Rick Stephens
Admiral
- Joined
- Aug 13, 2013
- Messages
- 6,118
Howdy everyone. I am new to the boat modding side of the forum, and new to fiberglassing things like motor mounts into my boat.
Here's the story: I have a 25 year old runabout that I lucked out when I bought, since I didn't know squat about how to prepurchase exam a boat. At least I lake tested it :^) And I did end up buying an SEI outdrive for it by the second year. Took me that long to come to the conclusion that the original one was not quite what the seller led me to believe.
Here I am several years later having made a choice - rebuild the 3.0L that is getting tired, or drop in the 4.3L and Alpha1 Gen2 outdrive that I bought in a donor boat for a project boat that never came to be. I choose the later as it is hard, like most boaters, to pass up popping in almost 100 more HP.
I have some needful questions for those with experience in this. While I have built or repaired all sorts of things with fiberglass, I haven't built motor mounts nor reconditioned a 25 yo transom to handle a jump from 130 to 225 HP. I have somewhat a plan, but would surely accept adjustments where deemed an improvement.
1) I plan to build up the motor mounts as a laminate, basically 5.5 inches wide by 4.25 tall. The stringers are a full 4.25 inch below what is needed for the V6 mounts. My intention is to laminate 3/4 ACX plywood strips, and one 1/4 in ply strip, with epoxy based laminating resin in a PB mixture using a little bit of 1/4 in chopped strand and cabosil to thicken. Then use the same PB mix to attach to the stringers. End result is about 3/4 in above floor level, but still fits inside the dog house engine cover. The stringers also get 1.5 inch width added under the new mounts, built the same way with 2 layers of 3/4 inch laminated together and PB'd to the side of the stringers and to the hull at the bottom. The motor mount bolts will basically be directly above the current stringer inside edge, but using 4in lag bolts would not reach or attach to existing stringers.
Plan is to use the same epoxy resin to lay in CSM layers over the mounts to tie into the stringers. 3 layers when finished. 4.5 inch lag bolts, 4 in into the wood, .5 in the liquid motor mounts on top, using 5200 to seal the bolts. If I use laminating resin to build my mounts and layer the CSM do I need to top it all off with a waxed resin?
2) For me what is beyond any personal experience is the 25 yo transom. It is in pretty awesome shape (no credit to me and my shoddy pre-purchase exam years back). Previous owners obviously never once let it stay wet. And I park it indoors always. Core samples show a bit of dark wood down around the last inch or so above the hull. The rest of the transom is dry and clean, like new. (first noticed the dark wet wood when installing trim tabs) This seems totally amazing as Bluewater doesn't glass the transom over on the inside. It looks to have been painted and left be. Even the transom plate to gimbal housing bolts came out with minimal rust. They were all in reusable condition.
Question here is, what to treat the transom with? The paint is thin, almost like a stain. Do I drill out the transom plate bolt holes and epoxy them before installing the Gen2 plate and gimbal housing? Do I rseal the whole transom with resin? Sand 'er off and lay in a layer of CSM, which seems excessive? I don't have a clue how to make it last another 20 years other than keeping it dry.
Thanks for any thoughts. Pictures are easy as I move forward. I'll post in a couple days.
Rick
Here's the story: I have a 25 year old runabout that I lucked out when I bought, since I didn't know squat about how to prepurchase exam a boat. At least I lake tested it :^) And I did end up buying an SEI outdrive for it by the second year. Took me that long to come to the conclusion that the original one was not quite what the seller led me to believe.
Here I am several years later having made a choice - rebuild the 3.0L that is getting tired, or drop in the 4.3L and Alpha1 Gen2 outdrive that I bought in a donor boat for a project boat that never came to be. I choose the later as it is hard, like most boaters, to pass up popping in almost 100 more HP.
I have some needful questions for those with experience in this. While I have built or repaired all sorts of things with fiberglass, I haven't built motor mounts nor reconditioned a 25 yo transom to handle a jump from 130 to 225 HP. I have somewhat a plan, but would surely accept adjustments where deemed an improvement.
1) I plan to build up the motor mounts as a laminate, basically 5.5 inches wide by 4.25 tall. The stringers are a full 4.25 inch below what is needed for the V6 mounts. My intention is to laminate 3/4 ACX plywood strips, and one 1/4 in ply strip, with epoxy based laminating resin in a PB mixture using a little bit of 1/4 in chopped strand and cabosil to thicken. Then use the same PB mix to attach to the stringers. End result is about 3/4 in above floor level, but still fits inside the dog house engine cover. The stringers also get 1.5 inch width added under the new mounts, built the same way with 2 layers of 3/4 inch laminated together and PB'd to the side of the stringers and to the hull at the bottom. The motor mount bolts will basically be directly above the current stringer inside edge, but using 4in lag bolts would not reach or attach to existing stringers.
Plan is to use the same epoxy resin to lay in CSM layers over the mounts to tie into the stringers. 3 layers when finished. 4.5 inch lag bolts, 4 in into the wood, .5 in the liquid motor mounts on top, using 5200 to seal the bolts. If I use laminating resin to build my mounts and layer the CSM do I need to top it all off with a waxed resin?
2) For me what is beyond any personal experience is the 25 yo transom. It is in pretty awesome shape (no credit to me and my shoddy pre-purchase exam years back). Previous owners obviously never once let it stay wet. And I park it indoors always. Core samples show a bit of dark wood down around the last inch or so above the hull. The rest of the transom is dry and clean, like new. (first noticed the dark wet wood when installing trim tabs) This seems totally amazing as Bluewater doesn't glass the transom over on the inside. It looks to have been painted and left be. Even the transom plate to gimbal housing bolts came out with minimal rust. They were all in reusable condition.
Question here is, what to treat the transom with? The paint is thin, almost like a stain. Do I drill out the transom plate bolt holes and epoxy them before installing the Gen2 plate and gimbal housing? Do I rseal the whole transom with resin? Sand 'er off and lay in a layer of CSM, which seems excessive? I don't have a clue how to make it last another 20 years other than keeping it dry.
Thanks for any thoughts. Pictures are easy as I move forward. I'll post in a couple days.
Rick
