There's an old sea song called " The Golden Vanity " in which the ship's boy dives underneath the boat of the Turkish enemy, drills three holes, and sinks it, thereby saving the day. So now I'm getting ready to do the same thing to my own boat? I need to mount a bracket for a motor hoist on the transom (happily above what should be the water line the vast majority of the time) of my Hunter 335. I need to drill a couple of holes for through bolts. I want to do this in such a way as to not split the gel coat and I obviously don't want a leak. Any advice? Gary Wyngarden S/V Shibumi H335
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Jim Ewing
Drilling
I'm assuming you can get to both sides of the transom and there's not a liner in the way. You shouldn't have any problems with the gelcoat cracking from the drilling but you might if it flexes under the load when you use your lift. If the transom is cored drill an oversized hole and fill it with expoxy and fibers this will help keep water away from the core. Then drill the proper sized hole and goop it up with sealant when you mount the bolts. If it's not cored just drill the correct size holes but be sure to use a sturdy backing plate to reduce flex and spred the load. Jim "Prospect"
I'm assuming you can get to both sides of the transom and there's not a liner in the way. You shouldn't have any problems with the gelcoat cracking from the drilling but you might if it flexes under the load when you use your lift. If the transom is cored drill an oversized hole and fill it with expoxy and fibers this will help keep water away from the core. Then drill the proper sized hole and goop it up with sealant when you mount the bolts. If it's not cored just drill the correct size holes but be sure to use a sturdy backing plate to reduce flex and spred the load. Jim "Prospect"
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Trevor
Go slow...
I don't know what size holes you will be drilling, but I recently installed one of those Kingsprit bow rollers by Land2c (see guest forum). Luckily I had Tim, the manufacturer, with me to supervise. The only real advice is to use light pressure and high speed on the drill. If you see fiberglass bits around the drill you are making progress. I drilled 1/2" holes in the bow for the struts with no problems. Now that I feel confident drilling small holes I have to get the courage to drill *big* holes for my windlass project! Best of luck, Trevor
I don't know what size holes you will be drilling, but I recently installed one of those Kingsprit bow rollers by Land2c (see guest forum). Luckily I had Tim, the manufacturer, with me to supervise. The only real advice is to use light pressure and high speed on the drill. If you see fiberglass bits around the drill you are making progress. I drilled 1/2" holes in the bow for the struts with no problems. Now that I feel confident drilling small holes I have to get the courage to drill *big* holes for my windlass project! Best of luck, Trevor
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Dave
Drilling Holes in Glass Reinforced Plastic (GRP)
A couple of tips when you drill hole....you should be able to go thru the gelcoat fine without any problem but when the drill breaks out on the opposite side you will likely get a ragged edged hole where it fractures around the edge. A good way to prevent this is to clamp a piece of wood or plastic or some rigid material against the surface so that the drill is still cutting as it exits the GRP material. In a sense you are fooling the drill into thinking it is still deep in the cut even though drills don't really have a brain and can't think. When you remove the backing material you will find a nice clean hole. On both side use a much larger drill to countersink the holes to break the sharp edge and to give a space under the bolt head for the bedding compound to fill in and provide good sealing (keep the countersink diameter smaller than the head of the bolt or nut!!! As stated previously use a large backing plate preferably of stainless steel on the inside to distribute the load over as big an area as possible. Dave
A couple of tips when you drill hole....you should be able to go thru the gelcoat fine without any problem but when the drill breaks out on the opposite side you will likely get a ragged edged hole where it fractures around the edge. A good way to prevent this is to clamp a piece of wood or plastic or some rigid material against the surface so that the drill is still cutting as it exits the GRP material. In a sense you are fooling the drill into thinking it is still deep in the cut even though drills don't really have a brain and can't think. When you remove the backing material you will find a nice clean hole. On both side use a much larger drill to countersink the holes to break the sharp edge and to give a space under the bolt head for the bedding compound to fill in and provide good sealing (keep the countersink diameter smaller than the head of the bolt or nut!!! As stated previously use a large backing plate preferably of stainless steel on the inside to distribute the load over as big an area as possible. Dave
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Dakota Jim Russell
Use 5200 and don't turn the bolts.
Use 5200 to seal the holes and coat the bolts before inserting them into the holes. Don't turn the bolts when tightening them. Only turn the nuts. If you turn the nuts, you will find that you have developed an air leak that follows the thread . . . and you will have seepage. 5200 will provide an excellent barrier in this area. Jim
Use 5200 to seal the holes and coat the bolts before inserting them into the holes. Don't turn the bolts when tightening them. Only turn the nuts. If you turn the nuts, you will find that you have developed an air leak that follows the thread . . . and you will have seepage. 5200 will provide an excellent barrier in this area. Jim
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LaDonna Bubak - CatalinaOwners
Use 4200
The concern with 5200 is that if & when those bolts finally do start leaking (years down the road), the 5200 could cause damage to the surrounding gelcoat when removed. 4200 will give the same sealant properties without the badass adhesive qualities. LaDonna
The concern with 5200 is that if & when those bolts finally do start leaking (years down the road), the 5200 could cause damage to the surrounding gelcoat when removed. 4200 will give the same sealant properties without the badass adhesive qualities. LaDonna
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Guest
4200 vrs 5200
Guess years down the road the boat will be someone else's problem. 5200 provides a very sold sealant - so good that it will take the gel off. So pay your money and take your choice . . . . Well whichever you chose, don't turn the bolts. <grin>
Guess years down the road the boat will be someone else's problem. 5200 provides a very sold sealant - so good that it will take the gel off. So pay your money and take your choice . . . . Well whichever you chose, don't turn the bolts. <grin>
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