Are aluminium boats a liability?

[Neeves]

Looking a little sorry for herself nowadays. Hull not in the greatest condition (all imo).

Many yachts built in 1949 would have been scrapped by now and other yachts of the same vintage would look sad and tired, even people of that vintage look sad and tired. . 70 year old Yachts (and people) need some care and maintenance which is often expensive (health) insurance (or the NHS/Medicare) covers it for people, insurance for yachts does not cover maintenance.

Reading the posts - if you are a gifted amateur you can maintain and update an old, glass or wooden, yachts with average skills. Not so an aluminium yacht which I suspect needs deep pockets and specific and scarce skills to maintain.

Reverting to Geem's original post - aluminium does appear to be the material of choice for an expedition yacht, though many 'non-expedition' yachts have successfully completed the NW Passage, However unless you are going to higher latitudes, where ice might be a factor, other construction methods appear perfectly adequate, arguably better and cheaper than aluminium. Unless you are going to sail in ice - there are better materials than aluminium.

No-one on this thread has offered an advantage to using aluminium over the current cross section of alternative materials.

I do note Kukri's post where he compares the weight of identical designs in aluminium and fibreglass, where aluminium is astonishingly lighter, but I suspect if you built a Nicholson 55 now it could be lighter than one of the originals.

However it does raise the question to me - how do they maintain all the aluminium ferries, coastal patrol craft etc that are built from aluminium? Or do aluminium vessels become a liability when they are 20 years old (choose your own date), or older - unless you have very deep pockets (a characteristic of the owners of aluminium coastal patrol craft).

I have also noted the wear or corrosion issues mentioned by Bejansailor - which are 'simply' factors of maintenance and attention to detail. Sailing for us is meant to be a pleasure, not a constant round of minor, or major, maintenance issues (that will be catastrophic unless attended to quickly).

I hate to mention it - but how do they manage anchor lockers on aluminium vessels, lots of wiring (windlass), lots of dissimilar metals, windlass, steel chain (different alloys), stainless, anaerobic muds - and lots of constant salt water. The stainless nuts and bolts on an assembled Fortress anchor corrode into an immovable lump - unless protected with Duralac (no mention of this on the Fortress instructions).

I'll stick with a 'resin based' construction techniques, (Duralac and keep away from ice) - pending a more positive background to aluminium.

Jonathan

 

[Neeves]

Some of you, of more mature years (attentive and with good memories), may recall Aussie Bray who wrote for YM. Named Aussie Bray to distinguish him from the then editor Andrew Bray (I think that is correct). Aussie Bray's yacht was called Starship (I think) and he and family sailed the world, and this was the basis of many of his articles. His son continued the theme and his yacht is, or was called Teleport. There are a number of articles on Teleport and Chris Bray, simply google 'Bray' and 'NW Passage', and his wife one of which I link to - their transmitting of the NW Passage.

Sydney skipper youngest to sail the Northwest Passage

Starship was moored, out of sight, but not far from us and we lectured at the same events.

Jonathan

 

[Buck Turgidson]

This one appears to have survived quite well!
Morning Cloud IV

 

[Neeves]

This one appears to have survived quite well!
Morning Cloud IV

Both are exceptional

Morning Cloud IV Built in 1975

Pacha was built in 1968

For high latitude sailing:

Novak's Pelagics are aluminium (and large at 77'). The first was launched around 2017/8 ?. as was Starzinger's custom built 47' Hawk, Van De Stadt around the year 2000.

J

 

[Neeves]

So far this is just a flash in the pan, but the idea was a success. You simply need courage and, maybe, an old slate mine.

Talking of exceptional aluminium yachts, this one is 'one of a kind' and discussed here, YBW, recently and another interesting story - local to me. As far as I know - no high latitude sailing - just a run of the mill racing yacht . You need to read most of the thread - its not long, no mention of anchors.

Marvel and enjoy

Gelignite 35 foot aluminium yacht whereabouts

This is real lateral thinking. Take a sheet of Aluminium and a well built mould and you can produce identical hulls in a flash. It must be almost the quickest production technique you can think of - a lot of bang for your buck.



Jonathan

 

[Kelpie]

Explosive formation is used for rocket engine combustion chambers. But they tend to be inherently a bit more explosion proof than a yacht hull.

 

[ean_p]

There is no perfect boat building material, but aluminium is hard to beat.

Cupro Nickel goes a long way.....there was a yacht hull been fitted out in the club yard in Grimsby (UK) some 10 -15 years ago, with if memory serves stainless top sides, though may be wrong on the latter...! I understand there are quite a few working craft on the south coast US too with cupronickel hulls

 

[geem]

With regard to weight of aluminium compared to grp. My pal designs and builds skiffs. They can be built in foam core and glass or aluminium. The weight of the finished boat is the same.
I don't think weight is an advantage with aluminium. You can build a lightweight aluminium hull that will likely be very different to one built to deal with ice. You can build lightweight foam core composite grp hulls that are light and stiff or heavy solid laminate hulls that are cheap and less stiff. You don't choose aluminium for weight saving but you might choose it as a material for a one off lightweight racing boat simply because you don't need to go to the expense of building a mould. Aluminium as a material has been around for a long time. GRP for boat construction since the 60s. At the rate a lot of grp boats are going I wouldn't surprise me to see well built hulls still going at 100 years old. A friend campaigns a grp Cal 40 on the race circuit. Boat built in the 60s. It's in as new condition

 

[noelex]

Cupro Nickel goes a long way.....there was a yacht hull been fitted out in the club yard in Grimsby (UK) some 10 -15 years ago, with if memory serves stainless top sides, though may be wrong on the latter...! I understand there are quite a few working craft on the south coast US too with cupronickel hulls

Titanium has also been used for a couple of yacht hulls. It does not have the antifouling properties of cupro-nickel, but it has great strength to weight ratio. The difficulty is welding the titanium reliably.

 

[noelex]

With regard to weight of aluminium compared to grp. My pal designs and builds skiffs. They can be built in foam core and glass or aluminium. The weight of the finished boat is the same.
I don't think weight is an advantage with aluminium. You can build a lightweight aluminium hull that will likely be very different to one built to deal with ice. You can build lightweight foam core composite grp hulls that are light and stiff or heavy solid laminate hulls that are cheap and less stiff. You don't choose aluminium for weight saving but you might choose it as a material for a one off lightweight racing boat simply because you don't need to go to the expense of building a mould. Aluminium as a material has been around for a long time. GRP for boat construction since the 60s. At the rate a lot of grp boats are going I wouldn't surprise me to see well built hulls still going at 100 years old. A friend campaigns a grp Cal 40 on the race circuit. Boat built in the 60s. It's in as new condition

Aluminium hull construction is generally regarded considerably lighter than solid glass polyester hulls and very slightly lighter than foam core polyester glass. The more exotic foam core fibreglass layups, for example incorporating E-glass and Epoxy resin, will generally be similar or slightly lighter than aluminium construction and incorporating carbon fibre etc can produce a much lighter hull than is possible with aluminium construction.

This weight scale changes for small vessels such as skiffs. It is not practical to weld very thin aluminium, forcing the use of thicker plate than would be required for strength alone. This problem disappears with larger vessels. But smaller vessels can still sometimes be lighter in aluminium. Many will be familiar with the aluminium or fibreglass hull choice for RIBs. The aluminium version is invariably lighter and more puncture resistant, but also more expensive.

It should also be remembered that some aluminium boats are constructed with thicker than required materials and more framing to withstand adverse conditions such as contact with ice, so it does not necessarily follow that an aluminium yacht will have a light hull.

 

[geem]

It should also be remembered that some aluminium boats are constructed with thicker than required materials and more framing to withstand adverse conditions such as contact with ice, so it does not necessarily follow that an aluminium yacht will have a light hull.

I think that's what I said

 

[Kelpie]

The ~6m workboat I used to use had something like 6mm alu plate. Its younger sister was built with thinner plate to save money, and had to be retired after only a few decades due to fatigue cracks. A false economy.

 

[Tintin]

Aren’t marinas the challenge for alloy?



All those differing keel materials , steel pilings and wobbly stray electrics in proximity ?

An isolation transformer solves the problem with shore power.

 

[Neeves]

noelex said:
There is no perfect boat building material, but aluminium is hard to beat.

Or

There are many perfect boat building materials - it depends on the objectives. Runabouts, production yachts, sailing skiffs, offshore patrol boats, ferries and expedition yachts all offer different requirements and the materials used have tended to polarise for each application.

If aluminium, or carbon fibre reinforced resins were the perfect material we should see more use of these materials. Popularity is often financially driven - nothing to do with technical characteristics (though technical characteristics, ease of use of material or of the vessel when made, may drive up prices/costs).

I confess, probably biased (and parsimonious), - I have not seen a compelling argument for aluminium. Maybe we need a few French or Dutch members.

Jonathan

 

[geem]

Does anybody have an aluminium steering pedestal that is corroded? My Whitlock pedestal corrodes for fun. Every one I have seen on an older boat has bubbling paint. We had our corrosion cut out and new sections welded in but keeping paint on it is impossible. Tried alachrome pre-treatment. That didn't work. Currently epoxied and two pack paint finish. That's bubbling again. I have added an earth wire to it about a year ago connected to an anode to see if stray currents are the problem. It seems better but not cured. We replaced the aluminium toerail in 2021. Also the genoa tracks due to corrosion. I can't imagine the hassle with an old all aluminium boat.

 

[noelex]

The best thing you could do for your steering pedestal and toe rail would be to isolate all the dissimilar metals as much as possible. Duralac or Tefgel on all the stainless bolts. Isolate all the metal steering gear from the aluminium using plastic bushings etc. Finally make sure there is not any electrical connection to the pedestal from either the positive or negative supply.

The problem with the the steering pedestal, toe rail, sail drives and other aluminium parts used on fibreglass boats is a large amount of dissimilar metals (in relation to the mass of aluminium used) combine with using 6 series aluminium alloys.

Aluminium boats have a much greater mass of aluminium and are built from the far more corrosion resistant 5 series aluminium alloys.

Getting paint to stick to aluminium is a problem, but the 5 series aluminium alloys do not require any paint for corrosion protection so the better aluminium boats have very little paint apart from antifouling which needs periodic replacement anyway.

 

[Kelpie]

Our pedestal is 45yrs old and no sign of corrosion.

 

[Kukri]

47 years old; perfect!


(did I mention that it was blasted and powder coated by Sims Marine* when they rebuilt the steering gear?)

* unabashed “plug” for an excellent firm.

 

[Tranona]

connected to an anode

An anode will not do anything as the pedestal is not in the water.

 

[geem]

An anode will not do anything as the pedestal is not in the water.

When you sail a lot it gets plenty of spray over it. I think that has been the issue over the last few years. We have done pretty high mileage and some bumpy passages. Lots of salt water flying about. We now rinse the pedestal with fresh water when we arrive. Even so, still some bubbling paint.

Edit: thinking about it, the boats that have bubbling paint on their pedestals are used similar to us. They have done several Atlantic crossings. They get constant coating of salt water. If the aluminium was kept salt free and dry and doubt it would corrode. Ours always corrodes at the base. This is where we had corroded metal cut out and replaced with new