Re: my first boat 1962 mfg
The simplest check is to remove the 2 lifting eyes in the transom and poke around and visually check. See if you see "clean" wood or brown rot.
As was said previously, you could remove the aluminum trim cap on the transom and drill through the seal. My seal was tough stuff.
Knowing what I do from my project I would do this to check it out:
Assuming the engine is off, remove the aluminum "cap" or trim and using a 7/8" fly cutter (wood boring) bit drill several holes through the seal ... my seal was about 1/8" thick. I would make one hole on each side of where the motor mounts. Drill the seal just enough to get to the wood. Poke around the the wood and see if it's wet, brown, stinky and or rotten. If you find nice solid, clean looking wood I would simply make a batch of thickened epoxy and seal it back up.
If you find something that makes you suspicious, I would drill several more holes across the top and poke around and see what you can find.
If the news isn't good, here is the easiest way to remove the top seal without damage. Use a sabre saw and a sharp, medium tooth wood cutting blade that has been shortened so that the "down" stroke penetration is only about half an inch. (I shortened mine with an angle grinder.) Make a 3/8" hole at the edge of the seal without hitting the inner or outer transom skins, insert saw and carefully cut along the inner surfaces or the two skins. Some hand work may be required at the ends.
Now you have full access to the inner transom. Poke, sniff, drill and decide if it is solid or not. If you turn out lucky, re-seal the the top with epoxy thickened with cab-o-sil or something like it and you are good to go. The best part of this is you will remove any nagging thoughts about your transom. If it's good, ... it's GOOD!
If replacement is called for, re-read my whole thread. Niagaras are not that different from Oxfords. Remove the outer skin using the same short blade. Be sure to leave 2 inches of the outer skin at the edges.
It's not a bad job but expect to put 20 + hours (depending on your skills) and $150.00 worth of plywood and epoxy plus finishing materials. When you're done your boat will be better than new!
You must decide if you have the skill, tools and resources to tackle an job like this. I'd sure hate to see you disable your boat and get "stuck". Perhaps you should just investigate and unless the transom is terrible (like mine was) put the job on the back burner. Do some of the smaller jobs and build your confidence. Most importantly ... use and ENJOY your boat. If you must, disable it in the off-season when you can take your time on difficult repairs.
Why not start a thread on the MFG forum? Lots of help & info there.
Good luck! Looking forward to seeing your progress!
The only wood was in the transom. Does the floor seem solid with no mushy or weak spots ? If not check the transom out .If you have any doubt of it's strength you should take a 1/4 inch drill bit and drill some holes down low along the bottom of the transom. Drill thru the inside skin but not all the way thru to the outside. Look at the shavings .If they are good and dry you are probably OK . If they are dark wet and mushy then you will need to replace the transom. But don't worry the guys here can guide you thru all the steps involved .
