Centaur Keel Diagnosis

[Jcorstorphine]

thank you for this...

the boat will be ashore when I find it

is there any advantage to be had from scraping away at the join a little from the outside and shoving and smearing some sikaflex around the joint.

if so... which one


I mean this one looks pretty horrible?

http://www.keepturningleft.co.uk/wp-content/uploads/langstone-keel-1-1024x405.jpg

In my more affluent days (just before the kids went to University and then started buying their own homes ) I had a 1979 Westerly Pentland and had a good look at the keels but for some reason, the Centaur's big sisters did not seem to share the same issues, perhaps the keel width was greater so the keels did not flex as much.

In my Westerly there was no real space to inject some "jollop" between the keel and the stub.

However, I have seen one Centaur and it seemed to have a 50 mm flexible band round the joint which was about 3 mm thick which might be a good way of making a seal but I think you would also have to nip up the keel nuts as well.

 

[Seajet]

You could do worse than ask Chrissie, the surveyor on these forums; she checked the internal keel reinforcing on a friends' 1978 Centaur ( it was fine ).

My father reinforced the keels of his 1978 Centaur internally, with transverse wooden webs very solidly glassed in; the keel bolts still weeped and creaked very slightly as the boat went up and down on her soft mud mooring - despite Dad using a box spanner with a 6' tommy bar ! - but it wasn't a problem, less than a lot of boats get by condensation.

I always understood early Centaurs had a heavier grp layup, but suffered in other ways like crude hatches.

That being said, a chum at my club - also an engineer - had an early Centaur and the gap at the leading edge of the keel joins always opened a few millimetres when she was hanging from the crane, he did everything he could think of and it nearly drove him nuts but the simple fact was it was just a cosmetic thing, nothing to worry about in reality.

In contrast, I've seen a Hurley 24/70 with the fin keel literally wobble like a jelly when the boat was in the hoist, a small crowd used to gather, ' Hey look at this ! ' - now that was something I would worry about !

 

[JumbleDuck]

if they leak a little and wobble not at all can I slap jollop on the outside and jollop on the inside to slow up the leak?

You could clean out the gap round the outside and squirt some sealant it. Inside I'd suggest removing the nuts one by one (I presume they are nut on studs moulded into the keel) and reseal them with some cotton caulking. If you just had a small leak from one or two nuts you could identify which with the old talcum powder trick and then remediate as required.

Overall, though, a leak might be irritating but it's not the end of the world. It's damaged layup, either from flexing or overtightening, which you need to beware of.

 

[JumbleDuck]

In contrast, I've seen a Hurley 24/70 with the fin keel literally wobble like a jelly when the boat was in the hoist, a small crowd used to gather, ' Hey look at this ! ' - now that was something I would worry about !

 

[Twister_Ken]

I mean this one looks pretty horrible?

One for the scrappie, I suspect

 

[VicS]

In my more affluent days (just before the kids went to University and then started buying their own homes ) I had a 1979 Westerly Pentland and had a good look at the keels but for some reason, the Centaur's big sisters did not seem to share the same issues, perhaps the keel width was greater so the keels did not flex as much.

In my Westerly there was no real space to inject some "jollop" between the keel and the stub.

However, I have seen one Centaur and it seemed to have a 50 mm flexible band round the joint which was about 3 mm thick which might be a good way of making a seal but I think you would also have to nip up the keel nuts as well.

I think you will find that the GRP stub onto which the keels are bolted are shallower in the W31 range than they are in the Centaur.

Its this GRP that fails NOT the bolts. That is why the repair is essentially strengthening the GRP and fitting stiffening webs.

See the repairs described in the WOA Yahoo discussion group!

 

[dylanwinter]

You could clean out the gap round the outside and squirt some sealant it. Inside I'd suggest removing the nuts one by one (I presume they are nut on studs moulded into the keel) and reseal them with some cotton caulking. If you just had a small leak from one or two nuts you could identify which with the old talcum powder trick and then remediate as required.

Overall, though, a leak might be irritating but it's not the end of the world. It's damaged layup, either from flexing or overtightening, which you need to beware of.

and the exterior jollop/sealant of choice is....

 

[Searush]

(snip)

I mean this one looks pretty horrible?

Why? It's pretty solid cast iron and only lost a fraction of its thickness. I'll bet the GRP has taken up enough water to compensate for the weight loss thro rust. Just hire a needle gun for a day & give it a real good battering, Primocon it then fill & fair with resin/ powder mix and antifoul. It will look lovely and sail fine and probably last for 10 years.

I did something similar for SR but didn't bother to fair it off much, just filled a few voids I found after the needle gun treatment, it still looks fine after 4 years. It is only cosmetic really.

 

[dylanwinter]

Why? It's pretty solid cast iron and only lost a fraction of its thickness. I'll bet the GRP has taken up enough water to compensate for the weight loss thro rust. Just hire a needle gun for a day & give it a real good battering, Primocon it then fill & fair with resin/ powder mix and antifoul. It will look lovely and sail fine and probably last for 10 years.

I did something similar for SR but didn't bother to fair it off much, just filled a few voids I found after the needle gun treatment, it still looks fine after 4 years. It is only cosmetic really.

the keel looks pretty bad - but the joint looks fairly tight

of course the boat might be full of water after standing for a few years

I am trying to contact the owner

any Langstone people on here who could contact the berthing master for me

D

 

[JumbleDuck]

and the exterior jollop/sealant of choice is....

For filling a shallow groove I'd use Sikaflex. For general bedding of things I prefer polysulfide (Boatlife Lifecalk).

 

[prv]

Why? It's pretty solid cast iron and only lost a fraction of its thickness.

Mm, Kindred Spirit's little bilge fins were eroding similarly after a couple of years in the corrosive mud found in the upper part of the Itchen. The problem is metal-rich runoff from the scrapyard on the quay, which has been seeping into the mud for decades and setting up a galvanic playground. We had great nibbles almost an inch in diameter in the tips of KS's little feet.

Pete

 

[Seajet]

Dylan,

you are as capable as anyone else of contacting ' berthing masters ' & jollop applied externally is not the answer to anything anywhere, be it on boats, aeroplanes, girlfriends...

 

[dylanwinter]

berthing masters

Dylan,

you are as capable as anyone else of contacting ' berthing masters ' & jollop applied externally is not the answer to anything anywhere, be it on boats, aeroplanes, girlfriends...

sadly contact details for Langstone berthing master not available on the Langstone website

just a general email

I have emailed, dropped a note in the mail box and spoken to a club member... yet to make contact with the main man

open to other suggestions

as for jollop on the outside....if the keel is stiff but weeping it would seem to make sense to apply a suitable unguent used by others to stop the moisture from getting in

D

 

[aquaplane]

Or if it's only weeping mop it out now and then and live with it. Disposable nappies work OK if it's only a small leak.

Access on the B layout isn't bad, the only keel bolts there there is a little hassle to get to are the ones under the galley.

The ones on the Port side are a doddle, just take stuff out of the lockers under the seat. These could be more of a pain on an A layout though.

Look at Google Images, search "centaur keel bolts", the first three results show what they look like but I'm sure mine have more bracing than those.

 

[Searush]

Most of the water sitting in bilges drips in thro the stern gland. You will be eliminating that so it would take a really dodgy keel to fill the bilge of a Centaur in less than a month and I am sure that level of leaking would be glaringly obvious from a casual inspection, if only by severe staining and visible gaps!

For what you are planning, with ownership of just a few months (but don't be surprised if you decide you can't part with it after all) then a dob of bathroom sealant now & again would probably do. Even on the N of Scotland the tides are big enough to dry out & redo any sealant if it peels away.

 

[Swanrad2]

Occasionally these threads read like the old fella's tails in our local sailing club used to sound to me when I was young and even more inexperienced. You know the guys who talked of 'summer force 9's blowing up in minutes out in the bay against a spring ebb' or 'standing waves 30ft high on the bar' etc, etc. it was hard to tell what was scare mongering with those stories and it is hard to tell with some threads as well.

I'm sure Dylan can tell the difference between the 'old salt grizzling' and genuine advice posts - as for me, it just adds a niggle of worry to a night's sleep onboard! To summarise though - if your keels are bolted on the bolts are a point of weakness, if your boat is old (and especially if it is a popular/mass produced one) they are at risk, they will probably weep a bit, this is either a sure sign of a)impending doom or b)absolutely nothing, if they wobble about or flex then you definitely have a problem, if they don't then you must sleep with your left hand IN the bilge to ensure you don't develop a problem, fixing them is pointless and far too hard to contemplate and your time would be better spent repairing the Bimini on a far, far nicer yacht anyway. Fair, or have I missed anything?

 

[vyv_cox]

Westerly seem to have had something of a problem with providing sufficient GRP thickness around keel attachments. A couple of the very early GK29s suffered the keel punching right through into the saloon when the boat dried - mine was strengthened twice after the initial job done by the first owner was deemed insufficient. Not long after we started cruising, around 1988, a bigger bilge keel Westerly (33, 34?) sank on her mooring in the Menai Strait when a bilge keel tore off.

 

[dylanwinter]

Occasionally these threads read like the old fella's tails in our local sailing club used to sound to me when I was young and even more inexperienced. You know the guys who talked of 'summer force 9's blowing up in minutes out in the bay against a spring ebb' or 'standing waves 30ft high on the bar' etc, etc. it was hard to tell what was scare mongering with those stories and it is hard to tell with some threads as well.

I'm sure Dylan can tell the difference between the 'old salt grizzling' and genuine advice posts - as for me, it just adds a niggle of worry to a night's sleep onboard! To summarise though - if your keels are bolted on the bolts are a point of weakness, if your boat is old (and especially if it is a popular/mass produced one) they are at risk, they will probably weep a bit, this is either a sure sign of a)impending doom or b)absolutely nothing, if they wobble about or flex then you definitely have a problem, if they don't then you must sleep with your left hand IN the bilge to ensure you don't develop a problem, fixing them is pointless and far too hard to contemplate and your time would be better spent repairing the Bimini on a far, far nicer yacht anyway. Fair, or have I missed anything?

I have been on here long enough to cope with the scare mongering, negativity and welter of opinions formed without the benefit of experience or hard information.

The mood of the forum in the winter is often worse than the summer.

However, among the YBW posters are people who can usually be relied upon to offer good information or good sense.

I sometimes feel sorry for the optimistic new boat owners who come on here and post an inncoent question only to get the YBW Frasers wade in with their comments.



of course there are times when the pessimists are correct and it would have been better to have stayed at home and done nothing at all

as for looking for a better boat with a broken bimini - I would not be arsing about with dead Centaurs if £10K was as nothing to me

I would just buy a decent one in Scotland and get on with the family holiday to Shetland.

D

 

[ghostlymoron]

and the exterior jollop/sealant of choice is....

I did this a couple of times on my Mirage 28 as i had a slight weep. Raked out the top 10mm of sealant around the joint and refilled. I'm not convinced it did any good whatsoever. if you apply it when the boat is resting on it's keels, the joint is fully compressed. As soon as she's floating, the joint is extended (although not as much as when the windward keel is under stress). To be effective, a sealanted joint needs to be properly prepared and primed so the the sealant has a chance of adhering to the metal/GRP when under load. You can't really do this without removing the keel.
I eventually had both keels removed and re-bedded professionally at great expense!

 

[Swanrad2]

I did this a couple of times on my Mirage 28 as i had a slight weep. Raked out the top 10mm of sealant around the joint and refilled. I'm not convinced it did any good whatsoever. if you apply it when the boat is resting on it's keels, the joint is fully compressed. As soon as she's floating, the joint is extended (although not as much as when the windward keel is under stress). To be effective, a sealanted joint needs to be properly prepared and primed so the the sealant has a chance of adhering to the metal/GRP when under load. You can't really do this without removing the keel.
I eventually had both keels removed and re-bedded professionally at great expense!

This job was once described to me as follows. Dig two holes half the depth of the keels, have the boat lowered into them. Hoist goes away. Back fill the holes (maybe compress a bit). Remove keel bolts at leisure (or what passes as leisure when messing with studs and bolts of this size). On a quiet day have the boat hoisted off the keels and let her hang, go to work with angle grinders and a couple of mates cleaning off the old gunk, prime and re-bed. Lower the boat onto its legs and have the hoist go away again. Dig your boat out, hoist her up and fill the holes (might need a bit of permission I guess)

This description made sense to me - it isn't going to be gently varnishing your saloon table kind of work, but it it is understandable and doable, surely? Maybe a couple of hundred quid for the hoist owner and three days work at the right yard on a quiet week in the summer? Or is this completely understating the problem - the guy giving the advice had done the job (on a Macwester if memory serves), was he just lucky?