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To Hull Repacement with photos.

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Douglas
Master Marine Consultant

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1595 Posts

Initially Posted - 03/14/2002 : 17:36:58

Several people on this board have had questions about the Catalina to hulls. Their safty and how to replace them. Im posting the initial pictures and instructions step by step to make the process easy.
1) I disconected all the tubes and drain lines from the fittings.
2) I removed all the plastic valves and fittings exposing the to hull pipe. At this point I did find some corrossion between the pipe and fiberglass but since this boat was built in 1983 I figured it wasnt to bad.
3) I used a high speed motor and cutting wheel to slice or grind through the extra fiberglass and cut the pipe off as close to the hull as I could.

Time to do all this after gathering tools was 1 hour. Next step is to remove the pipe still remaining in the hole and grind the fibergass even with the hull interior. The following pictures are typical of Catalina to hull fittings. As I progress I will post more photos and instructions and ansure questions. I hope this helps some of you. <img src="http://im1.shutterfly.com/procserv/47b2dd35b3127cce9ca14d207f400000005410" border=0>The first pic shows the to hull as seen from outside with hull paint removed. <img src="http://im1.shutterfly.com/procserv/47b2dd35b3127cce9ca14dbdfeed0000004410" border=0><img src="http://im1.shutterfly.com/procserv/47b2dd35b3127cce9ca14dbdfeed0000004410" border=0><img src="http://im1.shutterfly.com/procserv/47b2dd35b3127cce9ca14db9fee90000004410" border=0><img src="http://im1.shutterfly.com/procserv/47b2dd35b3127cce9ca14d9e7ffe0000004410" border=0><img src="http://im1.shutterfly.com/procserv/47b2dd35b3127cce9ca14d987ff80000004410" border=0><img src="http://im1.shutterfly.com/procserv/47b2dd35b3127cce9ca14d85fed50000004410" border=0>

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dlucier
Master Marine Consultant

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Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 03/14/2002 : 18:07:55

Thanks. I appreciate you taking the time during your project to provide us information and guidance. Again, thanks.

Don Lucier, Northstar
C25 SR/FK

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Ken Cave
Navigator

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USA
148 Posts

Response Posted - 03/14/2002 : 23:05:51

Doug:

About time you finally did the good deed in replacing the to-hulls!

I might even let you travel with us to Desolation Sound this summer now that your Catalina is in pristine condition (and your wife makes the BEST lemon meringue anywhere)

How does the beginning of June sound?

Ken Cave

Edited by - on

OJ
Master Marine Consultant

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USA
4382 Posts

Response Posted - 03/15/2002 : 09:19:02

Hey Douglas, I'll be bringing OJ home in a couple weeks and the to-hull to thru-hull conversion is on the top of my todo list. One question: did you attempt to unscrew the to-hull pipe before you cut it off? How did you get the remaining pipe out after you the cut off the tail piece?
Really appreciate the time and effort you put into getting the photos placed on this forum. I think you're about to become the resident expert on this topic as well!
Steve Madsen
#2428
OJ(Ode to Joy)

[url="http://catalina25-250.org/photo0.htm/"]<img src="http://www.catalina25-250.org/photo/ode075.jpg" border=0>[/url]

Edited by - OJ on 03/15/2002 10:27:34

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jm
Captain

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Canada
290 Posts

Response Posted - 03/15/2002 : 10:08:51

You indicated that you cut through the pipe at the inside "volcano".
Did you extract the piece of pipe or insert the new thru hull through the pipe ?

Also, what type (marelon or metal) of thru-hull did you use, and what size ? (3/4" x 3" ? )

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c25sailor
Past Commodore

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USA
138 Posts

Response Posted - 03/15/2002 : 10:49:12

I found it easy to unscrew the pipe nipples after cutting through just the glass. One unscrewed very easily by hand (scary) and the other with the slightest help of a small pipe wrench. Once the pipe was out, finishing off the volcano was super easy.

I can't imagine leaving the cut-off piece, as readily available through-hulls wouldn't fit inside the old nipples. Remember you still need to attach a seacock to the through-hull. I ended up with a 3/4" fitting at the galley and 1/2" at the bow. I used bronze.

Ed Jakubas
Lucyna II
1982 TR/SK #2801
<img src="http://home.attbi.com/~c25sailor/images/RailwashProfile.jpg" border=0>

Edited by - c25sailor on 03/15/2002 10:49:56

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OJ
Master Marine Consultant

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USA
4382 Posts

Response Posted - 03/15/2002 : 11:05:26

Ed, when you say "cut through just the glass" I assume you mean just the built-up area around the pipe inside the hull? This built-up area around the the to-hull pipe is what people are referring to at the "volcano?"

Steve Madsen
#2428
OJ(Ode to Joy)

[url="http://catalina25-250.org/photo0.htm/"]<img src="http://www.catalina25-250.org/photo/ode075.jpg" border=0>[/url]

Edited by - on

Douglas
Master Marine Consultant

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1595 Posts

Response Posted - 03/15/2002 : 12:10:25

With regards to the inside. The volcano. I cut through both the fiberglass and the copper tube. Im as far as the picture shows so my next step is to remove what is left of the copper tube. Ill post more pictures as I go. I didn't try to unscrew the pipe first perhaps I should have. Ill try that on the one for the head raw water. As for expert its realy true. Expert = Drip under pressure.

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c25sailor
Past Commodore

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USA
138 Posts

Response Posted - 03/15/2002 : 12:48:56

Steve- yes, I cut through the volcano only. I just wanted to be sure I didn't stress a larger area in attempting the unscrewing effort (which, as it turned out, wasn't hard at all).

Douglas, great pics!

Ed Jakubas
Lucyna II
1982 TR/SK #2801
<img src="http://home.attbi.com/~c25sailor/images/RailwashProfile.jpg" border=0>

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OJ
Master Marine Consultant

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USA
4382 Posts

Response Posted - 03/15/2002 : 14:03:40

I don't know where this "volcano" term came from but if you had just called it an upside-down-snowcone I would havw known exactly what you were talking about from the start.

Steve Madsen
#2428
OJ(Ode to Joy)

[url="http://catalina25-250.org/photo0.htm/"]<img src="http://www.catalina25-250.org/photo/ode075.jpg" border=0>[/url]

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Ken Cave
Navigator

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USA
148 Posts

Response Posted - 03/15/2002 : 23:04:51

Hey guys:

All you have to do is use a Mikita four inch grinder and cut the pipe parallel to the hull-about an inch from the hull surface-then you have a flat surface to mount your bronze thru-hull! If you are not able to get the rest of the pipe out of the hole, just use a small file and nitch it-then use a pair of pliers to remove it-or an "easy-out" which is even easier to remove the rest of the pipe that is on the hole.

Hope this helps

Ken Cave

Ken Cave

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Douglas
Master Marine Consultant

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1595 Posts

Response Posted - 03/16/2002 : 15:52:42

I tried to remove the rest of the to hulls today and tried the unscrew them technique. No luck they were threaded all the way into the hull and would not budge. I had to cut them off with a thin grinding wheel and then remove the left over pipe. I used what is called a punch saw to cut the left over pipe inside the hole and then drove it out with a puch and hamer. Im working on the 2" head discharge now. Pictures to follow tomorrow. Its not a lot of fun to work on the boat right now. Snowing and cold but it has to be done.

Edited by - on

William Matley
1st Mate

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52 Posts

Response Posted - 03/17/2002 : 06:32:31

I took a slightly different tack at this problem that worked pretty well.
From the outside I whittled a round plug out of wood and tapped it into the hole. Then I took my drill with a 1" inch hole saw attached and using the wood plug to guide the hole saw, I smoothly and neatly drilled the whole pipe out of my boat. Then I ground the volcano flat, piece of cake!
Removing the waste holding tank to gain access to the "to hull" now that was the tough part.

Edited by - on

Mark Maxwell
Captain

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USA
329 Posts

Response Posted - 03/17/2002 : 13:13:49

William, that's exactly what I did. Whole project took less than an hour. I had done a replacement on my C22 as descibed by Doug and after grinding down the "volcano" I was completely covered in fiber glass dust. It took a long time to clean up the mess. I even had a shop vac running during the grind. The outside approach was much easier and a whole lot less messy.

Mark-
<img src="http://personal.jax.bellsouth.net/jax/l/c/lchaplin/unkarock/usflagwav.gif" border=0>
'Impulse'
C25 #533 DINN/FIN

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Ben - FL
Admiral

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880 Posts

Response Posted - 03/17/2002 : 19:59:04

A good remedy for fiberglass itch is to put baby powder on your skin before you come in contact with it. Works great. I always do it before climbing into the attic.

Safe voyages,
Ben, FL s/v Chick-a-pea C250wk

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William Matley
1st Mate

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52 Posts

Response Posted - 03/18/2002 : 07:18:10

This question is for the science minded readers. I have been looking at the hole I cut into my boat and wondered what is the pressure of the water that would be forced through that hole if my boat were sitting in the water? Any one care to enlighten me?

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Mark Maxwell
Captain

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USA
329 Posts

Response Posted - 03/18/2002 : 12:13:51

William, I am a Firefighter and figuring water flows is part of my job. The formula used is: GPM = 29.7 x d(squared) x (square root of) P

GPM = gallons per minute

d = diameter of opening

p = pressure at opening

You would need to figure out the PSI of the hull by dividing the Whole weight of the boat by the surface area of the hull in contact with the water (in square inches) Then there would be some change in your weight as the boat took on water. I've got no clue how to figure that one.

Now I've had to replace the knot meter pick-up with a plug while in the water and noticed that the psi of the water was not much maybe a pound or two (and that hole is about 2 inches in diameter)

So if you figure it like this it would be roughly: GPM = 29.7 x 1"(squared) x (square root of)2psi (just for example). Which is: GPM = 29.7 x 1 x 1.41 and that works out to aprox 72 GPM (I rounded up) That's a lot of water. If the inside diameter of your thru hull is 3/4" than that works down to about 24 GPM. Now you know <img src=icon_smile_big.gif border=0 align=middle>

Mark-
<img src="http://personal.jax.bellsouth.net/jax/l/c/lchaplin/unkarock/usflagwav.gif" border=0>
'Impulse'
C25 #533 DINN/FIN

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jm
Captain

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Canada
290 Posts

Response Posted - 03/18/2002 : 12:15:04

I'm beginning to think the original to-hulls aren't all that big a risk as made out to be, qualified perhaps by boat location?. I know they may work loose in some hulls, but having to use a piece of wood to hammer out the pipe, or other similar amounts of force to break the bond between the pipe and fiberglass volcano/hull, leads me to believe the engineering of these to-hulls wasn't all that bad. Perhaps those with their boats in salt water, or hull in the water for years at a time (i.e. never hauled out during winter freeze) may find the to-hull begins to loosen up - but other conditions may find the design does the job ! (i.e. fresh water, hauled out every fall, longer dry period). I know, I know, better to be safe than sorry..especially given the relatively small cost of the 'fix'.

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Douglas
Master Marine Consultant

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1595 Posts

Response Posted - 03/18/2002 : 13:20:25

Hi JM let me put it this way. To you it may not seem much of a problem however to those people who have lost a boat (SUNK) it is. Nature is kind of funny. There can be great forces exerted where you least expect. How can freezing water in a crack brake a concrette driveway apart. How can freezing water in a bottle shatter the container. If you freez a section of plastic or copper pipe under your house in the winter why do the pipes burst. Get my drift on this, the fitting is only as strong as its weakest point. 20 year old fiberglass bonded to a copper pipe that has some corrossion is a week point. Put water seeping or condensing in any space of the joint and you have a possability of failure. You cant save the boat if your not there when it happens. I would hate to launch my boat and go below to open the through hull just to see it start to crack or snap off. Worse yet to have a fin keel boat in the water all year, go to the dock only to see the only thing keeping the boat afloat is the dock lines. All of the fittings I have removed from my hull so far have been corroded and brittal. Its you call. If you trailer perhaps you will be fine and not need to do the to hulls. For me there was no opption. Im in the water all year (SALT) and I have seen it freez around my boat twice. Ill sleep beter knowing I have bronze through hulls.

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OJ
Master Marine Consultant

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USA
4382 Posts

Response Posted - 03/18/2002 : 13:40:56

Thanks to William Matley for a great idea on removing the old to-hulls. Now that's what I call "thinking outside the box" or hull in this case.

Steve Madsen
#2428
OJ(Ode to Joy)

[url="http://catalina25-250.org/photo0.htm/"]<img src="http://www.catalina25-250.org/photo/ode075.jpg" border=0>[/url]

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William Matley
1st Mate

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52 Posts

Response Posted - 03/19/2002 : 10:13:29

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
A good remedy for fiberglass itch is to put baby powder on your skin before you come in contact with it. Works great. I always do it before climbing into the attic.

Safe voyages,
Ben, FL s/v Chick-a-pea C250wk
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

I never plan that far ahead to use babby powder but I have a great remedy for removing the fiberglass that has ALREADY gotten into your skin. Take a foot long piece of duct tape and wrap it around your hand sticky side OUT. Then just pat down the offending area of your body that has fiberglass on it. The duct tape will pick it off clean as the tax man!

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OJ
Master Marine Consultant

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USA
4382 Posts

Response Posted - 03/19/2002 : 10:20:43

Now I'd like to know the origin of that technique!

Steve Madsen
#2428
OJ (Ode to Joy)

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William Matley
1st Mate

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52 Posts

Response Posted - 03/19/2002 : 10:31:15

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
William, I am a Firefighter and figuring water flows is part of my job. The formula used is: GPM = 29.7 x d(squared) x (square root of) P

GPM = gallons per minute

d = diameter of opening

p = pressure at opening

You would need to figure out the PSI of the hull by dividing the Whole weight of the boat by the surface area of the hull in contact with the water (in square inches) Then there would be some change in your weight as the boat took on water. I've got no clue how to figure that one.

Now I've had to replace the knot meter pick-up with a plug while in the water and noticed that the psi of the water was not much maybe a pound or two (and that hole is about 2 inches in diameter)

So if you figure it like this it would be roughly: GPM = 29.7 x 1"(squared) x (square root of)2psi (just for example). Which is: GPM = 29.7 x 1 x 1.41 and that works out to aprox 72 GPM (I rounded up) That's a lot of water. If the inside diameter of your thru hull is 3/4" than that works down to about 24 GPM. Now you know <img src=icon_smile_big.gif border=0 align=middle>

Mark that's great but as I think about it, that doesn't make sence. Lets see ... 24 GPM is a hell of a lot of water, 12 gal in 30 seconds, 6 gal in 15 seconds, 3 gal in 7.5 seconds, 1.5 gal in just over 3 seconds, yet you said that the pressure you experienced was just a pound or two.
Pressure is what I was wondering about. I was wondering how much pressure the new "thru hull" fittings had to deal with.

It seems to me that buoyancy is the key here. Science says "a body is buoyed up by a force equal to the weight of water it displaces" so if your boat weighed 6,000 pounds (for example) then you would need to know the wetted surface area and that will tell you the pressure per square foot or inch.

So what's the wetted surface of a normally loaded Catalina 25? Anyone know the answer to that?

Mark-
<img src="http://personal.jax.bellsouth.net/jax/l/c/lchaplin/unkarock/usflagwav.gif" border=0>
'Impulse'
C25 #533 DINN/FIN
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

Edited by - on

Mark Maxwell
Captain

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USA
329 Posts

Response Posted - 03/19/2002 : 13:35:22

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>Lets see ... 24 GPM is a hell of a lot of water, 12 gal in 30 seconds, 6 gal in 15 seconds, 3 gal in 7.5 seconds, 1.5 gal in just over 3 seconds<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

William, I didn't break it down at the time but now that you have it works out just about right. It took me about 1 second to make the switch and though the water bubbled in under very little pressure I had about a half gallon or so of water to soak up with two large bath towels.

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>It seems to me that buoyancy is the key here. Science says "a body is buoyed up by a force equal to the weight of water it displaces" so if your boat weighed 6,000 pounds (for example) then you would need to know the wetted surface area and that will tell you the pressure per square foot or inch.

So what's the wetted surface of a normally loaded Catalina 25? Anyone know the answer to that?<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

I think your right on with that. Once the psi is known for sure then you can plug that plus the size of the opening into the equation I gave to find the amount of water taken on only. Now that I think about it that psi is static not flowing. The psi needed in my formula is flow pressure. Which would be even less.

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>what is the pressure of the water that would be forced through that hole if my boat were sitting in the water?<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

I know GPM is not what you were looking for I just offer it up as additional info. Maybe an easy way to find the pressure would be to simply add a PSI gauge to a tee in the line at the thru-hull

Mark-
<img src="http://personal.jax.bellsouth.net/jax/l/c/lchaplin/unkarock/usflagwav.gif" border=0>
'Impulse'
C25 #533 DINN/FIN

Edited by - on

Leon Sisson
Master Marine Consultant

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USA
1893 Posts

Response Posted - 03/19/2002 : 21:06:14

<center>Stirring Muddy Waters</center>

Thru-hull Pressure:

After all that's been said about pressure and flow, I'm reluctant to add my two cents, but here it is anyway:

1 atmosphere = 14.7 PSI = 33' deep water column

1' deep water column = 0.45 PSI

So your deepest thru-hulls in a C-25 have less than 1 PSI pressure on them.

The water pressure at a leak submerged in rising bilge water is determined by the vertical difference between the waterlines inside and outside of the boat. There's a chart of flooding rates for various holes at various depths in Nigel Calder's "Boat Owner's Mechanical and Electrical Manual". A 1-1/2" hole at a depth of 1' (i.e. a broken head discharge line) will admit over 2,600GPH (Gallons Per Hour). So how big are your pumps?

As an aside, a popular 630GPH-rated pump, when tested, could only flow 630GPH at 13.6VDC and zero head (a.k.a. "open flow"). At 12.0VDC and 3' head (a much more realistic situation,) it only flowed 345GPH, or about 50% its advertised rating. That might be a good ratio to keep in mind when bilge pump shopping.

"To-Hull" Strength

When I first picked up my 1979 boat, it was being kept in seawater in Miami, and from what I gathered, had been in salt water for most all of its life. While I was off running errands, my well meaning crew tried to be extra sure the thru-hull (actually "to-hull") gate valves were closed. Two of the handles crumbled in her hand without the shafts moving. One of what we're calling "volcanos" at one of the the cockpit scupper "to-hulls" was cracked radially (like a real volcano cone) and leaking a bit. After checking for significant leaks, we didn't touch the below water plumbing again until after the boat was safely on a trailer 200 miles later. When I removed all of the Catalina "to-hulls" for replacement (except the swing keel cable pipe), I got two of them out with my bare hands. One came out with a slight crunch, and I unscrewed the other from the hull easily by twisting its gate valve body. There's a picture in Nigel Calder's "Boat Owner's Mechanical and Electrical Manual" of exactly how not to install a thru-hull, and it still looks better than the way Catalina did it.

"To-Hull" materials

The short pipe nipples that made up the "to-hulls" appeared to be brass; the metal was much too yellow to be either copper or bronze. While I was grinding down the "volcanos" at the "to-hulls" to prepare the inner hull surface for fitted teak backing blocks, the odor that seeped into my respirator was definitely polyester, not epoxy. The material used was almost certainly thickened gelcoat, which, although weak and brittle compared to modern epoxy, would have been cheap and readily available on the Catalina assembly line.

-- Leon Sisson

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tinob
Master Marine Consultant

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USA
1883 Posts

Response Posted - 03/20/2002 : 11:28:27

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
Now I'd like to know the origin of that technique!

Steve Madsen
#2428
OJ (Ode to Joy)
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

Steve,

We used a similar technique long before ducktape was invented. Ask any sailor going on liberty or standing inspection how they got all the little cruddies off their dress blues and and they will probable answer to a man, surgical tape so wrapped will clean it up pronto. I did it in the late fourties and fifties.

Val on ther hard DAGNABIT

Val Bisagni

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