Replacing above waterline thru hulls

[gregorybross]

I am going to replace the original above waterline thru hulls for bilge pump, propane locker drain and cockpit drain outlets. The originals are very cheap plastic and I would like advice on what others have used. West marine has the originals, marelon, nylon with stainless exterior covering and solid stainless. I think bronze is overkill. Any opinions?

Greg

 

[Ralph Johnstone]

Replaced seven above water thru hulls with SS a number of years back. The price was not particularly bad for nice shiny baubles. Even changed a number of vinyl handholes to SS which unfortunately was a little pricey. Really blew the budget that year but they still look good.

I'm sure the chandelry here has as good or better prices than most.

 

[FastOlson]

Either SS or Marelon fittings will probably outlast you...
Those old originals were likely an acetate or some other non-reinforced cast plastic that was also not UV resistant.

LB

 

[Bob S]

Greg,

Take some pictures. I haven't really looked behind the steering quadrant but am curious what kind of access you have on the MKIII.

 

[The Garbone]

It was a bugger working back there on my 78'. This thread reminds me I still have to fish that mag light out that fell down into the skeg.

 

[gregorybross]

Bob S - Yea it is going to require some serious boat yoga to get in there. I will post some pics.
Greg

 

[wufibugs]

Maybe Stu will weigh in, but do you think either Catalina or Hunter used something other than marelon for the plastic thru hulls? Mine are still there after 30 years and I don't think any plastic other marelon would still be in one piece.

 

[Claude L.-Auger]

Maybe Stu will weigh in, but do you think either Catalina or Hunter used something other than marelon for the plastic thru hulls? Mine are still there after 30 years and I don't think any plastic other marelon would still be in one piece.

If you don't mind me instead of Stu, I'll tell you that based on my having to change several of mine on my 1984 Hunter 34 I'm inclined to say they went with the cheapest plastic kind. Also based on the more or less 20 years life span before I replaced, I did not see a reason to use anything else and therefore replaced with the same type.

 

[Stu Jackson]

Maybe Stu will weigh in, but do you think either Catalina or Hunter used something other than marelon for the plastic thru hulls? Mine are still there after 30 years and I don't think any plastic other marelon would still be in one piece.

I don't know what they used. Mine are white.

To the OP, if you give use links to the three choices (OK, two would be enough, we know what SS is...) maybe we can help.

Otherwise, I agree with previous answers: your boat, your choice, Marelon if your boat is a keeper and family heirloom.

My boat's 27 years old and they are doing fine, including the wet exhaust.

 

[gregorybross]

Stu-
My wet exhaust is a bronze thru hull. The other 3 are the original plastic (i think it is polypropylene). The boat is not a family heirloom but if one of these very cheap plastic fittings breaks the boats waterline is dramatically reduced. I am just trying to beef up what I see as a vulnerability.
Greg

 

[Stu Jackson]

Greg, I understand completely. Get Marelon, metal is an upgrade, plastic should be avoided. I think you'd agree, not sure how much more help anyone could be.

 

[jrowan]

Greg, I understand completely. Get Marelon, metal is an upgrade, plastic should be avoided. I think you'd agree, not sure how much more help anyone could be.

PS. Marelon are good quality thru hull & valves, but they ARE STILL PLASTIC, just a different type of high density, proprietary plastic. They do not suffer from corrosion, but are affected by U.V. degradation over time. No material is perfect or will last forever. Here is a link which rates different types of thru hull materials:

http://www.forespar.com/what-is-marelon.shtml

Also FYI: Here is a pic of a cut out of an early Catalina 30, likely from the 1970's era. The stern has been cut off, as the poor C 30 is being parted out. It shows the plumbing connected to the scupper drains. It appears to be garden hose, as it has that unmistakable dark green hose color. I hope its not garden hose in the 1980's era Catalinas! But they sure did cut some corners & used very cheap plumbing fittings in the early days. The gate valves they used were meant for a house hose bib & they only glassed in domestic 1/2" copper tubing into the hull during wet layup & just hoped for the best. Many Catalinas from the 70's are still out there with these badly corroded gate valves that can snap off & sink their boat at any time. Scary thought. This is why newbies should have boats inspected by a surveyor, or at least a boat yard before purchasing. The fiberglass hulls will last forever, but everything else is another story.

 

[Bob S]

Here is a picture of mine. 19 years and they look pretty good. I wouldn't worry about them unless you see cracks. My wet exhaust is also plastic or marelon but due to the location under the belly I'm sure it doesn't see sun.If yours is bronze maybe a PO changed it out.

 

[The Garbone]

Since we are sharing.

Here is ours with the one to port broken. I replaced it with a nylon fitting (cheap). I did sand, prime and paint all 3 to protect from future UV issues.

The fun thing is the broken one is the out for the manual bilge pump. Not a big deal but the PO had installed a Y to said pump and was using it to pump waste overboard. Yummy , such fun.