Not sure if this should go in the restoration forum or here. This issue could pop up with out actually doing a resto so I think it should be ok here.
I am new to boating so if I don't use the correct terminology please let me know.
I have a 1981 15' Sea Sprite bow rider that I bought with no motor. I could not find anything about what size motor generally came with these boats but judging from other boats of similar size I could have gone as low as 40hp and still moved the boat. A decent size would be in the 65-75hp range, this would probably give the boat enough power to get on plane fast and still be able to pull skiers/tubers without making the motor top out to do so. I ran across a great deal on a 1989 Evinrude 88 Spl so I figured it was plenty of HP, probably a little overkill but just a little. The deal was too good to pass up. I am now absolutely positive the boat originally had a smaller motor. The mounting holes on the boat are closer together, closer to the top of the transom, and there are only 2 of them. The motor has several different holes to choose from, for the upper mount point and the lower mount holes are actually slots. So I have 4 bolt locations to use and the footprint of the mount plate is larger. Lastly the top of the mounting plate has a pair of hooks to hang the motor on the transom...I have not noticed these on the smaller motors. I measured the gap between the tip of the hook and the mount plate and got 3", in other words the plate would slide perfectly on a 3" transom with no slop.
The transom on the boat is a single layer of 3/4" ply plus the hull and interior glassing totals approx 1" thickness on the transom. I am not 100% on what I should do. Either the hooks on the mount plate are there just to support the motor while thread the bolts and tighten everything down and the thickness of the transom does not need to match the hooks thickness.... OR.... I need to tear out the old ply and interior glass on the transom and replace it with several layers of ply (totaling about 2.5" thick) and then fiberglass the ply to the hull and add layers of glass to total 3" thick transom.
My logic and common sense tells me that a bigger motor needs a bigger transom to hold up to the extra umph put out by the motor.....plus replacing the transom means I know there are no soft spots or rot.
Thanks for the help.
DJ
I am new to boating so if I don't use the correct terminology please let me know.
I have a 1981 15' Sea Sprite bow rider that I bought with no motor. I could not find anything about what size motor generally came with these boats but judging from other boats of similar size I could have gone as low as 40hp and still moved the boat. A decent size would be in the 65-75hp range, this would probably give the boat enough power to get on plane fast and still be able to pull skiers/tubers without making the motor top out to do so. I ran across a great deal on a 1989 Evinrude 88 Spl so I figured it was plenty of HP, probably a little overkill but just a little. The deal was too good to pass up. I am now absolutely positive the boat originally had a smaller motor. The mounting holes on the boat are closer together, closer to the top of the transom, and there are only 2 of them. The motor has several different holes to choose from, for the upper mount point and the lower mount holes are actually slots. So I have 4 bolt locations to use and the footprint of the mount plate is larger. Lastly the top of the mounting plate has a pair of hooks to hang the motor on the transom...I have not noticed these on the smaller motors. I measured the gap between the tip of the hook and the mount plate and got 3", in other words the plate would slide perfectly on a 3" transom with no slop.
The transom on the boat is a single layer of 3/4" ply plus the hull and interior glassing totals approx 1" thickness on the transom. I am not 100% on what I should do. Either the hooks on the mount plate are there just to support the motor while thread the bolts and tighten everything down and the thickness of the transom does not need to match the hooks thickness.... OR.... I need to tear out the old ply and interior glass on the transom and replace it with several layers of ply (totaling about 2.5" thick) and then fiberglass the ply to the hull and add layers of glass to total 3" thick transom.
My logic and common sense tells me that a bigger motor needs a bigger transom to hold up to the extra umph put out by the motor.....plus replacing the transom means I know there are no soft spots or rot.
Thanks for the help.
DJ
