THRU HULLS

J

james

New member
I have been wondering about thru hulls on c-dorys.

mine are metal,but I have seen a few with plastic.

thanks for any info.

James
ps love reading this board.
 
I cannot tell you which thru hull is the best, just what I did and the reasoning.

The plastic thru hull does not fit as flush as the metal ones, which concerned me, a little. I think the metal ones are a little stronger, but with today’s plastic, I believe they (the plastic ones) are more than adequate. Metal is more expensive than plastic. Corrosion is not a problem with plastic, while it can be with metal. Metal thru hulls are either brass, stainless or chrome. The only metal one I could find in the size I wanted was brass. What it finally came down to was what would look best on the boat. Brass would not match the other metal items on my boat so I got a plastic thru hull that matched the boat color.
 
Hi James.
Used brass for our wash down pump. So far no problems to report. Since it's under the water line we weren't too concerned with the looks. Dave is probably right about todays plastics but metal just seems like the way to go to me.
Good boating,
Dale
 
James, Most boat yards reccommend metal thru-hulls below the water line and plastic or Marelon above the water line only. They are looking at long term, in the water useage. They also assume the metal thru-hull will be connected to the boats bonding system. A whole new can of worms! Roger, Dreamer
 
Do not use brass below the water line! Brass is an alloy of zinc and copper. It is it's own battery in an electrolyte such as salt water. It will disintegrate and crumble and your boat will sink. Make sure any thru hulls are bronze, stainless steel, monel or if synthetic, delrin.
 
Dreamer":1v242tsx said:
They also assume the metal thru-hull will be connected to the boats bonding system.
Click to expand...

Ok, having just installed a bronze thru-hull, what am I supposed to connect the two, oddly enough, different sized screws on the seacock to? We boat only on fresh water, so I'm guessing I probably don't need to connect to anything; or do I?
Al
 
I would think that unless you are keeping the boat in the water it would not be a problem. The main concern would be galvanic corrosion , due to stray current.

James
 
The boat's always in the water when it ain't froze! We just put it in today and I'm hoping it won't come out, except for trailering, til early November.
 
Moose: I believe bonding is for lighting protection. All metal parts on my sailboat including the mast were wired to a ground plate. Don't know if you need to due that on a small powerboat. Jack on C-Otter.
 
I have the very old version of the paperback book.... Your Boat's Electrical System... which says bonding is used to control stray or galvanic currents. Things may have changed since then. John
 
Moose - they're talking about "electrical bonding", which is where you remove coating from mating surfaces to ensure conductivity.
 
Lightning protection aboard boats can be a complex engineering problem involving far more than 'bonding'. Basically 'bonding' is just making sure that all items of electrical potential, galvanic, 110V, 12, 24, 26V AC/DC are properly grounded to a common "plate" so stray currents or potentials do not stimulate damaging electrical properties.... John

I searched lightning protection on boats on the internet.... quite complex
 
Short story on our encounter with lightening in the Bahamas. There were 5 of us with F-31 trimarans with 40 ft masts, all ungrounded. There was 1 twin masted sailboat (wood) about 100 ft away with heavily grounded masts through large copper plates attached to the hull underwater. Lightening storm came right over us, which of us got hit? Yep, you guessed it, the twin masted sailboat -- blew all the electronics and windvane right off the top of the forward mast, quite a bright show too. Nobody hurt. Collectively, we came to a couple of conclusions: 1) Maybe NOT grounding the mast/boat is the way to go, or 2) Park near someone who is grounded -- let's the lightening find the easier source to ground!
 
Back
Top