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Thru-hull installation

footrope

Contributing Partner
Blogs Author
I need to correct my second sentence from my previous post. "Is the dope not a good lubricant and sealer when applied? And if I get frustrated with thread tape, I will just use dope only. We're only talking 16 psia and less than 3 psi delta-p.

The cheap thru-hull is pipe thread on the bottom. Found out when trying to dry fit all the hardware yesterday. So back it goes to Second Wave, today. It's not worth spending much time on speculation, but other than the weird top fitting, it looks "normal." There's probably a commercial application, like penetrating walls (bulkheads) or floors (decks) that uses this oddball.

The valves I received have the triangular base, not as compact to install as the round, and orientation will have some additional challenges. It's going to be a long, hot weekend.

As far as the suggested use of 5200 as thread sealer, I agree that it is a unfortunate shortcut. When owners don't know, or don't know better, they just go away satisfied because there were no go-backs due to leaks below the waterline. On small boats, owner maintained, that might sit unattended for weeks, we should do it right for each other.

Interesting perspective on screened thru-hulls. The same guy that helped me with the bronze fittings got me the B-A thru-hulls, with no screens. He said he wouldn't use screened types because they (screens) cause problems when hit by underwater obstructions. I guess he hit a rock on a thru-hull once and the screen somehow made it worse. Must be a power boat thing, but I didn't ask him about it.
 

footrope

Contributing Partner
Blogs Author
Screened thru-hull wrench

I decided to use the screened variety. I had to figure out how to tighten it without messing up the screen. It finally occurred to me that the fitting had enough metal to drill shallow holes that fit a winch tool. Can't wait to install it.
 

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larossa

Member II
Screened or UnScreened Thru Hull

Craig,

I was wondering about using a screen on my engine water intake. I'm in the Great Lakes area and I will be replacing the thru hull with a sea cock over the winter. The PO has a bronze "high speed" thru hull. I can't imagine my Ericson 31 C being a "high speed" cruiser. Anyway, I was unsure if I need a screened thru-hull. My previous boat, a Tartan 10 it did not have a screen and once it was plugged by a minnow of all things. Otherwise, in the ten years I never had a problem "un screened". What would the rationale be for choosing a screen or not? Any thoughts would greatly be appreciated.

Thanks,

Brian Walter
E 31 Nemo
Novi, MI USA
 

footrope

Contributing Partner
Blogs Author
A matter of opinion & personal experience

Hi Brian,

It is possible to block or plug any thru-hull. I chartered various inboard diesel sailboats for a few years, but I've never had one get blocked. This Ericson, which I've owned and sailed for 5 years, had a screened type. No problems SO FAR (knock on bronze) here in Puget Sound and the cruising grounds to the north. In my opinion, the screened type are less likely to get plugged with weeds and other flotsam and jetsam that you might encounter while motoring. Garbage like that will usually drop away if you shut off the engine for a few seconds.

If you can figure out a way to get sand or fine pebbles into the thru-hull, it could trap the particles and cause some problems that the unscreened would not. I also have a Groco raw water strainer - highly recommended regardless of thru-hull type.

On a fixed keel sailboat, with the thru-hull between the keel and rudder, I can't think of a downside of the screened type. My miles and variety of experience are pretty low compared to many here on the board, however. I look forward to additional input.
 

rwthomas1

Sustaining Partner
I cannot tell the diameter of the thru-hull from the pic however I would be more concerned that the screen would restrict the flow by a fairly large percentage. This obviously could be delt with simply by increasing the diameter of the thru-hull used. There are pros and cons to screened and unscreened. Pick your poison. RT
 

footrope

Contributing Partner
Blogs Author
An update

I cannot tell the diameter of the thru-hull from the pic however I would be more concerned that the screen would restrict the flow by a fairly large percentage. This obviously could be delt with simply by increasing the diameter of the thru-hull used. There are pros and cons to screened and unscreened. Pick your poison. RT

A belated response to Rob. The screened thru-hull is a 3/4, same as the original. I will be watching engine temperature tendencies closely.

Below are the installation pictures. The backing plate is 5/8" thick fiberglass sheet, individually cut and fit for each valve. The difficulty I had figuring out how to install the valves so that the thru-hull fittings were flush is kind of embarrassing now. At first, I worked on getting the fitting seats built -- with limited success, because the valves never fit so things stayed in the correct orientation with everything together. Working inside to align and orient the backing plate and valve amounted to chasing a ghost.

What I finally realized was that I needed to build up the seats temporarily so that the valves & plates could be held in place and glued down with the fitting flange in the perfect orientation with the bottom. Then I could finish off the fitting seats and put it together. So, with the help of a friend, we got it done without much more frustration. The seats were never perfect fits, but I achieved the goal of having a surface for the flat part of the fitting to tighten against, and a uniform, thin space on the 45 degree countersink that holds the polyurethane sealant. I used 3M 4200.

Now I'm fighting the worst weather in 18 years to get back in the water before going back to work on January 5th.
 

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rwthomas1

Sustaining Partner
Oh man, I feel for you! Those pics bring back memories of fighting with my thruhull installation. Working in that tight space under the sink really sucks. Looks like you had the smarts to remove the sink.... I didn't think of that until I was done. :esad: Good luck with it and yes, the weather of late SUCKS on the NE coast too. RT
 

footrope

Contributing Partner
Blogs Author
Thanks, Rob. It made it more light and it feels less confining. Very important when I practically have to dislocate my left shoulder to reach under there and work. But, I ended up taking the sink out since I had to replace the fresh water spigot for the foot pump, way over on the left (facing aft). No access at all because of how close the sink sits. In fact, it's no bargain trying to get the sink out due to the close fit.

There was also an occasional seep from the water supply line to the new main faucet I installed. I can get two wrenches on it now. And there was a vent spigot, that I removed when I re-plumbed the water fill to both tanks, that left a hole in the counter. I will either plug that or lead the hand sprayer up there an add a beauty ring.

I also found when removing the drain hoses that the tail pieces had rotted badly. They were made of some kind of brass colored material. So I found new drains for it. Ellen polished the rusty spots from the sink, so we'll see how long that lasts.

Stay warm, Merry Christmas!
 

WBurgner

Member III
Sink

You didn't happen to look for a sink replacement did you? I am still trying to find a suitable replacement for our sink.
 

footrope

Contributing Partner
Blogs Author
Bill,

I gave up on the new sink in favor of polishing the old one. I did find there were plenty of sinks available, but I only found one deep sink (around 9 in.) that would fit without modifying or replacing the countertop. Fisheries Supply in Seattle has quite a large selection in their 2007 and 2008 catalog, if you can lay your hands on one. Best of luck to you, but I didn't find a palatable replacement solution either for cost or work involved.
 

WBurgner

Member III
Sink

I hoped you had found one. After considerable looking I am afraid we will have to go with a custom order from Elkay. Big bucks, though. Before doing so I will remove the existing sink to see if there is anything I can do to the countertop to accept sizes available.

Thanks for the response.
 

Gary Peterson

Marine Guy
Here in Lake Erie we fight seaweed during the summer and a few times I had to remove my raw water inlet hose and back flush to remove weeds. I had a screened raw water inlet thru hull and no interior raw water filter. This winter I am removing the thru hull screen and installing a sea water strainer under the sink so I can clean it easier. A few fellows have had the small fish issue in their raw water inlets. A messy job to clean.
 

kiwisailor

Member III
Blogs Author
Nothing like resurrecting an old thread but seeing as I will also being tackling this job in the coming months I'll ask those who have been down this road before for their input.

First question is Groco sell two types of seacock the FBV and BV. Should I go with the FBV or the top of the line BV?

The FBV is below.

attachment.php


The BV is the all bronze top of the line seacock.
attachment.php


In addition Groco now sell a pre-drilled 1/2" backing block with threaded insert anchors. They don't specify what they are made from and also should I look towards 5/8" blocks rather than these 1/2" blocks or fabricating my own blocks as others here have done. Are these blocks up to the job?
attachment.php
 

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toddster

Curator of Broken Parts
Blogs Author
You've probably already done this, but I would start by taking the dimensions from the Groco spec sheets, plus the dimensions of whatever needs to screw into them, plus any hose curvature, and make sure there is enough room in your boat for them! (I wasted a lot of time sending for and returning parts over this issue.) But maybe that's not as much of an issue on bigger boats.
 

footrope

Contributing Partner
Blogs Author
Answer and an update

Hi Mike,

I don't know the price difference, but the bronze handles don't corrode and I suspect they are sturdier (more sturdy?). After eight years mine are doing just great. I'd do the bronze handles again.

I think 1/2" thick backing blocks are fine if they're not wood. You can make the blocks out of anything that is mostly impervious to water. Note that in my case round blocks would not work without trimming them because they're so close together. I used 5/8" fiberglass sheet because it was free. Plus I didn't want to drill any bolt holes all the way through the hull. So, I tapped the backing blocks and used short bronze screws. The 5/8" is an eighth inch better for that. The thru-hulls are plenty long enough.

I hope this is helpful.

Update: The seacocks have been trouble free since installation 8 years ago. I used a 3/4" thru-hull with a screen for the engine raw water inlet. No problems, but I have wondered about the flow restriction lately. Depending on how it looks inside, I may remove the screen. I recently disassembled the raw water system between the seacock and the Oberdorfer raw water pump. The thru-hull and seacock are 3/4", the strainer is 1/2" and the elbow attached to the Oberdorfer reduces to 3/8". Are there bigger Oberdorfers out there? I might look. The raw water side of the heat exchanger is at least 1/2".

I have been thinking about making a tool to scrape out the inside of the thru-hulls while the boat is in the water. We hauled out today at Shilshole for a couple weeks and I might do a little prototyping.
 
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kiwisailor

Member III
Blogs Author
Hi Mike,

I don't know the price difference, but the bronze handles don't corrode and I suspect they are sturdier (more sturdy?). After eight years mine are doing just great. I'd do the bronze handles again.

I think 1/2" thick backing blocks are fine if they're not wood. You can make the blocks out of anything that is mostly impervious to water. Note that in my case round blocks would not work without trimming them because they're so close together. I used 5/8" fiberglass sheet because it was it was free. Plus I didn't want to drill any bolt holes all the way through the hull. So, I tapped the backing blocks and used short bronze screws. The 5/8" is an eighth inch better for that. The thru-hulls are plenty long enough.

I hope this is helpful.

Update: The seacocks have been trouble free since installation 8 years ago. I used a 3/4" thru-hull with a screen for the engine raw water inlet. No problems, but I have wondered about the flow restriction lately. Depending on how it looks inside, I may remove the screen. I recently disassembled the raw water system between the seacock and the Oberdorfer raw water pump. The thru-hull and seacock are 3/4", the strainer is 1/2" and the elbow attached to the Oberdorfer reduces to 3/8". Are there bigger Oberdorfers out there? I might look. The raw water side of the heat exchanger is at least 1/2".

I have been thinking about making a tool to scrape out the inside of the thru-hulls while the boat is in the water. We hauled out today at Shilshole for a couple weeks and I might do a little prototyping.

One new product from Groco is their SSC port. It allows quick access to the raw water intake and it could also be used to simplify winterizing raw water system or as a an emergency alternative raw water intake. If I have the space I may install one of these on the raw water seacock.
attachment.php

[FONT=Arial, Helvetica, sans-serif]Add an SSC to the top of any seacock to allow instant emergency bilge pumping, or to simplify winterization and cooling system flushing.[/FONT]
[FONT=Arial, Helvetica, sans-serif]IN AN EMERGENCY: While the connected engine is running, close the seacock and remove the quick release plug. Excess bilge water will be pumped overboard by the engine raw water pump. Add GROCO Bilge Strainer to pump out remote bilge locations. See Illustration[/FONT]
[FONT=Arial, Helvetica, sans-serif]FOR WINTERIZATION: Close the seacock, remove the quick release plug and insert the service adaptor (included). Anti-freeze can be pumped into the cooling system.[/FONT]
[FONT=Arial, Helvetica, sans-serif]FOR SYSTEM FLUSHING: Close the seacock and insert the service adaptor. Dockside water can be used to flush the cooling system with the engine running at idle speed. See Illustration[/FONT]
 

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Shelman

Member III
Blogs Author
Nothing like resurrecting an old thread but seeing as I will also being tackling this job in the coming months I'll ask those who have been down this road before for their input.

First question is Groco sell two types of seacock the FBV and BV. Should I go with the FBV or the top of the line BV?

The FBV is below.

attachment.php


The BV is the all bronze top of the line seacock.
attachment.php


In addition Groco now sell a pre-drilled 1/2" backing block with threaded insert anchors. They don't specify what they are made from and also should I look towards 5/8" blocks rather than these 1/2" blocks or fabricating my own blocks as others here have done. Are these blocks up to the job?
attachment.php

I have used both lines of the Groco sea-cocks the BV with the bronze handle is a much higher grade and looks like the difference between and American made product vz a Chinese made product when compared to the FBV. The BV has a much smoother throw and closes with more overlap of the ball inside the sea-cock. Also with the FBV sometimes the lip of the ball gets caught on the plastic seat just as it closes so you think it is closed all the way and it actually is not, and sometimes the FBV is so tight to operate my wife cannot get it to budge, the FV series is flawless!. I can heartily recommend the BV over the FBV if you can afford the difference. Also the FB has a stainless a stainless ball instead of the chrome plated brass ball of the FBV. Both have the very convenient reversible throw handle.
The backing plate is made of fiberglass or more probably G-10 and is a nice option which will save you much time aligning the through bolt holes, which I thought was the hardest part of the install. the thicker backing plate would give more threads to grab and would be a welcome benefit.

Here is my install: http://www.ericsonyachts.org/infoexchange/entry.php?183-seacock-replacement

and further reading: http://www.pbase.com/mainecruising/replacing_thruhulls

and: http://www.pbase.com/mainecruising/backing_blocks
 
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Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
More than one 'right answer'

If you are interested in a one-piece winterizing-enabled engine water intake, this fitting from Forespar is really neat.
Some pix in a blog entry.
http://www.ericsonyachts.org/infoexchange/entry.php?140-Coupler-Shaft-Seal-and-Antifreeze

I used it a month ago, and with our recent week of 22 degree weather it is wonderful to have the whole engine raw water circuit protected.

The valve has three positions: outside water, off, and inside via the hose fitting. It is epoxied to a G10 backing plate which is epoxied to the hull. The original lip on the threaded thru hull piece was ground off after the epoxy cured. It's one very strong installation.
 

footrope

Contributing Partner
Blogs Author
Hi Mike,

... snip ...

Update: The seacocks have been trouble free since installation 8 years ago. I used a 3/4" thru-hull with a screen for the engine raw water inlet. No problems, but I have wondered about the flow restriction lately. Depending on how it looks inside, I may remove the screen. I recently disassembled the raw water system between the seacock and the Oberdorfer raw water pump. The thru-hull and seacock are 3/4", the strainer is 1/2" and the elbow attached to the Oberdorfer reduces to 3/8". Are there bigger Oberdorfers out there? I might look. The raw water side of the heat exchanger is at least 1/2".

I have been thinking about making a tool to scrape out the inside of the thru-hulls while the boat is in the water. We hauled out today at Shilshole for a couple weeks and I might do a little prototyping.

2018: Earlier in this 10-year-old thread there was a discussion of the need for a screen on the engine thru-hull. Several of you chimed in with experiences and opinions and everyone was correct. I opted to install the screened 3/4" thru-hull, which was the Buck Algonquin, I'm pretty sure. There was also a question from me about bonding the thru-hulls to prevent de-zincification. I chose not to re-bond my new ones after the old ones were bonded and they were still losing zinc. I suspect that they were only losing zinc from the flanges, which is bad enough, but they were still quite serviceable when I removed them. The stems were fine where I cut them about an inch above the nut.

Before we left on our Aug-Sep cruise to Desolation Sound, I had the shaft and prop zincs changed and the bottom scrubbed by a diving company. The divers reported that the screen on the thru-hull crumbled when they were cleaning and inspecting them. This was not a surprise since I have been observing that screen deteriorate a little more at each haulout. It was losing zinc (turning red) and it's not surprising since the screen was not part of the casting. It was a separate piece and stuck in a groove at the flange during manufacturing. So, I made a note to self and carried on.

Fast forward 6 weeks. At the last place we anchored on the way south, Blakely Harbor on Bainbridge Island, the thru-hull sucked up some weed and all but choked off the seawater flow to the heat exchanger. When we were a few minutes outside the entrance on the way out, I noted much more steam from the exhaust than usual (we always have a wisp once the engine warms up). It seemed that there was less water flow from the exhaust also. We throttled back and observed the engine temp, which stayed at 180 degrees the whole time. We went a little further out before shutting down and cleaning the dirty strainer and looking at the impeller and hoses on the seawater pump. All looked good but when we started up again, still very low flow. We turned around and stayed at reduced rpm and anchored back in the bay to work on the problem.

The next easiest thing in the system to check was the thru-hull. I pulled the hose off and with the valve open there was only a trickle. We have a stick, a wooden dowel from a giant sucker or a birthday balloon. It was long enough to use for a plunger and after a few hard jabs the plug was pushed down and out. I got the little water fountain I was expecting. Another check of the strainer found a strip of eel grass and after re-assembly we were on our way again, about two hours later than our original departure time. It is probable, if the screen was still in place, that shutting down the engine would have let the weed drop off the thru-hull, but that's not a sure thing. We were already informed, from this thread, how to clear it. For the foreseeable future we'll be without a screen and not particularly worried about it. Blakely Harbor has plenty of blobs of fine weed floating around at the surface, perhaps naturally occurring or maybe anchored boats are bringing it up.
 

bgary

Advanced Beginner
Blogs Author
I pulled the hose off ... after a few hard jabs the plug was pushed down and out. I got the little water fountain I was expecting.

That gives me the heebie-jeebies. Yeah, I know it was the right thing to do to solve the problem, but... yeesh

(it used to bug me when I had to pull the dummy-plug to install the knotmeter paddlewheel on boats, too. It'll all come out in therapy someday.)
 
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