Hi Jacko, the boat I am restoring had similar issues when I started, if the Hull is still attached to the inner frames then it should work out okay.
It will need you to strip the paint,back to the wood if you want a lasting repair.
Step 2 will be hard but well worth the effort, either using a rotary file/dremel type tool or a saw you will need to run it down the split about 3 to 4 mm deep.
Step 3 using a good 2pack epoxy like Bond Together from poundland, fill the slot with the glue making sure that its right down full depth.
Leave to fully cure for 24 hours then sand back to shape.
Step 4 coat the Hull in Ezekote resin and fine glass cloth. This will strengthen the whole hull. I usually use 4 coats of resin.
Step 5 using your usual methods you can now rub down, prime and paint.
Good luck, don't hesitate to ask if you need more help.
Cheers Colin.

looks like its delaminating inside as well marked the outside damaged area looks like a big job will need to remove part of the keel fit new bits and will fiberglass over the repair help

"only a baby boat"
Cheeky b*ggar!😠
Remember Captain - Commodore Promotion Board will be sitting soon!!
You're right though, internal access is the main problem🤔
Thanks to that big box at the core the only direct access to the inside of the hull is in the main cabin - unless you want to conduct major surgery😮
Good luck Jacko🤞 looking forward to the 'case photos' from the Scene of Crime!
Cheers, Doug 😎

Eye-eye sir, but thats only a baby boat.
But being an aerokits it will be fairly easy to work on, especially if its still good wood.
Interior access is the hardest bit.
Goodnight and Cheers Colin.

will post pictures in morning

A Sea Scout restorer might have an idea or two as well Colin👍
Pictorial credentials, before & after, attached😉
But first we need to be able to see the problem as you say.
Cheers, Doug 😎

Post some pictures and I'm sure between us commander restorers we'll think of a way.
Cheers Colin