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Old 28-08-2020, 12:51   #16
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Re: Seacock & thruhull replacement

Yep the leopard 40 has 11

2 x aircon
2 x head
2 x engine
1 x generator
1 x generator out under waterline
1 x Watermakers
1 x depthsounder And wheel
1 x raw water Wash down

Seems someone might design a central chamber that runs in the hull up a bit higher than the waterline that all hoses would draw water from in one place removing the need and threat of multiple strainers and thru hulls failing. Sort of like an inverse bilge

But Iím no marine engineer

Anyway...any ideas on Marelon vs trudesign vs brass and bronze longevity?
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Old 28-08-2020, 13:58   #17
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Re: Seacock & thruhull replacement

These look like Groco bronze fittings. They do not look bad imho.


However the way they are fitted look unusual. I mean that square thing below the fitting - is it a grp padding block or something?


I never hire boatyard to replace them. I just remove the one I do not want and replace with a new one. To me it seems an easy job as long as there are good tools at hand (and a helper to be on the opposite side of the hull ...



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Old 28-08-2020, 15:02   #18
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Re: Seacock & thruhull replacement

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Originally Posted by Snowgoose71 View Post
So thinking of replacing seacocks on my 1998 Oceanis 352. Would like to hear from others:

1. I assume the thruhulls should also be replaced at the same time?

2. Is this something the boatyard should do? And if so, about how much should I plan to do 7 seacocks (and thruhulls?).
- 1. Not necessarily considering these are bronze, unless if you want to go with composite seacocks as these need to have a complete system. After removing the seacocks thoroughly clean the thruhulls and make sure you see not color change (usually pink) telling you there is a material disintegration. Use this time to make the best possible inspection also for any leaks, hull cracks etc. inside and out.

- 2. Quite easy to replace the seacocks only, but follow the instructions, see some YouTube etc. You may want to upgrade also the tubing and clamps at this time.

Any boatyard can remove the thruhulls for you. If only the 7 without any extra work, it shouldnít take more than 2-3 hours, considering that the fittings are not glassed or glued inside the hull.
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Old 28-08-2020, 16:32   #19
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Re: Seacock & thruhull replacement

Hi. First, please look up sea chest. Itís a box, one big seacock then big strainer in, multiple valves out. Watermakers sometimes need a seperate seacock /strainer Same, main engine.
Next, you are going to get lots of opinions. Please sea about me as Iím a professional builder with 50+ years.
Forespar Marelon . Worst mistake I made ever. Iím taking all of them out and replacing them with Groco adaptor plates and ball valves 316 because itís an aluminum yacht. Groco and Apollo make fine bronze seacocks and thruhulls.
There is a post on marinehowto that will show you how.
Supported valves. Tru Design,Forespar, and others
Supported valves are not bolted to the hull or a backing plate welded or epoxied to the hull. What hold the assembly together is the thruhull. I do not consider them seacocks because of this fact. Please listen to why.
Every year there is a big boatbuilders show called IBEX where people try to get boatbuilders to buy the latest stuff. Real bronze seacocks and thruhull are expensive and last a very long time. The buzz word is cheap and requires a new and better in a few years...not seaworthy...cheap, light, fast to install.
The 500 lb static test ? Exactly. Static. The industry test. Boats are not aircraft.
So take a sledge hammer to a valve that is not bolted to the hull and youíll see exactly why I only use 316 Stainless or silicon bronze.
Now Iíll wait for comments from those who know more than me because they have worked for more OEM companies and they can show you all the boats they have built with their own hands.
Expertise is gained by experience not dock bar talk or the number of posts or a blog which details what your cat did yesterday.
It will be expensive to buy bronze thru hulls. It will take time to research how to put them in. It will take a lot of labor. In the end you can be proud of your work and when you go to sea, you will know you are seaworthy.
Happy trails to you.
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Old 28-08-2020, 17:44   #20
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Re: Seacock & thruhull replacement

If you have the yard do it, they will have a worker and a helper do the work as someone usually has to be on the outside to hold the fitting to keep from spinning. They will need to prep, remove whatever hose is attached, uninstall, and reinstall new with bedding, then reattach hoses. Depending on access, probably looking at around 45-mins per thru hull barring anything difficult. Around 5-6 hours for 7, or 10-12 man hours. Most US boat yards are in the $100+/hr range so somewhere between $1000 and $1500 for all seven, plus hardware and materials.

Bronze seacocks are incredibly strong and last a very long time. Not unusual for them to last 30+ years with minimal maintenance.

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Old 28-08-2020, 19:10   #21
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Re: Seacock & thruhull replacement

In 2005 I replaced the thru hulls and valves on my 1985 Beneteau in Marmaris.. They were bronze, but I felt 20 years was enough. I asked the boatyard if they had bronze replacements, and they said I'd better bring them from the USA. Removing them was easy with a right angle grinder to grind off the outside flange. Replaced with Greco thru hulls and Apolloi valves. The yard gave me a helper for the installation, and he brought some.really good loctite goop to seal the bsp thru hull to the npt valve threads. Never leaked a drop in the 8 years I kept the boat, and is probably still goo today.
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Old 28-08-2020, 19:57   #22
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Re: Seacock & thruhull replacement

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Originally Posted by cat-keys View Post
Yep the leopard 40 has 11

Anyway...any ideas on Marelon vs trudesign vs brass and bronze longevity?
Marelon valves seize up erratically and then work ok. No idea why but the manufacturer requires frequent operation and some lubrication.

Bronze valves can look fine and then break off because they have degraded internally. Caused by tiny currents in the wrong place.

Trudesign composite valves can be left in one position for years and not stick. They will never be affected by those tiny currents.

Will they take a sledge hammer blow? Dunno, I've never tried and don't have a sledge hammer on board. However, they have a support collar that ensures they are strong enough to take the hardest hit they are ever likely to.

I just know I feel a whole lot safer with no metal valves to break down and no marelon to seize up unexpectedly. Both have happened to me.

All this from a sample size of one. Just like all the other opinions here.
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Old 28-08-2020, 20:03   #23
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Re: Seacock & thruhull replacement

[QUOTE=donradcliffe;3219515. Replaced with Greco thru hulls and Apolloi valves. The yard gave me a helper for the installation, and he brought some.really good loctite goop to seal the bsp thru hull to the npt valve threads. Never leaked a drop in the 8 years I kept the boat, and is probably still goo today.[/QUOTE]

BSP to NPT? Now that's just plain stupid.
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Old 29-08-2020, 02:58   #24
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Re: Seacock & thruhull replacement

Quote:
Originally Posted by DeValency View Post
- 1. Not necessarily considering these are bronze, unless if you want to go with composite seacocks as these need to have a complete system. After removing the seacocks thoroughly clean the thruhulls and make sure you see not color change (usually pink) telling you there is a material disintegration. . .

That is the approach that I took, on advice from a surveyor I respect a lot. I cleaned with wire brush then did a little filing to inspect the metal below the surface. Mine are 19 years old and were declared fit for further service. Good 85-5-5-5 bronze skin fittings made by Maestrini in Italy. The surveyor said that in the absence of any electrical funny business, these should last for decades more.



Quote:
Originally Posted by DeValency View Post
. . .Any boatyard can remove the thruhulls for you. If only the 7 without any extra work, it shouldnít take more than 2-3 hours, considering that the fittings are not glassed or glued inside the hull.

Caution -- this can vary a LOT. If they are easily accessible and there are no special problems, then 2 hours for 7 skin fittings is possible (is this remove, or remove & replace?). But with complications this can easily turn into a full day job.



Even R&R of ball valves can be time consuming. There are a number of things which can go wrong . . . .



Don't ask me how I know . . . .
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Old 29-08-2020, 06:20   #25
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Re: Seacock & thruhull replacement

Hi. Please read post 7 by Captain J. and watch the proper way to do seacocks.
One of the most common mistakes is confusing threads because this can be very dangerous. Straight thread should never be inserted into tapered fittings. You can sometimes get a few threads together but there is no real support and the application of some type of sealant is just going to hide a problem. They are not designed to go together...period.
Here is how to tell the difference.
Thruhulls are usually straight thread. You have a nut which screws along the thread like a nut and bolt. Lay two rulers or a flat surface and a ruler along the threads opposit one another. You will see the edges are parallel.
Now take a pipe nipple and do the same. You can see the edges converging or tapering. In female tapered fittings, itís a little more difficult to see, but itís there. Tapered fittings are designed to lock together to prevent leaks.
Application. Groco adaptor plates have both. The female side is straight thread.
This faces the ocean and is designed to take a thru hull with straight threads.
The male inside is tapered so you can use any ball valve or pipe fitting with the usual tapered threads.
Real seacocks...seacocks that are attached to the hull...will have straight threads for the thruhull and tapered for fittings inside the boat.
Lastly, I have examined hundreds of seacocks. I recently looked at all the Apollo bronze seacocks which were in a boat I built 40 years ago and they looked and worked perfectly. I have never seen a real bronze seacock corrode unless it was bonded to an electrical system with real problems. In this one case, the corrosion was limited to the stem bolt and handle.
Tru Design, Forespar and other supported valves rely on the integrity of the thruhull. If the exterior head of the thruhull is damaged by an object, ice or a reef the valve will loose this integrity. You will wish it snaps off cleanly so you can plug the hole. If itís just loose, itís vey difficult to stop the water.
With a proper seacock, you can remove the thruhull, grind off the mushroom head and it will still keep the sea out.
Supported valves are cheap to buy and fast to install. Well till later...
Happy trails to you.
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Old 29-08-2020, 09:40   #26
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Re: Seacock & thruhull replacement

Actually Trusign thru hulls are epoxied into the hull and become part of it. If you hit and chipped off a piece of the mushroom you would not cause a leak.
Mine are flush and not far forward so I don't think there is much of a chance of hitting them.
If one did get damaged I would just cut it out with a hole saw and epoxy in a new one.
I would worry more about the speed transducer taking a hit.
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Old 29-08-2020, 10:45   #27
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Re: Seacock & thruhull replacement

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Actually Trusign thru hulls are epoxied into the hull and become part of it. If you hit and chipped off a piece of the mushroom you would not cause a leak.
Mine are flush and not far forward so I don't think there is much of a chance of hitting them.
If one did get damaged I would just cut it out with a hole saw and epoxy in a new one.
I would worry more about the speed transducer taking a hit.
+1! With my Trudesign skin fittings. Used 5200 out, in and between the 50mm cored hull after epoxying the clean hole between the inner and outer glass skins (5mm each) into the balsa core.
Wouldnít expect removal before scraping the hull - probably in 100 years...
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Old 29-08-2020, 13:35   #28
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Re: Seacock & thruhull replacement

Hi. I stand corrected. With a balsa cored hull installing a bronze seacock would necessitate removal of the core in a substantial area and the application glass and epoxy in multiple layers thus creating a hard spot which might lead to fracture of the outer skin or delamination and water intrusion into the surrounding core.
In lightly built boats, true race captains would be appalled by the weight of bronze seacocks.
It would be like having a manatee for a crew and tossing them over after the finish line while proclaiming to the race committee...manatee...what manatee.
Happy trails to you.
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Old 07-09-2020, 07:12   #29
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Re: Seacock & thruhull replacement

We have 17 below waterline thru-hulls (yikes! and this was after decommissioning 2 unneeded ones). Replaced them all with Trudesign skin fittings, valves and collars 4 years ago and have been very happy with the results. No corrosion, no stuck valves, no issues. Easy enough DIY job as long as you take your time and do it right. Hardest part is getting the old stuff out and cleaning up the holes.
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Old 07-09-2020, 08:26   #30
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Re: Seacock & thruhull replacement

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