Thru hull
- Thread starter Voyager1
- Start date
Great, thanks. That is that I was thinking but very new to doing repairs, thought I would check. The manual for current transducer I have spec. 2 and1/16 hole. I didn’t think they made a hole saw that size but apparently the do so I figured I would ask.
Probably designed for inside dimension of pipe. Tubing is measured by outside diameter, pipe is measured inside diameter. Of course, if the thru hull is the male to a pipe that clamps over it, then the pipe is 2-1/16" inside. What does the thru hull fit to? Maybe the extra 1/16" is intended to make a flexible 2" pipe fit more tightly. Maybe they just build in a little tolerance to avoid trouble on the assembly floor.
- Will (Dragonfly)
I agree with Don also. That small of a gap should be easy to fill and make water tight, if you even need to fill it. The bedding, I would think, should be more than adequate to handle it.
- Will (Dragonfly)
Read about installing a thru hull on MaineSail's website. He shows how to match a hole saw to a thru hull. The hole will be the thickness of the saw larger than the fitting to allow for sealant. The backing plate is also sealed and the face of the device mounted to the thru hull is sealed. You could put in a backing plate with a pilot hole, build up around the edge with thickened epoxy then drill a 2 inch hole.
You might wanna check out my thru hull removal technique.
https://forums.sailboatowners.com/index.php?threads/thru-hull-removal.184946/
https://forums.sailboatowners.com/index.php?threads/thru-hull-removal.184946/
I knocked out two of my throu hulls today for my instrument and a yard guy suggested cutting new thru hulls and glassing in the old. He said you are asking for leaks using the old ones. As mentioned above the old and new are about same size. Has anyone used old thru hulls or do you typically cut new ones.
I reused to old hole cuz they were reinforced. I'm not one to disagree with a yard guy but why do you think MORE holes is somehow better then less.
If the glass/wood/steel/etc. is good, why can't the old hole be as perfect As the day it was cut? I am one to argue with a yard guy, however. Good or bad, I don't assume the expert is an expert. They have their ways and it probably works for them but... . Maybe his method of fitting removal is more violent and shreds the edges.
Just my thoughts. I'm a woodworker not a glass worker.
- Will (Dragonfly)
Just my thoughts. I'm a woodworker not a glass worker.
- Will (Dragonfly)
HAPPY THANKSGIVING TO YOU ALL!!!
This past spring, we upgraded our navigational gear of old Raymarine and Datamarine gauges, displays, and radar. We (mostly the Admiral and I) pulled the cables through the original path by taping the end of the old to end of the new with rigging tape. We used the same through hulls as the previous transducers, as our thought process was that those locations were chosen as ideal. The Admiral, by the way, is also our self proclaimed "Safety Officer", was quite adamant against cutting new holes. Needless to say, we researched as much as possible. What it boiled down to was what the actual diameter of the holes drilled in the hull to receive those transducers. Make a long story short, cut off old transducer thru hulls, cleaned each area around the holes really, really well, and rebedded each transducer thru hull with 3M 5200. Per the Admiral's request, we put loose tissue around each thru hull, which are directly beneath our V-berth and spent the first three nights aboard once she was launched. Never found any soggy tissue. That was the start of this past sea sun, and she is still floating as of yesterday. If I were able to follow MS prescribed method using a backing plate, I would have, however, I think those are more for seacock thru hulls than transducer thru hulls. Also I did not have room to mount backing as he did.
Good luck with your O'Day projects, and if I can be of help, let me know......
s/v Faster Horses
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Sounds like you did a great job. My only concern would be that 5200 is "forever" - rated as not removable by 3M. There are below waterline marine sealants that are removable, like 3M 4000UV, 4200FC, and 4400BC. If you ever have to do this again, the 5200 will be very tough to deal with.
I replaced my transducers a few years back and they were in from the Hunter factory and they used 5200 and yes it was hard but did remove them and the housing was not in great condition
after removing but did get everything out and the new ones in with 5200 and yes the factory did use backing plates for them.
I also removed a few thru hulls that went bad and same thing was very hard and did have to replace the backing plates and I know 3m says not removable but not true.
Nick
after removing but did get everything out and the new ones in with 5200 and yes the factory did use backing plates for them.
I also removed a few thru hulls that went bad and same thing was very hard and did have to replace the backing plates and I know 3m says not removable but not true.
Nick
I agree with seadaddler, although 3M is a very strong product, any adhesive can be removed. I was fortunate enough that I could stand up beneath the hull while it was on poppets and work the area vigorously. After I removed the thru hulls, using a 5 in 1 on the exterior and a Dremel on the interior side, I cleaned the areas with solvents like paint thinner, WD-40, and others in very small quantities until the whole surface was free of any residue. I cleaned the holes until they looked liked what would have been original condition, and once you get down to it, you will know what that looks like. No sandpaper, I did not want to disturb the fiberglass in any way that might make it porous to moisture. I believe that the original builders made the holes just oversized enough so that the adhesive sealant could be put on the thru hull itself and form a continuous bond from the exterior to the interior.