, then also from the outside 99% through with the 1/2 inch, finish off the hole from the inside to avoid a blowout.

http://www.homedepot.com/h_d1/N-5yc...langId=-1&keyword=irwin 1/2 bit&storeId=10051