maintenance questions Ralph Osborn Koster

[udo]

Hello all,

Got some maintenance questions regarding the Ralph Osborn Koster I recently bought in Sweden on the West Coast.

(please find below also a link to an image gallery with the relevant images for my questions)


On recommendation of many experts and forum members I should check this winter the condition of the keel bolts.

Whilst the boat is now in the water, the engine is taken out for a major refurb, I have time to do some close-up inspections.

1. Looking at certain keel-bolts on the inside of the boat in the bilge, where some of them are constantly in the water, I still can't see any corrosion, so i wonder if these bolts are from stainless steel.

Knowing that the boat is made in 1967 and at that time no stainless steel was used, maybe the keel bolts have been replaced at least once?

Am I right here with my conclusion?


2. I see some dis-colouration and some cracks on the ribs in the bilge, but do not feel / detect softwood. Is there any concern or action I have to take?

3. There is also some water coming into the hull via underneath the propellor shaft. Not a lot, but I need to pump out water every day (couple of cm in the bilge) Reason for concern?

note:

Most water comes in via the stern and bow, but do not see water coming in via the keel bolts.


4. I would definitely do a major job on the under-waterline part of the boat this winter, still do not know if I go for an hempel or epifanes system, or any other.

any recommendations here?

5. What kind of material do I need to use for small (tiny) gaps between planks under the waterline?

6. In case I need to lift the boat 10 cm, whilst leaving the cast iron keel down on the ground, how do we lift the boat? At which points can we safely lift the boat (because usually the straps are going round underneath the cast iron keel.

Here is the image gallery:
http://dev.colourcertainty.co.uk/01Images/Sweden-Sailing-Boats/2010/TheBilge&keelbolts/


Many thanks for any feedback,

Udo

 

[Tranona]

Interesting set of problems and typical of boats of this age and construction. The keel bolts look like stainless. You will not see corrosion in the exposed bits. It will be in the threads inside the wood keel or where the bolt goes into the iron keel. It is called crevice corrosion and occurs when the metal is damp and deprived of oxygen. You won't know until you take them out. The rust stains from the joint are common and indicate water has got in, but a bit like blood - a little goes a long way and the water may not have got to the bolts.

The normal way of removing the keel is to prop the boat up with blocks under the keel with enough clearance to get the bolts out. Then take the nuts off and slowly split the joint and lower the keel. Your propping must be very secure. Lifting the boat off the keel is clearly not an option untill you can separate them enough to get the slings in.

The staining at the base of the timbers is commonplace - this area gets wet and eventually rots. The longitudinal splits are probably the result of alternate wetting and then drying.

I suspect after you have tried to deal with these issues, you might regret buying this boat rather than the first one with the sheathed hull, particularly as it had a Yanmar engine rather than that Vire!

 

[udo]

I suspect after you have tried to deal with these issues, you might regret buying this boat rather than the first one with the sheathed hull, particularly as it had a Yanmar engine rather than that Vire!

Hi Tarona,

Yes, but the boat with the sheathed hull was getting water in via the keelbolts and maybe also other places and that was an extremely bad sign.

The Vire Engine is now completely taken apart and refurbished and for
€ 1500 got basically a new engine on which I can reply the next many years.

Thanks for the feedBack!

Udo

 

[pyrojames]

Generally everything looks pretty sound, and I suspect the rust streaks on the keel are from the keel rather than the keel bolts. Keel bolts tend to give discrete rust patterns at each bolt, where as you have more distributed rust along the aft section of the keel only. You don't really need to drop the keel off, you should be able to drive out 2 or 3 bolts and check them. If they look OK, knock them back home and then test some others a couple of years down the track.

The leak under the prop shaft desrves some more consideration. It really shouldn't be leaking there!

The discolouration in the timber seems to be around a bolt through, what appear to be extra stainless straps on the inside of the frames. Rather od, and it suggests a craking problem with the frames at the turn of the bilge. I'd be inclined to remove the one which over the discoloured timber and see what lurks beneath.

The leakage you have sounds pretty mild, but as it appears to be limited to specific points you should be able to sort it out.

 

[udo]

Generally everything looks pretty sound, and I suspect the rust streaks on the keel are from the keel rather than the keel bolts. Keel bolts tend to give discrete rust patterns at each bolt, where as you have more distributed rust along the aft section of the keel only. You don't really need to drop the keel off, you should be able to drive out 2 or 3 bolts and check them. If they look OK, knock them back home and then test some others a couple of years down the track.

The leak under the prop shaft desrves some more consideration. It really shouldn't be leaking there!

The discolouration in the timber seems to be around a bolt through, what appear to be extra stainless straps on the inside of the frames. Rather od, and it suggests a craking problem with the frames at the turn of the bilge. I'd be inclined to remove the one which over the discoloured timber and see what lurks beneath.

The leakage you have sounds pretty mild, but as it appears to be limited to specific points you should be able to sort it out.

Many thanks for your feedback!

Regards,

Udo

 

[dur]

I think the timbers are laminated and the cracking - from wetting and drying or just permanent wet - is where the glue line has failed. I wondered if the timbers are ash which would go black if left in the wet but I guess they are oak. You could try using a lever to see if they will close up with a little pressure on them, but don't overdo it! If they do then you could work some glue in using an artists pallet knife or similar and shut them up again. If they don't close and there is no sign of softness you could syringe in some thickened epoxy - as much to waterproof as to reinforce. You must get it properly dry if using poxy though.

Isn't stainless unusual for keelbolts because of the risk of crevice corrosion as mentioned? Stainless steel need oxygen to stay stainless and without can corrode very quickly. Ususally iron bolts with iron keel? Maybe it is different in the cold Baltic.

Nice boat by the way

 

[tillergirl]

"On recommendation of many experts and forum members I should check this winter the condition of the keel bolts".

I am not convinced I would check the bolts this year although I suspect that the bolt through the floor immediately in front the engine water intake is the prime cause of that line of rust at the aft end of the keel. I accept that Pyro has a point about the 'distributed' nature of the rust, and my experience (with a wasted bolt that had parted) was exactly as he describes. I just feel there is too muct rust for it to general weeping. Mind you the engine is out and there is therefore an opportunity. That is going to be quite a long bolt. It is also a surprise to me that they are stainless - not sure I would like that


"1. Looking at certain keel-bolts on the inside of the boat in the bilge, where some of them are constantly in the water, I still can't see any corrosion, so i wonder if these bolts are from stainless steel."

My experience is that the condition of the visible bits of the keel bolts is pretty irrelevant! The best nut was the worst bolt! And the worst nut was the best bolt! Mine you that was mild steel, not stainless but its the potential oxygen deprivation that is th worry.

"Knowing that the boat is made in 1967 and at that time no stainless steel was used, maybe the keel bolts have been replaced at least once?

Am I right here with my conclusion?"

Probably. Keel bolts in wooden boats need to be checked regularly. I think TG has had 4 sets since 1964 (I've put two in).


"2. I see some dis-colouration and some cracks on the ribs in the bilge, but do not feel / detect softwood. Is there any concern or action I have to take?"

The timber needs some protection from water down there. Dry this winter and coat with something. I would be priming and using a bilge paint but it's for you to decide about the varnished finish there.


"3. There is also some water coming into the hull via underneath the propellor shaft. Not a lot, but I need to pump out water every day (couple of cm in the bilge) Reason for concern?"

Stuffing box needs repacking or at least adjusting to stop the leak there. The inner bearing needs to be removed and rebedded to stop that leak; it needs to be removed to check that is the source of the leak 'below the shaft'. You have also some seams to do! Those arrowed have sent you a message - damp around the seam + the weepy marks. I assume she is carvel? Or is she glued. Either way those seams need attention. If carvel, caulking cotton and read lead putty. Rake out the seam removing all old stopping, allow to dry, prime the seam, recaulk with fresh cotton - some I think prime again, apply red lead putty. If the seam is glued, I have no experience. The difference is that a carvel seam is a V shape - timber meets at the back edge and the seam is made watertight by the cotton and putty. A glued seam is just that two plank edges glued together. Of course there was no epoxy in 1967 so it would be resorcinol glue which might be coming to the end of its life.

Totally agree with dur on the laminated frames. Those gaps must be closed to water access. I doubt there is a risk as to strength but I would dry them thoroughly and try to epoxy glue them by using a wedge between the frames.

"4. I would definitely do a major job on the under-waterline part of the boat this winter, still do not know if I go for an hempel or epifanes system, or any other." I have used Blakes now Hempel for 27 years and now have abandoned them above the waterline at least in favour of Epifanes. Their yacht enamel is in my view enormously superior to the Hempel product which over the years has become (it seems to me) far more intolerant of weather conditions and gives a finish that is not as good. That's their enamel. The varnish is also in my view better. I have not yet used Epifanes under the waterline but may do this winter if I go for a tidy-up of the bottom as planned.


"5. What kind of material do I need to use for small (tiny) gaps between planks under the waterline?"

Answer above

"6. In case I need to lift the boat 10 cm, whilst leaving the cast iron keel down on the ground, how do we lift the boat? At which points can we safely lift the boat (because usually the straps are going round underneath the cast iron keel"

Don't take the keel off yet. That looks a totally extreme response to limited problems.

I'd knock out that keel bolt through that aft frame first and take stock of the situation. If it is ok, I'd be tempted to leave the others alone. If its rubbish then perhaps a look at the others is called for but I'd be tempted to dry up the aft end by the inner shaft bearing and the stuffing box, do that one bolt and the dodgy seams and she how that impoves dryness.

I like the boat.

Oh yes - and I would probably look closely at the outer end of the prop shaft. If water is leaking at the inner end its travelling up from the outer end outside the shaft tube and finding its way out through poor bedding of inner bearing. So rebedding the outer bearing will also be handy.

 

[Lakesailor]

As Pryojames says the rust is from the keel not the bolts. The delaminated ribs are something to watch, but better than cracked ribs, which most boats seem to collect.
Maybe see if you can stop the water ingress from beneath the prop shaft.

Otherwise. Don't get too anal about it. Review next year and compare.