Association Forum - How to abandon a thru hull safely

Assn Members Area · Join

Home.

Association Forum

Ships Store

Cruising

Racing

Technical Tips

Photo Gallery - New

Boat Search - Updated

Manuals & Brochures

Swap Meet

Links

Officer Flag Line & Staff

Bylaws & Constitution

Members Area

Join the Association

Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.

Association Forum

Username:	Password:
Save Password
Forgot your Password?

All Forums

Catalina/Capri 25/250 Sailor's Forums

Catalina 25 Specific Forum

How to abandon a thru hull safely

New Topic

Topic Locked

Printer Friendly

Author

Topic

Gloss
Master Marine Consultant

Member Avatar

USA
1916 Posts

Initially Posted - 03/16/2003 : 09:01:50

Hi folks

My recently acquired 89WK has two thru hulls up near the bow, located about 6 inches to each side of the center line. Both are for electronics which were abandoned and disconnected. One is a wheel for a knotmeter, the other for a depth sounder. Both have flanges with about a 2 1/2 inch diamater, so the hole is less of course. I am imagining that I am sailing along some day and one of these devices fails and I have a huge rush of water coming in. The devices have instrument readouts mounted on the cockpit bulkhead which are no longer wired up, and both have "SR Mariner" on them. I did an Internet search for this company and they have a website, and are located in New York. Their prices are outrageous. They want 390 for the knotmeter, and 500 for a digital depthmeter. In their spare parts list, they want 5 bucks for a square 9 volt battery.
I wouldn't mind having a knotmeter, but 390 for a new one is ridiculous (uh oh, did I misspell that?)

The DPO abandoned these instruments, leaving holes in the hull and bulkhead. He then installed a depthsounder with a to hull transducer, and a GPS, (by Navman, with no manuals of course) both mounted in the cabin bulkhead, where they are useless from the cockpit.

So here are my options:

Buy another knotmeter from them, and hope that the hole is the same size, maybe upon further search find a discount supplier of this product.

Buy another manufacturer's knotmeter, if I can find the same size thru hull impeller assembly.

Abandon both thru hulls and hopefully I can make a sound patch. I'm pretty good at fiberglass/epoxy work, but have never taken on a job with this serious of potential consequences if I screw up.

Does anybody make some kind of metal plate you can use to plug up a thru hull? Maybe I could use a bronze pipe fitting thru hull and cap it off.

I do plan on relocating the depth sounder readout from the cabin bulkhead to the cockpit bulkhead too.

I'll bet I'm not the first one to have this problem/concern.

Any thoughts?

Frank Gloss
89WK/TR

Edited by - on

Leon Sisson
Master Marine Consultant

Members Avatar

USA
1893 Posts

Response Posted - 03/16/2003 : 10:40:07

Frank,

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>The DPO abandoned these instruments, leaving holes in the hull and bulkhead. He then installed a depthsounder with a to hull transducer, ... mounted in the cabin bulkhead, where they are useless from the cockpit. ... options: ... Buy another manufacturer's knotmeter, if I can find the same size thru hull impeller assembly.<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>I'd try to find a fishfinder that uses either the same speedo sender unit, or at least the same size speedo thru-hull hole. If you haven't considered a fishfinder as a sailboat instrument, I urge you to do so. They're not just for finding fish. Most include speed as well as depth, and some include a digital volt meter (so you can tell when it's time to turn off the trolling motor while there's still enough cranking power left to fire up that 200HP outboard<img src=icon_smile.gif border=0 align=middle>).

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>Abandon both thru hulls and hopefully I can make a sound patch. I'm pretty good at fiberglass/epoxy work, but have never taken on a job with this serious of potential consequences if I screw up. <hr height=1 noshade id=quote></BLOCKQUOTE id=quote>Go for it. I had to "move" a thru-hull to install a different water tank. The hardest part was the hand wringing, whining, and procrastinating before picking up the 5" right angle grinder. Here's a quick overview the procedure I used:

<ul><li>Remove any old parts in the hole to be filled.</li></ul>

<ul><li>On the inside, grind the hull surface around the hole for about an additional 2" or 3" radius. Don't try to dig deep, just expose clean fiberglass laminate. This is only to clean and abrade the surface.</li></ul>

<ul><li>On the outside, grind back a tapered bevel around the hole at a 10:1 or 12:1 angle. That is, if the hole is 2" in diameter, and the hull is 1/2" thick, grind out a shallow dished recess around the hole to a total diameter of 12" or so, and a center depth of 1/2". In other words, the hole should end up with a sharp edge. (10 x 1/2" = 5" radius, plus the 2" center hole)</li></ul>

<ul><li>Cut out two or three fiberglass cloth disks the size of the cleaned area inside the hull. These will be applied first to form a backing for the rest of the repair.</li></ul>

<ul><li>Coat cleaned and abraded area inside the hull with epoxy resin and lay in those first two or three fiberglass disks. Apply additional resin as required to wet out the cloth. While that's curing stiff, cut more disks as follows.</li></ul>

<ul><li>Cut out some fiberglass cloth disks to fill the hole from the outside. Start with about 3 disks the diameter of the ground area, and then cut more disks, each about 1/8" to 1/4" smaller. Don't bother to cut more than about half a dozen to ten disks before applying what you've got. The shape of the remaining depression can change as the repair progresses, thus changing the needed size and shape of the disks to fill it.</li></ul>

<ul><li>Coat the ground out tapered area outside the hull with epoxy resin and lay in those first two or three full diameter fiberglass disks. Apply additional resin as required to wet out the cloth. These disks should be large enough that their edges end up standing proud of the hull. Don't try to make any of the disks so small that they are entirely below the final hull surface. You want the entire repair to consist of saturated fiberglass without pockets of resin only. Don't worry too much about the repair getting too high at this stage. That grinder will make short work of any excess material. </li></ul>

<ul><li>Keep cutting and laminating until you notice an uncomfortable amount of heat build-up, or until the repair is getting so thick and lumpy that you aren't sure where the current laminating surface is relative to the intented final hull surface. Then take a well deserved break while that mess cures enough to grind and sand.</li></ul>

<ul><li>Grind and sand the most recent layers to approx. the final hull surface. Use a faring batten to check progress.</li></ul>

<ul><li>Using a fairing batten, check to see what size and shape of cloth is now needed to bring the repair closer to the final surface.</li></ul>

<ul><li>Continue cutting, laminating, curing, and grinding until the entire repaired area is within about 1/32" of the final shape. </li></ul>

<ul><li>Mix up some epoxy based filler putty, and proceed as if filling and fairing a small shallow dent in a car.</li></ul>

<ul><li>Apply bottom paint, gelcoat, or other finish as required.</li></ul>

That's all there is to it!<img src=icon_smile.gif border=0 align=middle> It took me about two hours total, split between two or three evenings after work. I am now fearless when it comes to making and repairing holes below the waterline.<img src=icon_smile_big.gif border=0 align=middle>

-- Leon Sisson

Edited by - Leon Sisson on 03/16/2003 11:07:15

Edited by - on

rclift
Navigator

Members Avatar

USA
152 Posts

Response Posted - 03/16/2003 : 12:27:41

Frank,
A couple of years ago I replaced the SR mariner knotmeter. After contacting the company they took the 20+ year old broken one in trade for the new one plus $100. With it came a new set of cables and thru hull. I'm sure prices have gone up but you might want to call them and see what they will do.

My SR depthmeter is mounted in the same location as yours but isn't actually a thru hull. It is mounted and sealed to the inside of the boat.

Ray Clift
Buzz 1361
oregon

Edited by - on

matsche
Captain

Members Avatar

USA
280 Posts

Response Posted - 03/16/2003 : 18:17:24

I too am in the process of replacing my depth gauge and knotmeter. I talked with Cory at SR last week. He said if I'd send in the display part of the units, that they would give me 50% of list for replacement units. And it can be an upgrade to a different unit. I'll probably opt for the same unit as I like the analog readout better and they're less expensive. If you're interested, the web site for SR is http://www.sr-i.org/sr/default.asp.

Also: Cory said the the sending units were all the same diameter so they should fit in your existing holes. A big plus for me!

John Matsche 1985 Cat-25 TR/FK

Edited by - matsche on 03/16/2003 18:19:21

Edited by - on

Gloss
Master Marine Consultant

Members Avatar

USA
1916 Posts

Response Posted - 03/16/2003 : 18:55:49

John,

thanks for the good information. Keep those good thoughts coming in

Leon, That was a great explaination of how to patch a hole.

I also found a Navman knotmeter that has a bronze thru hull for their impeller. Looks stout.

Frank Gloss
89WK/TR

Edited by - on

tinob
Master Marine Consultant

Members Avatar

USA
1883 Posts

Response Posted - 03/17/2003 : 09:09:20

Frank,

I also had a deranged depth sending unit and after a chat with the factory was made an offer that I couldn't refuse. It was as Ray and John described. The sending unit and read out cost $129 with the old readout turned in. Made me wonder why the wanted the old readout but not the old sending unit. That was four maybe five years ago still can't figure what was inside the readout that they wanted it so.
In any event I'd not be concerned that the thru hulls might fail, just make sure that your VHF is fully operational and that you have sufficient PFDs aboard.<img src=icon_smile_big.gif border=0 align=middle>

Val on the hard DAGNABIT

Val Bisagni]<img src="http://im1.shutterfly.com/procserv/47b3df11b3127cce94709c5ff2e90000000010" border=0>

Edited by - on

RichardG
Admiral

Members Avatar

USA
990 Posts

Response Posted - 03/17/2003 : 13:03:09

Frank:

My boat also came with a vintage speedo which never worked. However, I didn't fix/replace it, as my handheld GPS is sufficiently accurate for me in providing speed info.

As for the thru-hull in the bilge, I simply "capped" it with the bronze (brass?) cap which came with the unit. I removed the paddle-wheel and all cable.

But something had to done with the readout on the cockpit bulkhead, as the back of it had lots of sharp points directly above the galley sink, thus making doing dishes a potentially deadly endeavor. In lieu of patching the hole (getting a perfect color match is difficult), I sawed the back end of the unit off (great revenge!), removed all inards and made a teak "frame" for the inside. The following porthole is the final result.

<img src="http://im1.shutterfly.com/procserv/47b3dd36b3127cce950ac5e820e40000001610" border=0>

RichardG 81 C25 SR/FK "Sanity"

Edited by - on

Gloss
Master Marine Consultant

Members Avatar

USA
1916 Posts

Response Posted - 03/17/2003 : 13:47:29

That porthole is a great idea. My plans for the bulkhead holes is to mount a new knotmeter, and then to relocate the depthmeter/fishfinder. They are both on the starbord bulkhead. In the port bulkhead I plan to mount a Plastimo double reading lighted compass. Should look really neat there, and at night the light should be cool, as well as functional of course.

But since Plastimo's are made in France, I think, I am about to change my mind on that plan.

Frank Gloss
89WK/TR

Edited by - on

matsche
Captain

Members Avatar

USA
280 Posts

Response Posted - 03/17/2003 : 18:56:09

Val: I 'think' they want the display part as more of a 'proof of purchase' rather than anything instrinsic to the unit. May have something to do with keeping their re-sellers happy by not undercutting them on new business. They don't ask for the sending units, since (in my case) my boat would sink.

John Matsche 1985 Cat-25 TR/FK

Edited by - on

Gloss
Master Marine Consultant

Members Avatar

USA
1916 Posts

Response Posted - 03/17/2003 : 19:11:00

SR wants 195 for a new unit. Their thru hull has a tapered hole cut into the hull. They show a special bit for 50 bucks on their website. Since this hole is already there, and the new unit fits it I'll go with that one. I know that a GPS will also give speed but it is not as instantaneous, and I don't always use mine if I'm just sailing around the lake. I have a Garmin GPS map 176C which is a chartplotting GPS and it is great.

So this will leave me with one hole in the boat with an unused transducer. I'll either patch it, or leave it until I need a new Depthmeter

Thanks to everyone for your input. someday when I finish getting the boat up to par, I'll learn how to post pics.

Frank Gloss
89WK/TR

Edited by - on

Topic

New Topic

Topic Locked

Printer Friendly

Jump To:

Association Forum

Notice: The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.