SailNet Community banner
  • SailNet is a forum community dedicated to Sailing enthusiasts. Come join the discussion about sailing, modifications, classifieds, troubleshooting, repairs, reviews, maintenance, and more!

Old disused through-hull maintenance?

2K views 14 replies 8 participants last post by  FreeAgent 
#1 ·


This old through hull should be tended to before I drop the boat into the water next week. Anyone have advice? Boat is new to me, spent a relatively mild winter on the hard. Photo is from October. Looks the same now.

Previous owner taught sailing on the boat and used and maintained it actively, but was from the school of "whatever works" maintenance.
 
See less See more
1
#2 ·
Looks almost like an ancient DS transducer with a fairing block. Perhaps 70's?
If not using it again, remove it. Grind a chamfer @ 12 degrees (+ or -) into the edge and lay glass cloth and epoxy until flush. Sand down and paint.
i.e. restore the bottom integrity in that area.
 
  • Like
Reactions: RichH
#3 ·
Oof. You are correct, I think. 1969 Cal 25.

I have my grinder ready to go but was thinking of just cleaning out the cracks and creating a good surface for some epoxy to adhere to. I'd like to have more experience with fiberglass before taking on something under the waterline like that.
 
#11 ·
I'd like to have more experience with fiberglass before taking on something under the waterline like that.
My first project on my little boat was to cut out glass over a molded in gate-valve thru-hull, and put in a new proper thru-hull with seacock.

So on my first ever boat I did my first ever fiberglass project and it involved two holes beneath the waterline!

It went great. I did several dry runs so I had everything thought out in advance. It looks good and is probably stronger than the rest of the boat.

While I agree with the others that if it ain't broke don't worry about it, if your chief concern is fear of fiberglass I also say don't worry about that!
 
#5 · (Edited)
Best is to use an angle grinder and simply grind/sand off all the external protruding metal ... you'll need to continually cool the ground surface with water to prevent overheating the fiberglass.
Once the surface is ground FLAT to the hull, simply punch the remaining through-hull into the hull ... then follow Olsen34s recommendation to form a proper patch.

The 12:1 taper (both side of the 'hole') ... just measure the thickness of the hull, multiply by 12 to arrive how much DIAMETER of the surface is to be removed by the tapering process .... the 12:1 taper doesnt have to be perfect, just close enough.
Eg.: .5" thickness X 12 = 6" diameter
 
#6 ·
There will be the other fairing block on the inside with the threaded stub of transducer. Could be just a lump of putty. Should remove all and grind back the area to clean and maybe lay down an epoxy patch .(Remove nut and punch out from inside easier than cutting)
 
#7 ·
If it's solid and wasn't leaking last season, and you don't want to get into removing it and doing a major fiberglass repair, then leave it. Or if it is indeed an old depth transducer and you don't have one (but would like to), remove it and use the hole to put in a new transducer.
 
#9 ·
Thanks all. I will get inside and get a good look at the other side of the fitting, and make the call on removing it.

My primary jobs are 1. getting the hairline crack in the rudder -- where the clamshell meets -- drained of any water, ground out, filled, and painted (might do without removing and do a more thorough job next winter when I pull the boat and drop the rudder for storage.) 2. Scraping interior flaking paint and repainting (I'm assuming some lead content in there) and un-tweaking the boom. (See my other thread if curious)

I'm new to this, all advice appreciated thoroughly! Cheers.
 
#8 ·
As Jim said.

My first reaction was to call a surgeon and get that lump removed. But then again, if it is a solidly installed transducer, and all the crud is just cosmetics, fairing compound that is letting go, it is not critical or unsafe. Chip or pry away the crud and if the business end of everything looks solid, just re-fair it and save the long job for a more convenient time.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top