How Safe are Windows in the Hull

[lustyd]

if anyone really knows what the risk (probability) of a given fitting (be it hose, seacocks, windows etc) failing when you least want it to

I think that was Tranona's point above, the risk of it failing in action appears to be almost nothing or we'd be hearing about it regularly.

It's certainly a risk, and they do fail but it seems mostly when mechanical force is applied to a duff one which we hear about quite a bit. I don't imagine he was even arguing for the use of brass fittings, just saying that with proper maintenance they aren't the huge issue they're made out to be. I tend to agree but my boat does have TruDesign fittings so make of that what you will

 

[Pye_End]

this one was French

?

'RAPSCALLION (MMSI: 232045880) is a Sailing Vessel that was built in 2013 (10 years ago) and is sailing under the flag of United Kingdom.'

 

[Tranona]

?

'RAPSCALLION (MMSI: 232045880) is a Sailing Vessel that was built in 2013 (10 years ago) and is sailing under the flag of United Kingdom.'

You are correct. I was misreading and confusing it with the French charter boat that also had window failure.

The comment though remains that there is insufficient information to draw any conclusions about the insurance claim.

 

[Tranona]

I think that was Tranona's point above, the risk of it failing in action appears to be almost nothing or we'd be hearing about it regularly.

It's certainly a risk, and they do fail but it seems mostly when mechanical force is applied to a duff one which we hear about quite a bit. I don't imagine he was even arguing for the use of brass fittings, just saying that with proper maintenance they aren't the huge issue they're made out to be. I tend to agree but my boat does have TruDesign fittings so make of that what you will

Indeed. The issue is far more complicated because the potential weakness is not in the valve itself but in the fittings which are often made of plain brass which can dezincify in salt water. However even with advanced dezincification the component may still have sufficient strength and integrity to perform its primary function of connecting the valve to the hull and the hose to the pump or drain. Not so good though for withstanding any lateral stress such as hitting with a hammer. The photos in articles illustrating the consequences of dezincification almost always show crumbling threaded fittings discovered when dismantling through hulls or applying stress.

Using corrosion resistant materials such as DZR, bronze or non metallic composite eliminates dezincification so that they can stand stress tests as well as perform their normal design functions.

 

[awol]

This year, and with a degree of difficulty, I have pulled the shroud U-bolts from the deck to check for any crevice corrosion in the hidden parts. Apart from some very minor gelcoat damage I am happy to say that after a mere 41 years they are as good as new. I shall be rebedding the forehatch this winter, only 18 years after the last time 'cos a drip appeared while submarining (it is a CO32!). Ebersplutter exhaust hose will be checked and probably replaced - mine seems to get very brittle inside its lagging and cover. Yanmar exhaust bend will be checked ... and so it goes on with a whole series of winter checks though there is always some annoying niggle, usually towards the end of the summer, that I could have prevented with sufficient ESP.
I'm just glad I don't have to add hull windows to the list (or a fin keel!)..

 

[lustyd]

I'm just glad I don't have to add hull windows to the list (or a fin keel!)..

You don't have windows?

 

[Tranona]

This year, and with a degree of difficulty, I have pulled the shroud U-bolts from the deck to check for any crevice corrosion in the hidden parts. Apart from some very minor gelcoat damage I am happy to say that after a mere 41 years they are as good as new. I shall be rebedding the forehatch this winter, only 18 years after the last time 'cos a drip appeared while submarining (it is a CO32!). Ebersplutter exhaust hose will be checked and probably replaced - mine seems to get very brittle inside its lagging and cover. Yanmar exhaust bend will be checked ... and so it goes on with a whole series of winter checks though there is always some annoying niggle, usually towards the end of the summer, that I could have prevented with sufficient ESP.
I'm just glad I don't have to add hull windows to the list (or a fin keel!)..

Should keep you busy, although not sure why having hull windows would add to that list, nor a fin keel. Do you think that the hundreds of thousands of people who have fin keels and the tens of thousands that have hull windows lie awake at night worrying about them or dread all the extra work you suggest they might have to do in the winter?

Keep a sense of proportion. The fears that you and others seem to have are more in the mind than a reflection of reality.

 

[SaltyC]

I (and I'm sure many others) have the original build manual and details for my boat. It is invaluable in understanding what was installed, where and the exact parts used. But it really doesn't address the effects of ageing, especially on hidden parts or the construction details like adhesives or sealants used. Preventative inspection and maintenance is the right way to go and is well understood for rigging, chainplates, keel bolts, engines. The biggest difficulty is deciding how far to go with inspecting and replacing otherwise serviceable working items like masts, rudder shafts, electrics, windows, deck fittings.

Forums like this at least reveal potential problems and solutions. It is up to each owner to decide based on their use, boat age and type and at least in my case ability to repair. A lot of parallels with the risk assessment process used in safety and maintenance assessment.

My manuals give wiring diagrams, wire sizes, rigging sizes etc etc etc. The 3rd party supplied items ie engines, winches etc detail service intervals and requirements. However as Supertramp states, no indication as to service / replacement intervals for Hatches / windows etc. It is down to the owner and his understanding.

A lot of items, rigging, sails, engines etc should be assessed on a condition based maintenance system rather than just time. A 10 year old well maintained boat that has covered 5k miles needs rerigging???? Needs inspection and checking, yes. A 5 year old boat that has done 30K miles needs re rigging, Yes.

 

[awol]

Keep a sense of proportion. The fears that you and others seem to have are more in the mind than a reflection of reality.

I have no "fears" re hull windows just a morbid interest.

 

[Tranona]

I have no "fears" re hull windows just a morbid interest.

I can understand the interest - but "morbid"? What precisely is morbid about windows in the hull and more to the point can you explain precisely why, other than visual inspection and cleaning having them add to your winter list? Likewise with fin keels. Inspection and antifoul is all that is normally required although if iron there may be corrosion from time to time. However this is a consequence of the material not the keel design (says he who spent years battling corrosion on a bolted on long iron keel).

 

[justanothersailboat]

For keels there's a huge difference between this is my boat (and I know I never grounded, or grounded only gently) vs I bought this boat from people of doubtful responsibility (and I could have real problems if they hit a rock and pretended it never happened).

For hull windows (or any pure adhesive windows really) there's much less of that when in unaltered condition - unless a boat was thrashed really hard and flexed a lot, I suppose. Rare. It's more of an age problem; big glued-in hull windows are recent enough that most have not needed maintenance yet. When in as/near new condition I trust the engineers. When these boats are thirty years old or so, buying them will definitely add some stress. The odds are high I'll buy the one that some twerp stuck back together with bathroom silicone!

(and to the person who used bathroom silicone as stanchion adhesive in my current boat: pray that I never find you)

 

[awol]

I can understand the interest - but "morbid"? What precisely is morbid about windows in the hull and more to the point can you explain precisely why, other than visual inspection and cleaning having them add to your winter list? Likewise with fin keels. Inspection and antifoul is all that is normally required although if iron there may be corrosion from time to time. However this is a consequence of the material not the keel design (says he who spent years battling corrosion on a bolted on long iron keel).

"Morbid" as in schadensorge - as usual the Germans have a word (or several) for it. I have had friends whose insurance companies insisted on dropping keels ( 2 Bendytoys), I assume, just as with my U-bolts, because stainless steel in an anaerobic, possibly salt damp environment caused someone concern - is that "normal" maintenance? I wonder what insurance companies or paranoid owners are going to think up for hull windows.
Surely keel design must include the specification of material(s) not just the form?

 

[Pye_End]

When these boats are thirty years old or so, buying them will definitely add some stress.

Rapscallion is only 10.

Can you imagine, as a skipper, sailing in the middle of the ocean, going down below to find that level of water in the boat!

If I was an owner of similar then I would be seeking more information.

 

[Tranona]

"Morbid" as in schadensorge - as usual the Germans have a word (or several) for it. I have had friends whose insurance companies insisted on dropping keels ( 2 Bendytoys), I assume, just as with my U-bolts, because stainless steel in an anaerobic, possibly salt damp environment caused someone concern - is that "normal" maintenance? I wonder what insurance companies or paranoid owners are going to think up for hull windows.
Surely keel design must include the specification of material(s) not just the form?

You make an assumption that I would suggest is far from fact. There is no reason to drop a keel just because there is a possibility of corrosion of the keel bolts. The problem with your U bolts is nothing to do with stainless being "anaerobic" but is a well known phenomenon called crevice corrosion which occurs when stainless is in damp surroundings - and shroud plates and U bolts are classic examples where poor design and installation create these conditions - not helped with your design of boat by the U bolts (at least on the early boats) being underspecified. This rarely occurs in keel bolts in GRP boats simply because the conditions do not arise plus the fact that bolts have such a huge margin of safety that even severe corrosion, far worse than would ever occur as a result of crevice corrosion would be unlikely to cause failure.

This was of course different in the days of leaky wooden boats, and I have fine examples of such things in my garage from an old wooden boat of mine that one of my colleagues often used as examples in his lectures on the subject (he had a PhD based on his research into crevice corrosion).

Perhaps worth you reading my post#85 if you have not already done so. Your observations about two boats where the insurers required the keels to be dropped and the assumption you made is a fine example of how potential untruths enter the discourse. As you can imagine I come from a background that values both theoretical propositions but crucially hard evidence that either supports or challenges them. So theoretically crevice corrosion could arise in stainless keel bolts IF there was a failure in the seal between the keel and the hull. Given that the majority of modern fin keels are attached both with bolts and glued on the chances of water getting to the bolts without failure of the glue line are close to zero - and even if that did happen it would not be an insurance claim unless the failure was as the result of a collision or the boat falling out of slings.

So your example neither "proves" nor even "illustrates" any systemic problem with fin keels. All it does is show that the boats in question were involved in an incident such that the damage was sufficiently severe to warrant an insurance claim and for it to be considered prudent to drop the keel as part of the repairs. If you knew anything about the keel structures of modern boats you would know that most have an internal structure that can be damaged by grounding (which I suspect was the reason for the insurance claims) and repairs to this could well require the keel to be removed.

I could of course be wrong about these two boats and it would be really helpful if you could provide details of the circumstances, copy of the insurance claims and schedule of repair work

BTW Cast iron is almost universally used for ballast keels irrespective of shape or design (see post#110).

 

[Seven Spades]

It seems to me that these hull windows are an inherent design floor. Fibreglass hulls flex and shrink the windows will be stiffer and so when the hull flexes it is the sealant that takes the strain. The other issue is that the windows that are a "fancy shape" are going to be impossible to replace should the original manufacturer stop supplying spares which could mean the boat is written off.

I would be less concerned with the vertical windows in the aft cabins of boat like Oysters as there is less likely hood of flexing in that location and the boats are very stiff.

 

[lustyd]

I agree that the fancy shapes are a nightmare, although Jeanneau for instance do offer to sell the moulds once production stops. I disagree that they are inherently a design flaw, the adhesive sealant is designed for the job to be flexible and UV resistant. Also, whether "in the hull" or "in the coachroof" the windows are the same and the technology is the same. And regardless, we have one major failure, probably due to lack of maintenance, after decades of them being in use, and that didn't actually lead to any harm.

 

[doug748]

This has the makings of an issue similar to that of (brass) seacocks which complied with the relevant ISO standard for boat manufacture, but that in turn only specified a service life of 7 years (as I recall), even some top end builders were highlighted as using it as a vehicle for cost saving.... Quite a bit about that one in YM a few years ago.

Just showing your ignorance here, they might look like plumbing fittings, from up the Pound Shop, to you...

But to some they are a bold and imaginative use of new materials. ;- }

.

 

[Tranona]

Just showing your ignorance here, they might look like plumbing fittings, from up the Pound Shop, to you...

But to some they are a bold and imaginative use of new materials. ;- }

Yes, the widespread adoption of DZR brass (developed for the domestic plumbing industry) as a replacement for the traditional 60/40 brass and expensive bronze for seacocks and fittings in yachts was indeed a "bold and imaginative use of new materials".

 

[Stemar]

All I'm going to say on the subject of brass fittings is that part of my out of the water maintenance is a good welt on the through hulls and valves with a rubber mallet.



That wasn't even a welt with a mallet, just gentle pressure on a spanner
The handle came off in my hand when I tried, not very hard, to move it.

 

[Neeves]

Our catamaran had huge windows, apparently. They were secured with the same material as was used in the KL Petronas Twin Towers.

They did start to fail at just over 20 years, it was not the sealant/adhesive that failed - but the 10mm acrylic. Which developed single cracks from an outside edge.

We started to replace them.

This was one we had removed and you can see the enormous overlap used for the adhesive. There was never a danger, that we could imagine, where the windows themselves would detach.

This window we have removed and cleaned up ready to instal the new window. We replaced one window a day - the old adhesive was tenacious.

In terms of 'is it safe' it depends on the design, the huge overlap on ours - all adhesive, of an applied thickness to minimise thermal stresses, using 10mm acrylic - it lasted for over 20 years.

The worst conditions we endured was 8 hrs over 50 knots, beam seas breaking over the cabin roof. Yacht integrity was fine, crew were a bit apprehensive.

Large windows are not a risk if engineered and installed correctly.

When we decided to replace I spoke to the adhesive manufacturer and they spent about 1 hr on the phone with me. They then sent a double page instruction carefully outline each stage of the replacement, coating thickness, temperatures (we installed late in the afternoon to enjoy the cool of evening to set off slowly. We used about one tube of sealant for each window.