[70521]
Well-Known Member
Gosh, all my sea cocks are located in areas where fat knacker crew can't fall on it or drop a scuba tank on it.
New sea cock time.. stainless, dzr or Marelon?
- Thread starter contessaman
- Start date
dankilb
Well-Known Member
Think this is the key point re: requirements specific to the type of vessel. I was thinking the same - on our AWB all seacocks are in cabinets under sinks or behind/beside heads ‘bowls’, etc. If there are heavyset crew members or heavy gear flying around in these areas, we’ve probably got bigger problems than bronze vs composite!
I notice that Mads of SailLife fame recently fitted a Groco under his holding tank (having used TruDesign elsewhere) in case the tank should ever fall on the fitting.
We even went as far as to relocate our engine raw water intake so as to reduce the risk of it being trodden or dropped on. It also has a load bearing collar, whereas those in well-protected cupboards/corners under sinks etc. didn’t get this addition.
vyv_cox
Well-Known Member
My Blakes seacocks date from 1984. Blakes themselves do not know exactly when their production changed from bronze to DZR but it was about that date. The colour of mine suggests to me that they are likely to be DZR. At 35 years old they are still in good condition. Slight pitting on the cone surface but otherwise almost like new.
Zing
Well-Known Member
I disagree with him in part. It is correct that brass balls (zinc coated by the way usually) are not a good choice, but it is not true about affordability. In actual fact you get affordable bronze valves with bronze balls. Apollo make them amongst others.
Zing
Well-Known Member
Another example for you to consider. You bash a log in the water. It hits directly your precious plastic though hull. Will it collapse inwards and will a bronze one be much more likely to hold up OK?
contessaman
Well-Known Member
Great replies thanks everyone. Im sold on the trudesign ones and I can get them from force 4. Would you recommend using the true design skin fittings with the valves or dzr skin fittings with trudesign valves? I totally done have a problem with space around the valves on my boat.
also, I’ve got some underwater lights fitted years ago a kiwi brand and they are plastic trough hulls as are my ray marine and echo pilot transducers so I’m not buying the everything below the WL has to be bronze argument.
cheers for all replies
also, I’ve got some underwater lights fitted years ago a kiwi brand and they are plastic trough hulls as are my ray marine and echo pilot transducers so I’m not buying the everything below the WL has to be bronze argument.
cheers for all replies
contessaman
Well-Known Member
All the people saying plastic is not suitable, I presume you dont have plastic through hulls for speed or depth transducers?
Elessar
Well-Known Member
Probably not.
And it’s an unlikely failure in the event of what itself is an unlikely scenario whilst corrosion is inevitable (albeit slow if you KNOW the quality of the metal).
What’s more in the collision you describe you will hammer the wooden bung you have shock corded to the hose into the hole.
When the corroded fitting fails you are more likely to be at home and you lose your yacht.
All in all I think plastic has the edge.
vyv_cox
Well-Known Member
Totally different material. The plastic used for transducers is a
Chromium plated most commonly but some more expensive ones are electroless nickel plated.
USA imported valves may have bronze balls, I cannot see whether Apollo state this or not. But they are not an item that most yachtsmen have ready access to without specialist knowledge. And considerably more expensive than DZR
[70521]
Well-Known Member
Lets work this out.
Lets say the log's diameter is 25 cm and only 25% is above the water and is drifting with the tide.
All my through hulls are under the engine, the galley area or exiting the heads towards the transom. Nothing is anywhere near the waterline. I consider the risk minimal. Each thru hull has a backing plate that is additional protection.
Graham376
Well-Known Member
Trudesign are are lot stronger the a de-zinced skin fitting. They are made out of composite in a composite hull in most cases, unlike the flimsy plastic injection moulded skin fittings for the depth and log which may well have been knocked off by the log. .
vas
Well-Known Member
That's clearly science fiction territory even for a 20kn mobo, let alone a 6 or 8kn sailing yacht. Would be interested in reading a material scientists take followed by a structural engineer's one on this highly unlikely scenario.
I think you made it V clear that bronze is for you, fine by me especially if you're absolutely definitely sure that's what you bought. That was my reasoning for going trudesign in Greece, nobody really knew what they were selling!
Otoh, trying to find obscure reasons why plastic is crap is pushing it IMHO.
Never heard of any boat sinking on its mooring unattended due to grp skin fittings, cannot say the same for metallic ones. Even the marelon handle breaking off won't happen by itself!
Cheers
V
Zing
Well-Known Member
Probably because 1% of boats have plastic skin fittings, and one in 100,000 boats sinks in its slip, so that is a small needle in a big hay stack you are looking for. Look for the broken one first.
LONG_KEELER
Well-Known Member
I think there is more of a risk with plastic transducers being damaged in travel lifts etc rather than when sailing.
A power boat going fast might be an exception.
A power boat going fast might be an exception.
Zing
Well-Known Member
Half my through-hulls are near the water line. Hitting a log was just an example. Pretty common in the Pacific North West by the way. Also you could hit other things. In the UK, a semi submerged pram may be your object of choice. Or try bumping into a rock even.
RJJ
Well-Known Member
And there's enough people looking at this topic globally that if there was a failure...given Marelon have been around for well over a decade (correct me if I'm wrong), and TruDesign not far behind...and I'm going to say 1% is massively under-egging it...I figure we'd know about it by now.
The US design authority for sailboats has a specification for seacocks. TruDesign passes it, easily. Nobody's told us of any incidents. There are loads of incidents with people thinking they had bronze/DZR, when in fact they had brass. I figured the state of my skin fittings and hose tails was a near-miss when I replaced them all this year; bright pink inside.
It's not clear why you're objecting to Trudesign. The skin fitting is as strong as the hull it sits in; your imaginary log or rock, is I reckon more likely to make a hole in the hull itself than poke the skin fitting through.
RJJ
Well-Known Member
I don't reckon your boat manufacturer specifies a lifespan of the fibreglass they sell you either, and for the same reason.
Pye_End
Well-Known Member
This would be somewhat surprising when the hull is multiple times thicker.
Skin fittings that are proud of the hull are a bit exposed if hitting a foreign object that slides down the hull - the flange is probably at most risk. Decent well cared for bronze skin fittings are no doubt stronger than plastic alternatives. The points about risk, and of de-zincification are also well made.
Presumably the OP was asking about the valve fitting rather than the skin fitting - can't see any reason why a plastic valve can't be used on a DZR skin fitting? Good to see the arguments both sides - easier to make an informed choice.
WRT transducers - my DST800 said not to use a plastic skin fitting with a fairing block, but to go for a bronze one instead. Greater exposure and risk of getting hit, damaged perhaps the reason for this manufacturer's advice?
Zing
Well-Known Member
No the plastic fitting is not remotely as strong as the hull. Why anyone would choose cheese to make a product from when they could choose kryptonite defeats me. Enjoy your cheese. I’m tired of debating with mules. I’m outa here.
Graham376
Well-Known Member
If you read the instructions for Trudesign, they suggest epoxying into the hull as one method so, it becomes in effect part of the hull.