Marine product, do not get wet.

[Mirelle]

Douglas Gill bags

I find we have three in the family. The oldest, and much the best in terms of quality, is green, yellow and blue, and apart from sailing has done duty as my suitcase all over the world. Plastic zips. The other two are dark blue and red and seem not to be as robust - made of thinner stuff - but also plastic zips.

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[kimhollamby]

Understood

I guess this simply comes down to varied experiences.

Have had metal silencers rot out and dump loads of water in bilge but no disasters with poly silencers. Have had several overheats with other types of strainer but none with the Vetus type. Personally comfortable with them but very much understand anyone who has had problems would feel differently.

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[Evadne]

I am always annoyed that so-called marine equipment doesn't have a suitable IP rating. These have been around for years and only IP67 and IP68 do not permit any ingress of water. Even IP66, which is nominally for use on the deck of a ship, allows "limited ingress". Any lesser rating or worse still, no rating at all, means that it ain't waterproof. Caveat vendor I suppose.

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[SlowlyButSurely]

Re: Flip side

What's wrong with polyprop exhaust fittings?!!

Anyone who has been down the French canals will tell you that there are stretches which are completely covered with duck weed. The banks on these stretches are littered with melted Vetus waterlocks.

It's hard to think of a more pathetic reason for engine failure! Isn't it?

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[kimhollamby]

Genuine interest

Is it the case that the polyprop gives up before the exhaust hose? Genuinely interested to learn as haven't experienced one of these failures personally and would like some more info...the boats I have used polyprop silencers on have had a long run of hose between exhaust elbow and silencer and they have also had exhaust alarms, so overheats have never got critical, fortunately.



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[ParaHandy]

Re: Genuine interest

Polyprop (assumed to be homo-polymer) will distort rapidly above 120 degrees C which does make it an unusual choice of material for an exhaust. An engine with heat exchanger (most yachts) might continue running for some time after the sea water stopped circulating which could allow the exhaust temperature to rise well above 120 degrees C before the engine over-temperature alarm sounds and assumes you don't have an exhaust alarm.

Length of hose might not help as the hose is unlikely to dissipate a worthwhile amount of heat.

PP will become very brittle around 0 degrees C although that might be a safer bet as it's a few years since the sea froze over ...

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[pugwash]

Re: Litigation

You make some fair points, Kim. It's not a question of journalists being "in the pockets" of advertisers but sometimes of being so wary of them that important things are just sidestepped. Can hardly blame you, in one sense, but it works both ways. If you accept advertisements for kit that costs your trusting readers good money and it turns out to be dud, aren't you equally (morally if not legally) obliged either to say so, or to refuse to print the advert? I suppose readers do have recourse to the ASA, but that shouldn't be necessary.

Years ago I wrote for a big motoring magazine that got an independent outfit (I think the BSI) to test in-car fire extinguishers. We were honest and fair in our appraisals but one just didn't work and we said so. The company boss threatened all sorts of mayhem and we agreed to test his product again as long as we could buy the thing anywhere we chose and could print the result. He agreed. We tested again, it didn't work and we said so. One morning soon afterwards there was a big noise in reception as the company boss pushed past various bods, charged into the editor's office and pointed a fire extinguisher at him. "I'll show you my extinguishers work!" he yelled, and pulled the trigger. It didn't work.

Those were the days !


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[Mirelle]

YES!!!

Having melted three Vetus waterlocks this season, I can confirm that the waterlock "goes" long before the exhaust hose and indeed before the pump impeller.

My boat has a conventional exhaust injection bend followed by about one foot of hose before the waterlock, then another 12 feet of hose to the outlet. This length includes a loop up under the deck. The temperature at the bottom of the steel injection bend, in normal operation, is hand hot, no more, and this is within inches of the water injection point.

Failure of the waterlock is almost immediate upon failure of the water supply.

Where the cause of the failure of the water supply is due to air entering the system at the (Vetus) strainer cover, one may well curse the name of Vetus!

I have now followed the advice of several people and relocated the strainer well below the w/l, contrary to the Vetus installation diagram, arguing that a drip into the bilge is of no consequence, but air in the cooling circuit is something I know too much about altogether.

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[MainlySteam]

Re: Genuine interest

I do not know if the material is actually polypropylene or some other injection molded plastic, but isn't it a case of you get what you pay for. I also note that Vetus recommend that a VETUS exhaust temperature alarm is always installed in the exhaust line.

The alternative is to pay for more expensive fire resistant fibreglass components such as those Centek manufacture. In that case an exhaust temperature alarm is probably unnecessary on a yacht auxiliary as long as one is alert to the change to a hollow exhaust note when a "wet" exhaust is dry, or have a visible water flow tell tale that is visible from the watch position.

The choice is the consumers.

John

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[Gunfleet]

Re: Understood

I wonder why boats can't have stainless silencers. Cars can. FWIW I overheated my engine recently (turned the seacock off to check for weed before I started, then forgot to turn it on again... oops). My 1ftx45mm reinforced rubber hose distorted and became useless, but the Vetus silencer was fine, so in my case it was definitely hose fails before silencer.

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[MainlySteam]

Re: Understood

<<<I wonder why boats can't have stainless silencers.>>>

They can and do, but as long as they are in dry exhausts. Chlorides drying onto stainless steel from wetting and drying cycles result in stress corrosion failure. For the same reason, stainless steel is not that great even for storing hot fresh water in process plants, etc (saw an about 50 foot high by 30 odd foot diameter one that had just fallen over with close to boiling water in it - fortunately there was no one around when it failed).

John

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[Gunfleet]

Re: Understood

Ah. I see. BTW don't you ever sleep?

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[MainlySteam]

Re: Understood

Re the sleep. At the moment most of my clients are in much different time zones - they don't seem to think I should have regular sleeping hours, so I have given up worrying about when I sleep!

On the stainless steel muffler question, what usually happens with wet exhausts on bigger vessels is that a stainless steel muffler is used but the exhaust is dry from the engine to the muffler exit and the spray ring injecting the seawater cooling water is placed after the muffler. The wet exhaust is then carried in a welded ss pipe to the discharge from the boat but the pipe doesn't seem to suffer the same stress problems as a fabricated light gauge component such as a muffler which doesn't drain.

Regards

John

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[Peppermint]

Re:Not just boaty problem

Though the times I've seen yachts with electrical failure because of damp. As I think of it my Musto sailing knife rusted into it's scabbard in a season too.

Anyway, the current wife spent a fortune in our bathroom. The bath panel and loo seat cost nearly £500, god the things I say yes to to get some sailing in, and were made in a limed wood finish. These were not Micky Mouse items they were from a leading bathroom fitting company. We gave up after the third set had warped and shed it's paint. The company suggested that we should know better than to get them wet "as it's impossible to make wood waterproof by coating it" This will come as a surprise to those who, like I did at the time, own a wooden boat.

You might ask why you'd continue to sell a bathroom product that couldn't take a bit of damp. Clearly they should get into boat equipment sales ASAP.

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[roger]

hose limitations

Bought a garden hose once. The instructions said all the water must be emptied out after use!!

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