replacing a STUMPNOCKER transom

I hate to break it to you but you aint gonna use that wood for a template!  ;D  Use better wood and newer nails to put it back in.   ;D

Leave the outer skin alone and rebuild from the inside.

 

Yeah that looks as tasty as one of my projects. I hate to say it, but have you checked the stringers for damage at the transom? I get to gut mine all the way. Yes, now would be the time to set transom height to match your motor if you plan on sticking with the longshaft. Eliminating the JP would simplify things and remove weight. Just make sure to tie the old skin in with the new section. I'll leave it to others to give you a good layup schedule for that. Might as well only cry once and get it all out of the way if you plan on keeping the hull. Or should I say itch scratch sneeze....

Swamp

 

May not be.  In the photos you posted it looks like there may be, but they look very small.  Those may just be battery "boxes" or whatever. Post a pic of the whole bottom especially at the transom.

I would not dream of replacing only part of a wooden transom, especially given the extent of your damage.  I'd replace the whole thing with high quality marine grade ply coated on all sides with epoxy at a minimum.  IMO wood and polyester resin are not a long term recipe for success, use epoxy.  Keep in mind epoxy will stick to polyester but not the other way around.  Many people don't want any wood in their boats and will go with foam core.  On a small boat like that I'd be comfy with the ply and epoxy. On a larger boat where the materials alone are going to cost $$$$ I'd go with foam core. But that's just me.  Some of the guys on here do this sort of thing for a living, they can give you the bottom line on what the professionals would do.  I'll admit I'm a hack with a little experience compared to some.

Good luck, I hope it will be a rewarding and successful project.

 

good advice - very good advice

polyester based resins are pourous,and provide a "surface bond",when used with wood

epoxy is allways the best choice,when working with wood...


nothing "wrong" with using wood,provided that wood is sealed completley with an epoxy


word to the wise:

the garboard plug is often the most overlooked area,it's best to drill that area out much larger than what's needed - fill that hole with epoxy/mixed with a thickening additive - i like west system 403 - it's an adhesive,after that mix kicks,drill the hole to the correct size

another tip:

allways coat wood to be laminated,with a coat of epoxy first - no additives,then spread the laminating mix


do not throw the epoxy mixing containers in the trash - as it kicks,it makes heat - enough to start a fire

a drawback to using epoxy is amine blush - some epoxy resins do not blush,others do - west system,what i use,it blushes - this needs to be removed with soap and water,before sanding...

a guy i know,mad mike,a nice gentleman,but,he has a problem - he believes his skill level is way beyond what it is - he borrowed some supplies from me before.he was attempting to make gutters on his boat - he laminated some parts with epoxy and attempted to use a polyester chop strand putty on top of that west system,without removing blush - he complained to me,"that stuff would not set","it's trash" - after i asked him a few questions,the problem was explained to him... :

 

When you say treated ply you aren't talking about pressure treated right? Pressure treated makes a lousy core.

 

See what??

If it were mine and I did not want to repair it right I would at least tear up the last foot or so and put the transom in down to the hull rather than the transom to the sole and replace the section after the transom is repaired so I could tackle that project at a later date. That would also be dependant on how rotten the sole is. If it looks like the transom, you need a bigger grinder than a Dremel.

On the 30th anniversary of the boat - wanna place a bet?

 

Okay that sounds like a good plan.

As far as getting rid of any rotten wood, I think you know the answer to that.  :'(

Remember your life may depend on the integrity of that boat even in calm weather.  You might be surprised what you find when you follow the rot.  A soft floor is not a good thing.  If installed properly a floor/sole is a working part of the hull, not just a place to stand.

Probably not what you want to hear.  Sorry. As Duck nut said though you may not need to take out the whole sole and can use butt blocks to join the old and new. You will end up doing some work twice if you cheat now though.

 

Good on ya. Like I say cry once not twice.

Have you checked this out? It' s a bigger more complex boat but the principal is the same. http://boatbuildercentral.com/howto/transom_repair/index.php

If you buy your materials from them they will make sure your layup schedule is correct and make sure any changes you want to make are structurally sound.

 

That is good news.

Need to drill spot holes and insert a moisture meter. You may be carrying a couple hundred extra pounds.

 

that wood -

it's never gonna dry out


seeing what you're pulling out,rotted wood,you're still gonna use a wood core ?

 

The clear indication that something is going on is that the glass over the top came off of the wood.  If everything was fine you would have ripped chuncks of wood off with the glass.  The glass has seperated from the wood - delaminated.

If you are not going to repair the floor then don't disturb the foam in the sides.  Leave it as it is and fix it when you do the sole.

BUT! when cut the sides and the sole back far enough that you can repair the transom from side to side and down to the floor and then bring the sides and sole back to the transom.  In essence two seperate repairs.  That way when you tear the sides and sole out you won't disturb the transom.