The first thing that strikes me is that the bronze thru-hull fitting would have no way to be bonded if you intended to. The bronze would possibly be subject to corrosion and the Forespar product would not. A matching Marelon thru-hull would keep the whole assembly non-conductive. RT
Frank Langer
1984 Ericson 30+, Nanaimo, BC
But I have read that one should either use all bronze or all marelon, but never mix the two (Nigel Calder and Don Casey, I think).
Frank.
Frank.
NateHanson
Sustaining Member
Well, I don't think bonding is an issue, because I'm quite sure you don't want to bond your thru-hulls.
The only reason I can think of not to mix bronze and marelon fittings, is that they probably expand and contract differently with heating and cooling. So perhaps the threaded interface could work some and maybe fatigue or loosen? I think this is probably a stretch in reality, especially with everything in the bilge all the time, where temps are going to basically be water temp all the time.
The only reason I can think of not to mix bronze and marelon fittings, is that they probably expand and contract differently with heating and cooling. So perhaps the threaded interface could work some and maybe fatigue or loosen? I think this is probably a stretch in reality, especially with everything in the bilge all the time, where temps are going to basically be water temp all the time.
models and materials quandaries
Which Forespar model is being discussed? The one with the triangular base that takes three screws or the newer "OEM style" with the rectangular base and no screws?
The later one uses a buttress thread and can *only* mate up to the matching threaded thruhull piece.
As to using a bronze thruhull with the older Forespar seacock, I would just "cut to the chase" and dime up the forespar folks and ask them. It's their product, based on their engineering and R&D. They will advise you.
I have not phoned Forespar, but have asked for technical advise from several other marine product companies and *always* received helpful and forthright assistance. (Harken is tops in this regard, FWIW.)
We all have some annecdotal "field testing" to relate, and will be glad to advise as best we can... but going upstream to the source is always your best move, if you can do so.
Please keep us posted,
Loren
Which Forespar model is being discussed? The one with the triangular base that takes three screws or the newer "OEM style" with the rectangular base and no screws?
The later one uses a buttress thread and can *only* mate up to the matching threaded thruhull piece.
As to using a bronze thruhull with the older Forespar seacock, I would just "cut to the chase" and dime up the forespar folks and ask them. It's their product, based on their engineering and R&D. They will advise you.
I have not phoned Forespar, but have asked for technical advise from several other marine product companies and *always* received helpful and forthright assistance. (Harken is tops in this regard, FWIW.)
We all have some annecdotal "field testing" to relate, and will be glad to advise as best we can... but going upstream to the source is always your best move, if you can do so.
Please keep us posted,
Loren
Thats not what I have read... I understand that bonding has been discussed plenty here before though. I don't have the Calder book near at hand but IIRC any and ALL metal in contact with seawater should be bonded. My Grocos have bonding points on them. RT
NateHanson
Sustaining Member
I should reword my earlier statement.
I'm quite sure that I don't want to bond my through hulls. I think it's simply a better way to make a battery. If they're not bonded they won't be subject to electrolysis.
I'm quite sure that I don't want to bond my through hulls. I think it's simply a better way to make a battery. If they're not bonded they won't be subject to electrolysis.
thru hulls
A Couple of years ago I replaced all the thru hull and seacocks on the boat.
If my memory is correct
1. There are two types of thread used on bronze seacocks. one is tapered I beleive at the top and the other is not.
2. A bronze Seacock will not fit on a marelon thruhull
3. I checked with forespar technical assitence and they were very helpful in choosing what ends would work with what.
4. I am not at the boat but I think I had to use the same type of seacock as thru hull but could use bronze tail pipes. Forespar does make a couple variations of seacocks and that may alter the results.
5. I dremel is very usefull in removing the bronze thruhull. Cut off the bottom and pull out the thruhull.
6. be sure to uses plenty of 4200
A Couple of years ago I replaced all the thru hull and seacocks on the boat.
If my memory is correct
1. There are two types of thread used on bronze seacocks. one is tapered I beleive at the top and the other is not.
2. A bronze Seacock will not fit on a marelon thruhull
3. I checked with forespar technical assitence and they were very helpful in choosing what ends would work with what.
4. I am not at the boat but I think I had to use the same type of seacock as thru hull but could use bronze tail pipes. Forespar does make a couple variations of seacocks and that may alter the results.
5. I dremel is very usefull in removing the bronze thruhull. Cut off the bottom and pull out the thruhull.
6. be sure to uses plenty of 4200