Advice requested - stained fibreglass

[PaulJS]

Hi everyone,

I'm seeking advice from more experienced boat owners.
I'm currently considering buying my first yacht and have found one that could be just what I want, but I have found a couple of things I'm not sure should make me run away from this particular boat.
She's a 40+ year old glass fibre bilge keeler and during my inspection I noticed that a portion of the hull between the bilge keels was stained dark brown, and on going inboard and lifting the saloon floor board I found the centre bilge filled with concrete. A further look around led me to suspect that the cross-over between the diesel tanks was, or had been leaking.
So, my questions are:-
1. Could diesel lying between this concrete ballast and the inside of the hull cause the glass fibre to be stained or would the proximity of concrete explain this staining?
2. If so, would this affect the strength of the glass fibre? (It certainly feels solid enough)
3. Is it normal to have concrete as a ballast in the bilges rather than just encapsulated in the actual bilge keel mouldings?

Any advice gratefully received.

Paul

 

[alahol2]

I have had the bottom of a previous boat stained brown/black from sitting in mud that was probably contaminated with oil. It did no obvious damage to the glassfibre.
As to concrete in the bilges, it may be worth mentioning the type of boat you are looking at. I can't say I've heard of any production boats that are like that from new but others may be able to advise.

 

[Seajet]

A 40+ year old grp twin keeler will be pretty poor design wise, compared to more modern boats.

Are the keels bolted on, or part of the moulding ? If the latter, the keels will have to be fairly vertical to enable removing from the mould, not good hydrodynamically.

That and the concrete internal ballast tends to make me think ' go and look elsewhere ' unless she's a terrific bargain and you really fancy her.

It's a buyers' market at the moment, lots of good boats going relatively cheap.

 

[PaulJS]

Yacht type

She's a MacWester Wight, as to whether or not it would be a terrific bargain is a moot point.
I'm pretty sure that the keels are part of the hull moulding and I'm aware that this won't help her sailing performance, but to be honest she ticks a lot of boxes for where I'll be sailing.

As an aside, how about this for a somewhat spooky coincidence... The evening I got home from inspecting her, with my head full of doubts about this hull staining, I picked up at random a couple of old issues (1976!) of PBO from a batch of about 50 that I bought a while ago, and to my pleasant surprise found that they contained a couple of articles about sailing in my home waters in the Solway Firth and then to my utter amazement found that the boat the writer was on was a Wight!
Now I am one of the world's greatest sceptics, but that definitely raised my eyebrows!

 

[Tranona]

Agree with those comments. Concrete in the bilges is not a good idea. Expect some previous owner has put it in to try and improve stability. Don't think any builder would have used that method. Needing additional ballast is an indicator that sailing performance is poor so maybe the boat is not a good design anyway.

 

[Tranona]

Now we know the boat, it is not a surprise that somebody has tried to improve its sailing performance. If I remember rightly the fuel tanks are moulded in and prone to leaks. The Wight has been covered a couple of times in used boat reviews in PBO. Probably worth contacting the owners association as there are many enthusiastic owners of the marque (although not a huge number of Wights were built).

 

[PaulJS]

I think that they've always been described as motor sailers, pure sailing ability never was their ultimate selling point!
From what I could see the fuel tanks were just two big steel tanks on either side of the engine bay, the suspected leak was where the copper cross-over pipe between them under the prop shaft had been comprehensively dinged.
If the concrete wasn't an original fitting it should be easy enough to remove as I don't imagine that it has bonded with the glass fibre of the hull.
I reckon that I will try to get in touch with the owners association to find out more info.

 

[Ben Dockrell 22]

Hello

Im a complete novice too

I had read about lightening strikes going through the mast jumping to the keel and when i read your post about concrete perhaps that could be why a previous owner might use concrete or buy a yacht with concrete as ballast, i dont know what the odds are for someones yacht being hit by lightning but it does appear to be something that people consider at times.

 

[Seajet]

Hello

Im a complete novice too

I had read about lightening strikes going through the mast jumping to the keel and when i read your post about concrete perhaps that could be why a previous owner might use concrete or buy a yacht with concrete as ballast, i dont know what the odds are for someones yacht being hit by lightning but it does appear to be something that people consider at times.

So, what part does the concrete play in a lightning strike then ?!

There doesn't seem to be a hard & fast solution to avoiding strikes or dealing with them, but dissipators - a bit like an upended wire brush at the masthead - and a strong conductive connection between keel & mast, ideally to a large plate on the side of a keel, seems about as good as anything.

I have a chain with a snapshackle, heatshrink sleeved to protect the topsides, which I clip onto the shrouds to trail in the water; to be honest I'm not sure if I'm making an easy path to get rid of the lightning, or making the boat more attractive to strike !

 

[PaulJS]

Hello

Im a complete novice too

I had read about lightening strikes going through the mast jumping to the keel and when i read your post about concrete perhaps that could be why a previous owner might use concrete or buy a yacht with concrete as ballast, i dont know what the odds are for someones yacht being hit by lightning but it does appear to be something that people consider at times.

I can't really see what benefit concrete ballast would provide in the event of a lightning strike - it's already arced through hundreds or thousands of feet of air so an extra few inches of damp concrete which would already be below sea level wouldn't stop it earthing to the sea.

I'm afraid that I can't really claim to be a complete novice either, I've worked at sea all my adult life, it's just these fibreglass matters that confuse me!

 

[Seajet]

PaulJS,

I'm sure the Macwester owners association is the place to ask; I'm not that familiar with the Wight, but the impression I have is of slow, solid boats - I'd be surprised if it's tender though, as would seem to be inferred by adding ballast.

I thought people would be doing everything possible to lighten them to get decent progress !

There is a keen Macwester owner here but I can't remember his forum name; may well be worth starting another thread asking for advice on Macwester Wights.

 

[PaulJS]

Good idea!

Thanks SeaJet, now that you mention it I do remember some posts from a Wight owner, so I'll start another thread.

Paul

 

[Ben Dockrell 22]

Hello Seajet and thank-you for your very educational input i do appreciate it

Paul i think working at sea is preferable to being stuck in an office!

If im honest about concrete it appears to be a good bet in terms of coming out of a collission when your hull is made of it, i prefer the idea of a concrete boat than a grp boat, a concrete hull with grp decks and cabin perhaps.

So, what part does the concrete play in a lightning strike then ?!

There doesn't seem to be a hard & fast solution to avoiding strikes or dealing with them, but dissipators - a bit like an upended wire brush at the masthead - and a strong conductive connection between keel & mast, ideally to a large plate on the side of a keel, seems about as good as anything.

I have a chain with a snapshackle, heatshrink sleeved to protect the topsides, which I clip onto the shrouds to trail in the water; to be honest I'm not sure if I'm making an easy path to get rid of the lightning, or making the boat more attractive to strike !

 

[Seajet]

Hello Seajet and thank-you for your very educational input i do appreciate it

Paul i think working at sea is preferable to being stuck in an office!

If im honest about concrete it appears to be a good bet in terms of coming out of a collission when your hull is made of it, i prefer the idea of a concrete boat than a grp boat, a concrete hull with grp decks and cabin perhaps.

Hi Ben,

ta for your kind words.

I know someone who had a very nice 35' ferro cement boat he'd built himself ( he's a serious engineer but the effort got to his health ) - I went across the Channel with him once, and he took her all over Brittany etc.

Ferro construction seems out of fashion now; it lent itself to big blue water cruisers rather than anything remotely sporty - my chum sold his a few years ago and bought a relatively light French fin keeler, much to my surprise.

I did read that ferro is unpopular with blue water cruisers now as people have found if a hole is knocked in it, say after hitting a coral head, one can't insert something to block the hole because the wire armature is in the way.

I did sometimes wonder about the lifespan of the mild steel armature...

Said chum had a problem in Holland when a protruding bolt in a lock knocked a hole clean through the hull; sure it's easily plastered over, but the cement shell is rather thin & brittle.

 

[William_H]

So, what part does the concrete play in a lightning strike then ?!

There doesn't seem to be a hard & fast solution to avoiding strikes or dealing with them, but dissipators - a bit like an upended wire brush at the masthead - and a strong conductive connection between keel & mast, ideally to a large plate on the side of a keel, seems about as good as anything.

I have a chain with a snapshackle, heatshrink sleeved to protect the topsides, which I clip onto the shrouds to trail in the water; to be honest I'm not sure if I'm making an easy path to get rid of the lightning, or making the boat more attractive to strike !

Hi Seajet regarding the chain from shroud into water. You would be far better off connecting the chain to the base of the mast rather than the shroud. Stainless steel has a relatively high resistance such that with any real current it will fuse or any small current it will lose its heat temper. Aluminium on the other hand has really low resistance such that a mast could carry huge currents without damage. I don't think you are making the rig any more attractive to lightning in doing so but apparently the fine tips of brush or spikes can attract and dissipate static build up earlier so possibly averting a strike. regards olewill

 

[CAPTAIN FANTASTIC]

Are you sure is a Macwester? Macwesters dont have central bilge; also the gap between floor sole and inside hull is no more than 5 inches hence no room for concrete or other fill. It is likely that the fibreglass has been discoloured. I have a Macwester sloop, Wight, and the fibreglass at midship inside is discoloured.

You are referring to the Diesel Tanks, both my diesel tanks are at the very end stern.

Macwesters are good yachts, the Wight has a lot of room, the Sloop version is very rare nowadays; they can take the weather without issues.

 

[PaulJS]

The boat is definitely a Wight, and when I referred to a central bilge I was talking about the central space under the cabin floor. I found the staining on the outside of the hull between the keels and tried to look inside to see if there was any sign of it, but found a big lump of concrete approx 8" wide and as long as the saloon, almost level with the top of the stringers. Anyway, further investigation found that the crossover between the fuel tanks seems to have been damaged, so I'm surmising that the fuel lay in the bilge between the fibreglass hull and the concrete for long enough and got absorbed enough to stain the outer hull... I could be totally wrong though!

 

[ukmctc]

The boat is definitely a Wight, and when I referred to a central bilge I was talking about the central space under the cabin floor. I found the staining on the outside of the hull between the keels and tried to look inside to see if there was any sign of it, but found a big lump of concrete approx 8" wide and as long as the saloon, almost level with the top of the stringers. Anyway, further investigation found that the crossover between the fuel tanks seems to have been damaged, so I'm surmising that the fuel lay in the bilge between the fibreglass hull and the concrete for long enough and got absorbed enough to stain the outer hull... I could be totally wrong though!

sounds like a rational choice, and believable so go with that, no water in the boat so safe and sound. nothing wrong with concrete as ballast, originally boats uses rocks and pig iron, and anything else heavy, you adjusted by adding or throwing it overboard.
Modern yachts, geez they can't even keep their keels on!

 

[BruceDanforth]

Hi everyone,

I'm seeking advice from more experienced boat owners.
I'm currently considering buying my first yacht and have found one that could be just what I want, but I have found a couple of things I'm not sure should make me run away from this particular boat.
She's a 40+ year old glass fibre bilge keeler and during my inspection I noticed that a portion of the hull between the bilge keels was stained dark brown, and on going inboard and lifting the saloon floor board I found the centre bilge filled with concrete. A further look around led me to suspect that the cross-over between the diesel tanks was, or had been leaking.
So, my questions are:-
1. Could diesel lying between this concrete ballast and the inside of the hull cause the glass fibre to be stained or would the proximity of concrete explain this staining?
2. If so, would this affect the strength of the glass fibre? (It certainly feels solid enough)
3. Is it normal to have concrete as a ballast in the bilges rather than just encapsulated in the actual bilge keel mouldings?

Any advice gratefully received.

Paul

There's lots of other boats about mate. If it looks a bit iffy just walk. I looked at nearly a dozen before spotting the right one for me.

 

[oldharry]

Concrete in the bilges of a GRP boat? WALK AWAY FROM IT.

Concrete can can react with GRP and cause massive failure, of which you will have little or no warning.

A nice little 17 footer in our yard had had 50kg of concrete poured into her bilge to 'make her a bit more stable'. Some time later it was decided she didnt need it (!) and the owner started chipping it out again - to find the GRP on which it had lain had been attacked and had become like soggy cardboard. The glass mat had of course survived, but the resin binder had failed completely. I have no idea what grade of concrete had been used or why this had happened. But be warned - it can and does!

DONT MIX Concrete and GRP!