Hi Udo,

It's difficult to see from the pics (got any closer-up?) but cracking in between the garboard plank and the keel (the garboard seam) is quite normal for a boat that has been sailed: the hull is flexible and the keel isn't so eventually it needs scraping out and re-caulking - not normally a big deal.

The wood rot on the other hand.. is it actually rotten or just soft? I would suggest scraping back ("burning") a large area to find out.

Frost.. The chainplate pics show signs of (fresh) water getting into the timber. Did you keep the boat under cover - or out in the cold white stuff??

She is still a stunning boat and definitely worth working on..

 

Indeed I will be scraping large area's, or maybe the whole hull below the waterline to find out what is going on. The end of the planks, which i consider not to be good are really very soft and could easily peel away wood with my finger. The so called dead wood underneath, made out of oak was also still very wet, still do not think that was having rot, just the mahogany.

I made a tent cover from new materials myself in october, so the boat was totally dry. +we had hardly any rain here. It was freezing from october right till the end of March. Lots of snow but no rain.

see here my boat cover (from image 15 onwards)

October2010

Udo

 

Udo, I still cannot get over what a stunning part of the world you live in!! Please don't come here - you would find it dull and uninteresting.

I would suggest scraping the entire hull below the waterline - or at least large parts of it until you get back to sound timber. It is definitely rot and not just frost damage? Mahogany planks on Oak frames is a very common method of yacht construction, so I doubt there is anything happening here that no-one has seen before. Are the plank fastenings (presumably copper) okay?

Try not to touch the soft timber - there are epoxy products (called CPES) around that can solidify the wood over small non-structrual areas.

 

I think I must have frost damage as well, since the wood is still extremely wet in some places at the end of a very harsh winter. yes, for sure.

 

You need to speak with a professional but I'm thinking "stop playing with it and let it dry out some". My timber boat knowledge is limited but I did once own a 90 year old timber launch which I had to largely take back to bare timber and recaulk the entire hull. Moisture in the timber looked much like this but it is moisture not rot. Your task now is to ensure that the wetness does not result in rot but I doubt your problems are as bad as you fear.

 

The ends of the planks are now badly damaged, so at least part of the planking needs to be replaced. That needs to be done extremely precisely since it's carvel build extremely tight seamed, no glue, just exact. maybe at this spot not too difficult, but still a reasonable job, not something I do in a weekend I guess.

 

So, we finally did bite the bullet and decided what to do:

Take away the bad stuff and take in in stages what to do.

Here are images from the first stage:

and I love it to take all the bad wood away!

renew some planking

Udo

 

All the garboards were rotten? Wow!

You've done the right thing, Udo - All the ribs and structural timbers seem ok in the photos and the boat will be drier and cleaner once the planks are back on.

Keep going! She'll be one solid boat when you've finished.

 

Sorry, no advice for you. With that said, current troubles aside, WOW what a beauty!!!

John

 

Hi John,

via these links you can see some more images:

Ralp Osborn Koster K 25 - Sweden

Index of /01Images/Sweden-Sailing-Boats/2010/Koster-project-web

Indeed, she is pretty. Last year I was just nearly blindly buying the boat without checking enough under the waterline, which I should have done. But now it looks like we are able to get it properly repaired, I am a lot happier.

Cheers,

Udo

 

Oddly enough as I read your posts I was thinking that checking in over at the WBF would be a good idea. It is great that you found someone to help you with the repairs.
Your boat is quite beautiful. Glad you will save her.

 

I am on a couple of forums and the WBF is one of them.
Reason? Since I am in contact with a few people over here in this forum.+ Jef is one of the most knowledgeable people I came accross, and to hear feedback from many people is always xtremeky helpfull.

So no reason to switch forum!

Cheers,

Udo