Forspar Marelon Valves in engine room ? Any surveyors can help ?

[zambant]

I am shortly replacing all my through hull fittings and valves below the waterline for Marelon plastic units.

I have my raw water intake in the engine compartment and I suspect that my insurance company would not approve if I replaced the existing bronze unit for Marelon in the engine compartment.

Any surveyors out there or experts can help please?

Thanks

 

[NormanS]

I'm no expert, but that is exactly what I have. Insurance surveyor had no worries about them, and neither do I.

 

[TradewindSailor]

Marelon should be fine. I don't know what the RCD says about it when used in the engine space, but if it gets hot enough to damage the valve, I think I'd prefer to have a water leak.
My local chandler over here in NZ doesn't stock any metal seacocks now.

 

[VicS]

Some people have plastic bodied water strainers in the engine compartment.

 

[David2452]

I recall seeing a youtube video with an oxy torch played on one for quite a while and it retained its integrity and self extinguished, even still worked on and off. I can't seem to find it again to provide a link but I definitely didn't dream it.

 

[TradewindSailor]

Some people have plastic bodied water strainers in the engine compartment.

I don't see why you're making a fuss. The hoses are rubber, and yes most strainers are plastic and above the waterline.

If you have a fire in the engine space that isn't put out may the automatic fire extinguishers, you're probably better off flooding the engine space .... quickly.

 

[Bosun Higgs]

I suspect that my insurance company would not approve if I replaced the existing bronze unit for Marelon in the engine compartment.

Why do you think that? After all they approve of a plastic hull. And of brass seacocks as used by BenJenBav. And of your existing no doubt plastic fittings for the loag and depth sounder.

 

[Tranona]

I am shortly replacing all my through hull fittings and valves below the waterline for Marelon plastic units.

I have my raw water intake in the engine compartment and I suspect that my insurance company would not approve if I replaced the existing bronze unit for Marelon in the engine compartment.

Any surveyors out there or experts can help please?

Thanks

Would probably not be accepted if the boat is coded. Not sure there is a reliable technical reason, but the argument is that a metal seacock does allow the water supply to be turned off if the water hoses, which are usually plastic get damaged by heat.

Not sure why you want to use that type of valve anyway if you have a GRP boat. The main advantage of them is only really of value with a steel or aluminium boat as it is not necessary to isolate them from the hull material. They operate the same way as a metal cased valve and have the same requirements to operate regularly to avoid sticking. However, they are physically bigger for the same bore size and do not have the same range of downstream fitting options. They are also more expensive in the UK and not so readily available.

They have been on offer for many years in the UK but have never made much impact on the market as good quality DZR fittings are readily available and perform well in practice. The lack of market acceptance here may also affect some surveyor's views about their suitability in engine rooms.

 

[timmygobang]

I don't see why you're making a fuss. The hoses are rubber, and yes most strainers are plastic and above the waterline.

If you have a fire in the engine space that isn't put out may the automatic fire extinguishers, you're probably better off flooding the engine space .... quickly.

I totally agree, and went for Marleon seacocks based on this theory. If you're worried about the seacocks being plastic you should probably change all the plastic hosing to solid metal...

Yes they're more expensive, but I read on another post today that someone had 5 year old DZR's and were worried about corrosion, not an issue with plastic seacocks.

You should watch this btw
http://www.youtube.com/watch?v=fTImxBOPbyI

I'm sure plastic technology has advanced sufficiently, so I've moved out of the bronze age

 

[timmygobang]

not so readily available.
.

Bought mine from Force4 no issues, took a week to order in.

 

[Tranona]

Yes they're more expensive, but I read on another post today that someone had 5 year old DZR's and were worried about corrosion, not an issue with plastic seacocks.

If they were DZR then it is unlikely there is anything to worry about in respect of corrosion.

The panic over corrosion in metal valves is because some builders have been using brass which can suffer from dezincification. DZR means dezincification resistant and as the name implies do not suffer from corrosion so entirely suitable for underwater use.

So provided you buy DZR from a reputable supplier there is no need to pay extra money for a product that has no advantages. If you had a steel or aluminium boat you might make a different decision as I explained earlier, although many people use DZR or Bronze as there are various construction techniques available to isolate the valves from the hull.

 

[zambant]

My valves are showing definite signs of pink metal and green corrosion around them so time for ones below or on the water line to be changed

 

[Tranona]

My valves are showing definite signs of pink metal and green corrosion around them so time for ones below or on the water line to be changed

The green is quite normal. If they really have dezincified, then they are probably brass. Change them to DZR. Straight replacement. Make sure they are not connected to any other metal.

 

[charles_reed]

Would probably not be accepted if the boat is coded. Not sure there is a reliable technical reason, but the argument is that a metal seacock does allow the water supply to be turned off if the water hoses, which are usually plastic get damaged by heat.

Not sure why you want to use that type of valve anyway if you have a GRP boat. The main advantage of them is only really of value with a steel or aluminium boat as it is not necessary to isolate them from the hull material. They operate the same way as a metal cased valve and have the same requirements to operate regularly to avoid sticking. However, they are physically bigger for the same bore size and do not have the same range of downstream fitting options. They are also more expensive in the UK and not so readily available.

They have been on offer for many years in the UK but have never made much impact on the market as good quality DZR fittings are readily available and perform well in practice. The lack of market acceptance here may also affect some surveyor's views about their suitability in engine rooms.

Suggest you get up to speed on the up-to-date plastic seacocks - several inaccuracies in your comments.

 

[Tranona]

Suggest you get up to speed on the up-to-date plastic seacocks - several inaccuracies in your comments.

Please explain the inaccuracies. Don't understand the "several" where I have made two observations. First they are physically larger and second they don't have the same range of downstream fittings. Which of these is inaccurate? Many thanks.

 

[fishermantwo]

The green is quite normal. If they really have dezincified, then they are probably brass. Change them to DZR. Straight replacement. Make sure they are not connected to any other metal.

Bronze will de zinc as well. Mate lost a blade off a two bladed propeller recently. In the remaining prop there was only a cross section of real bronze about 5mm across. The rest was like pink cheese.

 

[Tranona]

Bronze will de zinc as well. Mate lost a blade off a two bladed propeller recently. In the remaining prop there was only a cross section of real bronze about 5mm across. The rest was like pink cheese.

That is galvanic corrosion, probably because it is in contact with other metal - likely stainless steel. You do not say what the "bronze" is - often manganese bronze for props, which is a brass. This does not occur with a DZR or bronze seacock or fittings in a GRP hull. There is no other metal (assuming non metallic hoses). Brass will dezincify in contact with sea water because it is copper and zinc. DZR and bronze will not.

 

[charles_reed]

Please explain the inaccuracies. Don't understand the "several" where I have made two observations. First they are physically larger and second they don't have the same range of downstream fittings. Which of these is inaccurate? Many thanks.

I've just changed the, admittedly brass, toilet seacock for a glass-reinforced plastic one. It weighs 20% of the old one and has a 20-year warranty. It's made in NZ. So called DZR (of which the tail was made) was definitely de-zincified after 22 years.
Blakes valves are unobtainable in Greece, 316 stainless ones are available (at €75), the plastic one cost €68. The comparable Blake's unit from ASAP supplies is £158, and as far as I know has no lifetime guarantee.
Case rests.

 

[machone]

Renovating my Steel boat I've just bought the Forespar Marelon valves to replace the bronze 40 year old valves. Whether the corrosion was galvanic or not I don't know, but the most significant areas of steel hull thinning were around the skin fittings. This was my main reason for going with plastic. The bronze valves were the same fitted by my father over 40 years ago and as far as I know performed flawlessly all that time. Certainly we have had no problems with them since buying the boat a couple of years ago.

One worry I have about the forespar fittings is that the recommended method is to fit direct without gasket, using sealant! Is there a sealant suitable for an engine room? The valves have a webbed/meshed underside which fills with sealant and seems to me the worst design for a watertight seal. Fitting is a two person job as the valve itself screws into the fitting. Anybody any recommendations on gaskets or not?

 

[charles_reed]

Renovating my Steel boat I've just bought the Forespar Marelon valves to replace the bronze 40 year old valves. Whether the corrosion was galvanic or not I don't know, but the most significant areas of steel hull thinning were around the skin fittings. This was my main reason for going with plastic. The bronze valves were the same fitted by my father over 40 years ago and as far as I know performed flawlessly all that time. Certainly we have had no problems with them since buying the boat a couple of years ago.

One worry I have about the forespar fittings is that the recommended method is to fit direct without gasket, using sealant! Is there a sealant suitable for an engine room? The valves have a webbed/meshed underside which fills with sealant and seems to me the worst design for a watertight seal. Fitting is a two person job as the valve itself screws into the fitting. Anybody any recommendations on gaskets or not?

The ones I bought were not Marelon (which is, I suspect, a trade name to justify an increased margin) - they had no facing serrations and I used teflon tape on the male thread. They are made in New Zealand under the trade name "Tridesign". From reports DZR seacocks are no longer available in New Zealand - that may be because there is a flourishing boatbuilding industry in aluminium (unlike the UK) and aluminium and bronze just don't mix.
Though many suppliers claim their fittings are in bronze, I have to confess to a hefty dose of scepticism, especially as the major French boatbuilders appear to have standardised on brass. I have to infer, from that, that bronze fittings just aren't being made, rather than the boatbuilders are being irresponsible!!!