Repower with a Beta Marine 25 - Thru-Hull Replacement

[Desertboater]

When the Beta 25 engine installation was completed, the focus moved to providing sufficient cooling water to the engine. The original Swedish thru-hulls & valves were still in place - these valves are gate valves and some were pretty tight to turn. Two things pushed me into replacing all the thru-hulls and valves - the first was the need for more cooling water flow in the summer temperatures in Lake Mead, Nevada and the second was a general concern over the age and condition of the bronze thru-hull fittings and attached gate valves. An internet search lead to several Albin owners that have replaced their thru-hulls - two sites really caught my attention. The first was on the Albineers of BC web site titled "Sea Cock Replacement"
http://www.albinbc.com/technical/member ... eplacement
and the other was Compass Marine's excellent article about replacing thru-hulls and seacocks
http://www.pbase.com/mainecruising/replacing_thruhulls

One issue of concern was galvanic corrosion due to the use of different materials - bronze vs brass are the most common, but as I found later when inspecting all the thru-hulls on our boat, sometimes other materials are used. The other was the miss-match between straight and tapered threads when a ball valve is screwed to a thru-hull.

The deciding factor in our case was what we found under the deck of the head - the old 'straight through' toilet thru-hull had been capped with a steel galvanized cap and the sink drain valve had galvanized fittings. This lead to the thought 'wonder what has been fastened to any of the thru-hulls?' which in turn lead to the thought "how would the Captain react if the Engineer reported flooding due to a failed thru-hull?"

This photo explains it all.

Why Replace Thru Hull.jpg

The paper work that came with the boat showed that the black water tank was installed in the mid-1990s and the toilet thru-hull was probably capped then, so these galvanized fittings had been in place for 20 years or so.

Since the boat was in the shop, it was easy to work on the thru-hulls. Following Compass Marine's excellent write-up, Groco IBV Flanged Adapters were purchased along with marine ball valves and assorted bronze pipe fittings. The flanged adapter internal has straight thread to match the thru-hull and tapered thread on the external to match the ball valve. The flanged adapter and backing disc look like this:

Flanged Adapter.jpg

Rather than making fiberglass backing discs, GPO-3 or G-10 fiberglass sheets were purchased from McMaster-Carr and backing plates fabricated following Compass Marine's Alternate Method [http://www.pbase.com/mainecruising/backing_blocks].

The following photos show the progress of this project. For a detailed step by step description, go the the Compass Marine web pages and you will probably be very impressed by the information he has provided on many marine projects in addition to seacocks and thru-hulls.

Some thru-hulls after being removed from the Albin - the ones that had the galvinized fittings showed plenty of pink spots in the bronze where the zinc had disappeared.

Removed Thru-hulls.jpg

Flanged Adapter and fiberglass backing plate - drilling the holes for the silicon bronze studs. The same WW II vintage drill press was used with a 4 inch hole saw to cut the circular backing discs.

Drilling.jpg

Masked off area of the hull with all paint removed by rotary wire brush and cleaned with Petit Degreaser. Note the old Elastomuffler support has been cut off to allow for future installation of Centek water lift muffler.

Masked Area.jpg

Trial fit of the cooling water thru-hull, valve and hose fitting. Note the prop shaft and stuffing box in the lower left corner of the photo.

Trial Location.jpg

Fiberglassing the backing plate onto the hull was a learning experience - fortunately West Systems fiberglass epoxy is easy to use and they have excellent how-to articles on line. This was the first one so the fairing along the edge of the backing plate was pretty rough. By the time I got to the ones hidden under the cabinet or head floor, they looked professional - of course no one will see them.

Thru Hull Glassed.jpg

Final installation of the thru-hull, valve & fitting assembly after tightening the thru-hull but prior to installing silicon bronze lock washers and nuts. I used Sika Flex rather than 3M 5200 in case some future owner needs to replace these in 30 years or so.

Final Thru Hull.jpg

The only challenge to this project was that the minimum size for the flanged adapter was 3/4 inch - no 1/2 inch ones are made. So several thru-hulls were increased in size to 3/4 inch with the exception of the sink drain in the head. There just was not enough room to install a flanged adapter there. The testing that Compass Marine did on a ball valve / thru-hull assembly gave reasonable assurance that the head sink drain would be adequate without a flanged adapter - I could not see how you could put any appreciable side load on this since one can just barely get two fingers on the valve handle to turn it.

Before anyone gets nervous about their thru-hulls, especially if you have taken off the original Swedish gate valves and installed new ball valves with NPT thread on the straight thread of the thru-hull, please read the Compass Marine article about testing seacocks and thru-hulls, especially the ball valve / thru-hull assembly.

However, if you have pink spots visible on any of the brass surface of your thru-hull, further evaluation would be in order.

[kerrye]

What was your opinion on your original thru hulls which had not had galvanized steel attached to them? My boat still has the original thru hulls and gate valves as far as I know. When I bought the boat in a partially disassembled state, the PO told me he had planned to change the thru-hulls (the engine raw water thru hull had been replaced when a new engine was installed). When I looked closely at the thru hulls I could detect no evidence of deterioration and the original gate valves operated smoothly so I could see no reason to change them. In looking at the pictures of your cut up thru-hulls, even the one with the galvanized cap seems to have been pretty solid despite the pink.

[Desertboater]

Yes the thru-hulls seemed to be quite strong - After making two part way thru the metal cuts during the removal, I tried to bend a section of the large toilet discharge thru-hull and could not bend it.

The challenge with copper alloys for marine service is knowing what the particular material really is - I have not been able to find information about the specific manufacturer of the thru-hulls used by Albin in Sweden. If silicon bronze or aluminum bronze was used, there should not have been dezincification as there is little to no zinc in either of those bronzes. The photos on the Albineers of British Columbia (albinbc.com) website (project on seacock replacement) showed thru-hulls that were two orders of magnitude worse than mine and the article states that the annual shipyard check reported them as OK.

If there had not been galvanized fittings installed on the thru-hulls, we would have probably changed out only the cooling water intake thru-hull. All the other thru-hulls, with the possible exception of the one in the closet, could never have significant side loads placed on them. Having slipped one time before the repower with the deck boards up, I ended up with one foot on the raw water hose near the thru-hull/gate valve taking a lot of my weight. The thru-hull did not fail. But since that one needed to be replaced with a 1 inch thru-hull, the research to learn how to replace a thru-hull lead me to all the 'bad news stories' which caused a change in direction to go with the Groco flanged adapters.

Was it necessary? Probably not. Do I feel more secure boating in very cold water on remote regions of the Snake river -yes.

[kerrye]

I'm under the impression that BC boats tend to stay in the water year round. Anyone know if that is correct. If that's true, the thru hulls are subject to harsh conditions. My boat was a Maine boat so spent about 6 months a year in the water before moving to TX where is spent 8 yrs in a barn before it came to me and now it spends a few months in the water each. So even though my boat is as old as a BC boats, presumably the thru-hulls could be expected to be in much better condition. Mine certainly didn't show the kind of corrosion those BC thru hulls had.

[WillieC]

Mine is an old BC boat, last residing in Bellingham, with no trailer to speak of in its history to my knowledge, until we put one under it. I replaced the engine raw water through hull this last season and the old one was in fine shape. The valve on the inside wasn't in such good shape, showing pink. I went back with all bronze and upsized it one size to 3/4". I was a bit intimidated with the fiberglass work required to "do it right" per MaineSail, so I wimped out and went back to the original method which gave 40 plus years of service on this boat. Now I am a fiberglass expert, and I regret my choice. Future replacements will be by the book. Next on the list is the galley drain with a gate valve that takes about fifty motions of the wrist to close.

[Beta Don]

Any hole in the boat below the waterline deserves close attention because with very little warning (or none at all) they can lead to the sinking of your vessel

If the boat is 30+ years old and you even suspect the fittings are original, at the very least they need to be removed, carefully inspected and rebuilt or replaced. Parts to rebuild 30 year old fittings can be hard to find and it may be hard to tell what they are made of. For metal boat fittings, there's true bronze and then everything else

Unless you know for sure what they're made of, it's best to replace them. A friend with an '80's Island Packet, which is supposedly a higher end boat, discovered that he had no seacocks at all. Bronze thru hulls with Chinese 1/4 turn ball valves screwed on them from the factory - The very same ball valves you can buy for $10 or $15 at Home Depot

When I was replacing everything on my A27, the bilge pump overboard fitting was installed too close to the chine in the hull to be able to fit a proper backing block, so they used none at all. The nut on the inside rode on the stepped part of the chine while the head of the thru hull was on the flat portion of the hull. When they tightened the nut, it cracked the thru hull . . . . . and it had been that way for 30 years when I discovered it

At the very least, remove everything, carefully inspect everything and repair/replace as needed - A 30 year old boat really needs a good look because your life can depend on a $10 part which may not have been installed properly 30 years ago

Don

[DesertAlbin736]

I spent a good part of yesterday over at our boat (on its trailer where we keep it stored). Hard to tell if the through hull fittings are original or not, but they probably are. Looked through all the documentation & receipts that were handed down from previous owners, & saw no mention of replacing thru hulls, but all gate type valves had been replaced with 1/4 turn ball valves, probably hardware store ones like the ones on Beta Don's friend's Island Packet, since the last previous owner was not a stickler about things being "marine grade".

Also looked through correspondence between former owners & various copies of registrations dating back to 1986. That's as far back as the history went, so I don't know about what, where, and how times it changed hands during the first 15 years of our boat's life including several name changes. Seems our boat resided in South Florida during the late 80s and made many crossings to the Bahamas. Another owner resided in Illinois. From about 1999 on it went to a new home in Ontario and from then on was primarily a fresh water boat. The trailer it's on now was bought new in 1999. The Canadian owner mostly used it mostly on the Canadian side of Lake Erie, and apparently passed away sometime prior to 2001, at which time the folks we bought from picked it up in the heir's estate sale and brought it back over the border and out to Idaho.

The Idaho folks renamed the boat "Nowell's Ark", a pun on the owner's last name, and kept it on the trailer at their place in American Falls, ID, mostly storing it in a barn. They cruised Lake Powell several times, plus a local lake near their home, and a couple of jaunts to the Gulf Islands, including trailering over to Vancouver Island by ferry and launching it at Port Alberni to run down the fjord to the west shore of Vancouver Island & the "Broken Group" of islands. By 2012 they had decided to move on from boating and switch to RV travel, so it mostly sat stored in their pole barn the last couple years until we came along in 2014, having seen it advertised on Craig's List. I was a little too smitten & determined to find an Albin 25, and agreed to pay more than we really should have, especially when the trailer tires they said were "new" turned out to be 10 years old, and the engine was a lot older then we thought. At the time there were only two other Albin 25's listed for sale anywhere in the US, and they were in Texas and Florida. A couple others were in British Columbia, but neither had trailers. I wonder if one of those BC boats could have been WillieC? To their credit, they did refurbish the interior which saved us a lot of work. But still, it was a lot of money for a very old boat. But our adventures with it since are priceless.

The Yanmar engine that's in it now was installed new in 1986, and four years later in 1990 they added the AquaDrive unit, which at that time cost $358. The engine had around 2000 hours on it by the time the Idaho owners replaced the engine hour meter, which read 537 hours when we took ownership and now reads 948 hours. So total engine hours now is around 3,000, give or take.

So anyway, here are our through hulls as they look now.

Overboard drain through hull ball valve for the head. Barely visible at right is the capped off drain for the stock vanity sink, which was removed & replaced by a shelf unit.

20171115_104059_resized.jpg

Y valve for the head. Arrow on the handle points to the side that's blocked, so in this picture it's lined up to be pumped out through the deck fitting, not drained overboard. The 20 gallon holding tank is on the other side of the wall at right.

20171115_104143_resized.jpg

Flush water inlet for the head, located under the hanging closet.

20171115_103931_resized.jpg

Drain line for the galley sink. It doesn't appear our boat ever had a raw water faucet as some A25's do, since there are no other thru hulls under the sink.

20171115_104227_resized.jpg

Raw water inlet for the engine. 3/4" line matches the size of the raw water pump inlet. This valve gets cycled more than any other, as we shut it every time we haul the boat so the raw water pump doesn't lose prime. The red hose with the in line strainer is the suction side of the diaphragm bilge pump.

20171115_112612_resized.jpg

[kerrye]

The thru hull for our raw water sink faucet is to the right of sink under the bunk and not under the sink cabinet itself.

[DesertAlbin736]

The thru hull for our raw water sink faucet is to the right of sink under the bunk and not under the sink cabinet itself.

If that's so, I'm sure it's capped off like the vanity sink faucet for the head. The exhaust hose also has a ball valve shutoff between the transom & muffler, located under the quarter berth in the aft cabin.