TOPIC: Transom Mount Hole Question

Hi folks. One more question for today, please.

Seems as though the previous owner drilled new holes in the transom for the new motor. Yikes! The new holes are 9-3/8" from the top of the transom. The old holes are 8-3/4" from the top of the transom. I shifted the motor to the right so you can see the holes in the photo.

Question 1: Obviously I will need to fill one set of holes. He had caulk in these before (double yikes!!!!). What product/method is best to fill these?

Question 2: Does anyone have any idea what brand motor was originally on the boat judging by the original mount holes of 8-3/4"?? Seems to be a strange number. The new motor is an '82 merc 500.

Thanks!

Some of the older motors had a different bolt pattern before everyone went with the new (BIA) pattern, not sure when the "change" occurred but that's likely what the other holes are from.

The best method (In My Humble Opinion) is to soak some hardwood dowel rod of the appropriate size in resin and drive the dowel into the hole. Let it set up, trim the ends and seal with some thickened resin. If a true "finished look" is desired, you can then fair the repair and paint or apply gel coat. Since it will likely be covered by the transom mounts it will probably not be seen anyway.

Another finishing option is installing a thin aluminum or stainless transom plate where the outboard contacts the hull. It will cover the repaired area, as well as protecting the outer finish on the transom from further damage by the outboard. Just a couple thoughts.......

(Look about 1/2 way down the page) www.fiberglassics.com/glassic-forums/home/member-projects/new-project-71-glastron-gt-150/page-2

Thanks Mark. Great advice. I have some west systems left over. I'll soak a dowel rod, press it in, and trim.

By the way - Nice job on the Tron!!!!

Ditto on what Mark said, I've done this several times. He beat me to the punch on this one

Yep that's the way to go

Bob

The (2) holes suggest to me that at some time in the past the owner may have raised the Merc (definitely the 'foot-print' of a Merc) up a smidge on the transom in a effort to get better performance.
You may want to check your cavitation plate height before deciding which set of holes to fill.
doc

Thanks Doc. The original owner swapped motors prior to selling to me, so I'm fairly certain it's just a matter of bolt hole location.

Interesting point though. So, raising the prop would loosen her up I assume?? I never thought of it on full size boats (I race RC hydros).