Stanchions - Stainless or Alloy?

RobW

RobW

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Hi folks,
The stanchions and stanchion bases on our recently acquired 20 year old hunter horizon are in a pretty poor state with corrosion - cosmetically grim, upper wire holes elongated with wear and worst of all totally seized to the bases - on previous boats I have liked to remove the stanchions from the bases to get the winter cover on - I have tried most of the methods suggested in other threads to free them off with no success - but that’s not what this post is about!.

I have come to the (costly) conclusion that replacement of both bases and stanchions is the best course of action all round.

The current bases and stanchions are alloy - something like this:
http://www.seamarknunn.com/acatalog/Stanchions-Bases.html
(Other chandlers and products are available!)

The question is - can anyone offer an opinion why, as on so many production yachts, pushpits and pullpits are stainless steel, yet stanchion bases and stanchions are alloy?
From searching the interweb there does seem to be stainless steel replacements out there -and they are generally cheaper than the alloy - so what was the perceived advantage of fitting alloy in the first place?

Can't be weight - by the time you chuck in cruising gear for a family of four - the difference would be totally insignificant!

Any ideas?

Rob
 
I'm at this point too. The Moody has alloy bases and stanchions. I assume they are alloy so that there are no problems as they bolted on to the alloy toe rail. However the pulpit and pushpit are stainless are similarly fixed. I've yet to try to get the old stanchions out of the bases - the results of that might decide which way I go. I can't think that it matters as SS are commonly used and look nice IMO.
 
There was a time (when your boat was built) that alloy castings were much cheaper than SS fabrications so that is what was fitted. That is no longer the case. Cast aliminium is more expensive - even cast SS cleats for example are cheaper.

Whether you fit SS will perhaps depend on the fixing holes - ideally you want to use the same ones. The corrosion using alloy can be constrained by using duralec.
 
There was a theory in the 1970's that stanchion bases should be alloy, so as to break in case someone was thrown hard against them in heavy weather.

I always thought this was a bit of an excuse for then cheaper kit ( with no regard for future corrosion ), personally I like my guardrails & stanchions as strong as possible Ta very much, and I'll take my chances !
 
I'd be as much interested in the quality of the material as what the material is. Good quality cast alloy would be a much safer bet than some cheap Chinese stainless. Seajet is right, you dont want the stansions collapsing under your weight, they and the guard wires are there to keep you on the boat. I'd rather a few bruises than find myself having a swim.
 
MoodySabre said:
I'm at this point too. The Moody has alloy bases and stanchions. I assume they are alloy so that there are no problems as they bolted on to the alloy toe rail. However the pulpit and pushpit are stainless are similarly fixed. I've yet to try to get the old stanchions out of the bases - the results of that might decide which way I go. I can't think that it matters as SS are commonly used and look nice IMO.
Click to expand...

there should be a ptfe "wrap" between the stanchion & the base socket ;)
 
RobW said:
Hi folks,

I have come to the (costly) conclusion that replacement of both bases and stanchions is the best course of action all round.
Any ideas?
Rob
Click to expand...

Hi Rob
Yep had the same problem but with Stainless ones.
My best guess as to why they were fitted is that they came as a kit ie part of the stantion with the base at the time of build and cost.

One thing that's not mentioned is like me you really do not want to have to drill new holes to fit a differant design,so get an exact replacement design, the prices you have shown are about right (be lucky you did not want ones by Vetus !)

Getting the old ones off can also be good fun, clean off any old sealer and the bolt holes and reseal below the new base,we also added a dab below each bolt head just before we pulled it all down, we used sikaflex and had no problems since.

Mike
 
i am thinking of replacing the stantions my self but as i have some old / damaged stantions in the garage i think i will stay with the alloy ones.
the stainless ones bend quite easily and the titanium is to brittle and expensive so i am sticking with alloy
 
saltylegs said:
i am thinking of replacing the stantions my self but as i have some old / damaged stantions in the garage i think i will stay with the alloy ones.
the stainless ones bend quite easily and the titanium is to brittle and expensive so i am sticking with alloy
Click to expand...
I once owned a Trapper 500 with the known weak point of the alloy stanchions and the base mountings with insufficient under-deck padding with the resultant working, leaking and crazing of the deck grp. I was aware of this and had mentally noted to do something about it sometime but it all came to a head when I was thrown against one on a rough dark night and had it snap off leaving me hanging half overboard only restrained by the lifelines.

The solid alloy stanchion had broken cleanly a third of the way up, with no sign of corrosion or previous weakening.

I changed all stanchions to substantial stainless ones - and of course the bases to prevent dissimilar metal problems - at the same time tearing away the inner cabin liner to epoxy some hefty marine ply pads at the base fitting points. I would never have alloy stanchions on a boat again.
 
there is another option for the bases - mine are cast bronze and they + the stainless stanchions show no sign of corrosion after 33 years (but I shudder to think of the replacement cost!)
 
The deck on my boat has built in GRP sockets to take the stanchions.

When I built the boat I fabricated stanchions from SS tube and they are held in place by plastic brackets clamping to the toerail.

The result is no electrolisis and easy removal to for replacement.

I managed to bend one on a harbour ladder this summer but as I had made a couple of spares replacement only took a few minutes.

The standard alloy bases and stanchions seem to corode together in a very short time.

Iain
 
My first choice would be for carbon fibre stanchions ..... easy too look after and look good.

Alloy stanchions are also easy to look after and come a close 2nd.

Stainless stanchions add to the amount of cleaning and polishing work on the boat, and some designs of the bases can be really fiddly to polish.

Whichever you choose they should be good quality and designed for the job, and fitted with a good sized backing plate that is well bedded into the underdeck to ensure that the loads are distributed into the hull/deck structure.
 
My boat is 25 years old, I have owned her for 15 years. In that time I have changed all the stainless steel stanchions at least twice, several more than that, due to wear and loss of the plastic top caps on the original ones, then damage (mostly done by others) to the rest. The aluminium alloy bases are all original and apart from a little wear are perfectly OK. They are secured to the deck by stainless steel machine screws into aluminium plates laid up in the deck GRP, a recipe for corrosion if ever there was one. Despite this all remain removeable thanks to checking and resealing every five years or so.
 
Many thanks all for your helpful comments.

From looking around various websites I suspect I will be replacing like for like - it seems to be the only option to ensure the holes in the deck line up. I don't want to be filling and re-drilling! I guess the alloy has lasted 20 years of service so in all likelyhood it won't be me that will need to replace them next time!

Thanks again

Rob
 
I have found the stainless bolts used to hold an alloy stanchion in its alloy base very difficult to remove. My solution, which has worked well for several years now, is to drill through a 5mm hole and tap in a piece of 5mm rod, sticking out about 20mm either side. It can easily be tapped out, regardless of corrosion. You also get a useful "cleat" for light line, eg for fenders.

Tony MS
 
MoodySabre said:
I'm at this point too. The Moody has alloy bases and stanchions. I assume they are alloy so that there are no problems as they bolted on to the alloy toe rail. However the pulpit and pushpit are stainless are similarly fixed. I've yet to try to get the old stanchions out of the bases - the results of that might decide which way I go. I can't think that it matters as SS are commonly used and look nice IMO.
Click to expand...

I've done most of my bases and stanchions on my Moody - not an easy job, some take 10 minutes to remove, some take half a day! New bases should come with a plastic PTFE wrapround insert to protect the stanchion from the alloy base and of course the stainless bolts used to fix the stanchion to the toerail and through the deck. Also stainless split pins are used to fix the stanchion to the base. Use plenty of DURALAC to insulate the stainless from the alloy. I also insulated the stainless guard wires from the alloy stanchions with a nylon tube to prevent the wire wearing through the stanchion(which had happened on the old stanchions).
Having done all the stanchions and pushpit, I still have to do the pulpit on which one base has totally cracked in two - and I'm not looking forward to it...........
Stainless + Aluminium + Salt water = ELECTROLYSIS in a big way - WHY do manufacturers mix up metals like this??
If you need more info PM me.
 
Hi All,

Just to throw in my two penn'orth, I have just bought a Nicholson 30 MkII, which dates form the mid 70's. The boat was damaged in storm-force winds during the olympics after being put alongside another vessel. Most of the damage was to the toe rail, but a stanchion base on one side was pushed down through the side deck. The reason for this is that it was made of stainless steel, a far stiffer material than the cast aluminium alloy originally fitted by C&N. All of the bases on the port side failed, and this ultimately saved the boat from far greater damage. The alloy bases should be man enough to handle the force of a person being thrown against them, but the one-time impact of a person is totally different from the repeated impact from another vessel. I'm going to replace the broken bases with the original specification YS7157A bases to prevent future damage.

Best Regards,

David Seer.
 
"...than some cheap Chinese stainless"

Or some cheap British stainless.

Its not the country of origin that matters its the quality.
There's some excellent stainless made in China.
 
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