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Catalina/Capri 25/250 Sailor's Forums

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Replacing through hulls

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Dan86
Navigator

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130 Posts

Initially Posted - 08/09/2004 : 22:37:49

I am planning a haul out for next monday and would like advice from this auspicious group. I want to replace my though hulls with the catalina direct versions. I believe i am just swithching out for new ones, I do not have the old brass style of tu hull. Is this as easy as it looks, and what are the things to watch for while doing this? Thanks a ton in advance. Dan 86 fin keel, TR

Edited by - Dan86 on 08/09/2004 22:38:16

ClamBeach
Master Marine Consultant

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3072 Posts

Response Posted - 08/09/2004 : 22:46:36

Don't scrimp on the caulk. Make sure your caulk is compatible with the thru-hull material. (cheap plastic thru-hulls can be incompatible with some caulks). BTW I like 3M 101 the best of all the non-adhesive caulks I've used.

Snug 'em up so caulk is expelled all the way around. Clean the excess caulk up with a rag (maybe lotsa rags) dampened in thinner or diesel... let the caulk sit overnight and then give them the final tightening the next day.

Don't overtighten... cracking from over-stress is the worst thing that can happen to a plastic thru-hull.

Edited by - on

lcharlot
Master Marine Consultant

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Antigua and Barbuda
1301 Posts

Response Posted - 08/09/2004 : 22:57:57

Call Catalina Direct and ask if the new thru-hull kit comes with instructions - I would assume it does. The issues you have to have under control before you start work:
1. What is the inside and outside diameter, and length (relates to hull thickness) of the existing fitting? - you need these numbers to buy the correct replacement.
2. Is the existing through hull installed perpendicular to the hull surface or at an angle? Angled thru-hulls are often seen on depth sounders, where the transducer needs to point vertically down, but the hull isn't horizontal at that point. These installations require a levelling wedge, or the hull has to be built up with epoxy paste or fiberglass until you have the flat mounting surface you need. There may also be transducers and thru hulls manufactured with certain angles built in.
3. Find out from Catalina Direct what kind of sealant or bedding compound is used with the new fittings they are selling you, and if this sealant comes with the fitting as a "kit", or do you buy it separately?
4. Do you need new seacocks? If your boat has the old style Factory OEM bronze gate valves, you might want to think about replacing them with new Marelon non-corrosive seacocks. The old gate valves eventually seize up, and it becomes impossible to turn the handle to either close the valve if it's open, or open it if it's closed. Your boat is 18 years old, and if it's been kept in salt water all that time, the seacocks are probably way past their prime if they're bronze.

Good luck!

Edited by - lcharlot on 08/09/2004 22:59:02

Douglas
Master Marine Consultant

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1595 Posts

Response Posted - 08/10/2004 : 20:05:02

Dont use 3M 5200. (Dont Dont Dont). Use life caulk. Dont screw the flange / nut down tight the first day. Screw it down loose . The reason is so all the sealant is not pushed out. Let it cure for a day and then tighten it. This forms a better seal.