Ball valve change out

boatpoker said:

If it's just grabbing the first 2-3 threads then you have n NPS throughull on an NPT ball valve....... not a good thing !

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Agree w/ boatpoker...

Previous post deleted - Thanks for the correction psneeld - I didn't realize these were adapter flanges I thought these also had NPS threads

Holy cow... ....the flanges are straight threads to work just fine with the thru-hull.....

it's the ball valves that are screwed up when trying to screw on to a straight thread thru-hull...thus the flanges and their straight threads for the thru-hull but tapered for the ball valve on top.

Limit your input here and go back to the install instructions...not everyone is familiar with these flanges and even if they are...I don't even trust some of the things I post...in a rush, one too many wines, boss calling to send me out in crappy weather but trying to help....

For all the hand wringing...you can't find a short haul place for an hour or two for $150 bucks or so? Wait for the next bottom cleaning and do a pressure wash to?

Yeah. I think I will haul it. Especially since I'm installing the flange now. Getting a little more complicated-- looks like I need to take the backing nut off the thru hull before I install the flange adaptor. More stuff that can go wrong. Guess while at it I will install those threaded backing plates and use some 5200 to glue them down. Make it look all official.

I really wanted to try out my Red Thingy but I guess that will have to wait for a real emergency. ?

Unless you need access under the hull, maybe the yard will allow you to replace the whole kit and caboodle while hanging in the slings at the haulout slip for a discounted price. This way you're out of the water temporarily while the job gets done without flooding risk. But if things go wrong, they can complete the haulout to allow you to correct the situation in the yard on your own.

Glad to hear you've rethought doing this in the water.

Me too!

I feel much better now , thank you . I can put my nitroglycerin pills back in my pocket .

This thread has gotten a little wacky. Some observations:


1. Niether the hat shaped plug or the stepped wrench that holds the thru hull can be used from the inside or at least not with the valve corroded closed.


2. That existing ball valve is probably a tapered NPT thread and since it is screwed onto a straight NPS thread, that is why it is only catching a few threads. Not good.


Study these photo essays of thru hulls- Seacock & Thru-Hull Primer/Pre Information Photo Gallery by Compass Marine How To at pbase.com
and valves- Replacing Thru-Hulls and Seacocks Photo Gallery by Compass Marine How To at pbase.com


The triangular thru hull base in your picture above looks like the one shown in the first url and is called a flanged adapter plate. It has a female NPS thread that screws onto the thru hull and a male tapered NPT thread that screws on to the ball valve. It does need to be bolted through the hull so it isn't very easy to do it in the water.


So I don't see any easy way of doing it right in the water. If you could dive under and stuff a foam ball in the hole, then you could unscrew the existing ball valve. Then replace it with a Groco flanged adapter. When you do, you will almost certainly need to cut off part of the thru hull's straight thread so it will seat properly. Then you will have to somehow drill through the hull for mounting bolts, ream the hole out for the tapered screw head, push them in from underwater with some sealant under the head and tighten them up with nuts on the inside. Only then can you screw on a new ball valve and be secure.


There is way, way too much to go wrong doing this in the water. I would strongly recommend hauling the boat and do it in the sling.


It is a good thing that you forgot your valve a few days ago. You were about to just screw a NPT thread onto a NPS thru hull.


David

"It does need to be bolted through the hull so it isn't very easy to do it in the water."

No it doesn't.

http://dreamgreen.org/boat-parts/182-through-hull-backing-plates

http://www.groco.net/SVC-MAN-07/Sec4/PDF/IBV-FBV-TB.pdf

"SEACOCK INSTALLATION
FIGURE-1 shows a sample seacock installation with two possible methods ofmechanicallyfasteningshown. On the left side is the method of bolting through the flange, backing block, and hull. On the right side is the method of bolting through the flange and into the backing block, but not through the hull. We consider either method acceptable, as both represent a safe and secure installation."

Agree with everything Dave said. I just did 13 of these and would not attempt this job in the water -- especially on my first changeout.

The bible has been written on through hull replacement. Dave and someone else have posted two chapters. Here's the third. If you read this material, it will answer all of your questions.

Seacock Backing Plates / Alternate Method / No Through Bolts Photo Gallery by Compass Marine How To at pbase.com

If you don't want to through bolt, you can bond the backing plates to the hull with 5200 or epoxy as the above details. I used epoxy and am extremely pleased with the results.

Awesome. Thanks for the backing plate info and the link. Need to read it more thoroughly.

I was just going to use 5200, or would epoxy be the better choice?

Also, does the flange/backing plate take the place nut on the thru hull or does that nut stay on? Actually, that nut on the thru hull must come off or I would have hell removing that thru hull in the future if I cover the nut up with the backing plate and epoxy.

Pack Mule said:

I feel much better now , thank you . I can put my nitroglycerin pills back in my pocket .

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??????

Sorry for the scare! I scare myself sometimes!

Capt.Bill11 said:

"It does need to be bolted through the hull so it isn't very easy to do it in the water."

No it doesn't.

Seacock backing plates

http://www.groco.net/SVC-MAN-07/Sec4/PDF/IBV-FBV-TB.pdf

"SEACOCK INSTALLATION
FIGURE-1 shows a sample seacock installation with two possible methods ofmechanicallyfasteningshown. On the left side is the method of bolting through the flange, backing block, and hull. On the right side is the method of bolting through the flange and into the backing block, but not through the hull. We consider either method acceptable, as both represent a safe and secure installation."

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I buried bronze bolts in a thick backing plate epoxies to the hull.

It is probably the toughest, most damage resistant setup on the whole boat.

This is one of those threads that everybody has an opinion of "it ain't no big deal", but when water comes in to my boat, I get the "this wasn't in the brochure" type feeling.

Thanks to everyone who contributed to this wacky thread.

As always I appreciate any and all opinions. And as in life, it's up to me to pick the best route that best suits my skills and situation.

As of this evening, my boat still floats.

Likelihood x Consequences = Risk.

I truly wouldn't hesitate to do this in the water. Although, I safely plan and execute unconventional maintenance activities regularly and have spent many hours in my previous life training to stop medium pressure and volume seawater leaks.

I believe cardude01 was asking pertinent questions. I do agree that if it is an NPS fitting, a Groco adapter, would be a good solution. I do not agree that a combination thread NPT/NPS thru hull fitting (yes, they make them) is inherently bad for this application. Everyone has made the assumption that it is NPS. I do have to wonder if it was factory installed or dealer installed, as there appears to be a circular cut out area in a liner for a backing plate that was not used. Interesting that they did use a Groco valve for the install.

I respect the opinions of those who would not consider this, as it is truly a matter of experience and risk management, but I do have to inquire...

How well prepared do you feel to mitigate an unplanned emergency leak in your boat if you are unwilling to attempt a minor low risk repair in a controlled fashion?

Cardude, the Groco Flanged adapter, screwed to the Groco matching plate which is epoxied to the hull is the best way to go. Angus did a really nice job of installing his.

After seeing those bung things in your earlier post, I had to put some in stock. Very cool tool.

"the Groco Flanged adapter, screwed to the Groco matching plate which is epoxied to the hull is the best way to go."

The hassle comes when the fitting fails, your 150lb tool box goes ballistic falling off a wave.

Epoxy will load the laminate its stuck to , but with a set of bronze thru bolts , the fitting may bend , but should stay in place.

Lakes bays and river service , sea tow can help,

out off the shelf , prevention , self preservation is the better choice.

Since you are going to pull the boat, why not just do the job right and install a proper seacock.

FF I like your if it's worth doing, it's worth over doing attitude. In this case I'd feel very safe with the flange bolted to the plate with out through bolts.
An awful lot of people get away with just screwing a ball valve on the end of a thru-hull fitting and it's pretty rare to have one break.

TDunn said:

Since you are going to pull the boat, why not just do the job right and install a proper seacock.

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Inferring that the Groco flange setup is inferior to a "proper" seacock?

If so what are all the key elements required to be a "proper" seacock and does the flange setup fail to meet them?

What happens when the newer style ball valve seacocks versus the older style tapered plug style fails open and haulout isn't immediately possible? Would the flange style where a new ball valve could be immediately be replaced be safer considering the function of a seacock?

As I see it the advantage of a seacock versus the flange and a ball valve is one less joint that might leak. Another consideration is that the entire seacock (except for plating on the bronze ball in the valve part is the same metal so there will be minimal electrolysis issues. In contrast, it is likely that the flange and the ball valve could be made from different grades of bronze (the ball valves may even be brass if you cheap out), which increases risk of electrolysis.

In the unlikely event that the seacock fails you are pretty much going to have to haul out to do the replacement. However if the seacock is bolted to a backing plate and not through bolted, you could replace it as easily as you could a ball valve. For example, when I installed my seacocks on my glass boat, I put in fiberglass backing plates which were drilled and tapped for the seacock mounting bolts. The thru-hull has its nut on it, so I can, in theory, remove my seacocks by unbolting from the backing plate and then unscrewing them from the thru-hulls. If they are thru bolted you will have to haul to replace them.

TDunn said:

Since you are going to pull the boat, why not just do the job right and install a proper seacock.

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During a haul-out last week I discovered that the boat had 5 frozen sea cocks (I repurchased it, after a 7 year hiatus, two months ago, and needed a proper survey for hull insurance).

Canoe Cove Marina has excellent yardmen and Ross there rebuilt all five in about four hours, bead-blasted and all, to new specs. I was grateful that a job that requires hauling was done then and there. It embarrasses me to know that this condition was escaping my attention as a priority.

So take a moment to visit your sea cocks and give them a turn now and then. They will then welcome you when you need them.

Extraordinarily small issues compared to what usually goes wrong with boats.

I see nothing bad and a little good for the Groco combination.

TDunn said:

As I see it the advantage of a seacock versus the flange and a ball valve is one less joint that might leak. Another consideration is that the entire seacock (except for plating on the bronze ball in the valve part is the same metal so there will be minimal electrolysis issues. In contrast, it is likely that the flange and the ball valve could be made from different grades of bronze (the ball valves may even be brass if you cheap out), which increases risk of electrolysis.

In the unlikely event that the seacock fails you are pretty much going to have to haul out to do the replacement. However if the seacock is bolted to a backing plate and not through bolted, you could replace it as easily as you could a ball valve. For example, when I installed my seacocks on my glass boat, I put in fiberglass backing plates which were drilled and tapped for the seacock mounting bolts. The thru-hull has its nut on it, so I can, in theory, remove my seacocks by unbolting from the backing plate and then unscrewing them from the thru-hulls. If they are thru bolted you will have to haul to replace them.

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I've had both and I think the flanges and ball valves are tougher. If you haven't seen and hefted the Groco components you might be surprised by how robust they are. I bonded the flanges to the backing plates with 5200 . . . in addition to bolting them together. That assembly is then epoxied to the hull and further reinforced by the through hull. The flange-to-ball-valve joint is sealed with pipe dope and teflon tape, deeply threaded and extremely strong and tight. The overall assembly feels much heavier duty than the original seacocks which were not through bolted and weakly bonded to plywood backing plates. I seriously doubt the metals are dissimilar and I can guarantee you that . . . despite Hopcar's excellent prices . . . there's nothing cheap about Groco fittings.

Angus, what are you going to do with the SSC in the third picture?

Hi, Parks. I'm putting fresh water flushes on the raw water intakes for the two mains, the genset and the air cond pump. Can't see that getting the salt out will hurt anything and they should make winterizing easier.

"An awful lot of people get away with just screwing a ball valve on the end of a thru-hull fitting and it's pretty rare to have one break."

Until someone steps on it.

Remember Murphy was an Optimist!

FF said:

Until someone steps on it. !

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Yes valves do indeed get stepped on. A few years ago a marine insurance inspector (where do they get these guys) stepped on an engine through hull on a large vessel my brother owned. The through hull survived fine, but the valve handle was closed while the vessel was moving. Yup it supplied water to one of the engines.

Guess whose insurance company paid for the new engine and labor?

I give...... The obvious answer should be the the surveyors, but I suspect your brother's did????

Rogerh said:

I give...... The obvious answer should be the the surveyors, but I suspect your brother's did????

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Yup, started with brother's and subrogated so where the final dollars came from were likely the "pool."