Bestevaer 49

[Kelpie]

Congratulations! Thanks for the updates of a fascinating project.
If you're ever up this part of the world I would love a wee nosy aboard

 

[Neeves]

If anything I might have suggested alloy yachts are less favoured, than steel - but the choices are often dictated by finances and an ability to invest the time and effort into a custom built yacht. I might not have said so Roger but I do admire your yacht, and I'm a plastic fantastic multi owner, I admire the work and time you, personally, have invested. I simply could not achieve what you have done and much of your build has been your ideas and your work - all credit to you. You have only given us snippets of your build.


Noelex, the thread is too long to wade back -

But what have you used for antifouling?

She looks absolutely gorgeous and a credit to the builders. She looks a serious yacht, good for anywhere and should last for decades.

Congratulations.

Jonathan

 

[rogerthebodger]

It’s one-dimensional zealots that are not favoured, not steel boats

I think everyone has always been very complimentary about yours, have they not?

Pete

Yes I do get that and I do also think Brent is also one dimensional as you say and does do a disservice to other steel boat owners.

Brent is OTT but does have have a great deal of knowledge in steel boat construction and protection, which dets lost due to his " one dimensional" view. the problem is soughting out the good info from is one dimensional views.

And thanks very much being complimentary about my boat.

Also thanks to Neeves for you kind comments.

Metal boats are in my view a lot more labour intensive to build that GRP boats but both have their advantages and disadvantages. It was also why ferro boats went out of fashion as the hull build was cheep as own or low skill labour was used but the fitting out is very much the same. Steel and aluminium are very much the same except in my view more skill is required to build a steel of aluminium hull but the fitting is the same. Customisation and type of use becomes factors.

I can remember when Colvic boats started in 1962 yes 1962 and became very popular as the hull/deck construction was done at a lower cost and faster that ferro, steel or wood. No aluminium was being used as the welding technology for aluminum was not really available in my early days.

Time moves on.

For the record my hull/deck was build in the late 1970's and I picked it up modified and finished as a lot of home builds were started but not finished it only pig headed people like me who finish then.

 

[GHA]

........ However, Dyneema is more effected by UV and chafe so some care is needed................
.......
.....I think for most cruising boats uncoated stainless wire is probably the sensible choice, but for a weight sensitive boat like a cat or an aluminium boat where it helpful to reduce the amount of stainless then Dyneema while more expensive is the better choice.

I tried some short strops of marlow D12 max as part of mooring warps over a few months in winter in a marina in Dartmouth, low pressure systems going over every few days with the boat often getting severely thrown about. The dyneema went through the fairleads and on one spring rested against the edge of a bit of a stainless angle.

Amazing stuff, even with BIG forces of a heavy steel boat getting thrown around the dyneema was hardly chafed at all. Dyneema is pretty robust stuff to start with, plus whatever marlows anti chafe coating is, it certainly works.


Big fan of dyneema lifelines now, just nicer on the hands, better for hanging out the washing,...

Doing the splices yourself the cost differences might not be much more compared to new wire & swaging.

 

[npf1]

Noelex - can you please elaborate on the arrangement at the bottom end of the backstay? Have you gone for a single hydraulic cylinder, that then tensions some type of line (or wire?) to create the split?

Thanks in advance

 

[noelex]

But what have you used for antifouling?

Trilux 33

 

[noelex]

Noelex - can you please elaborate on the arrangement at the bottom end of the backstay? Have you gone for a single hydraulic cylinder, that then tensions some type of line (or wire?) to create the split?

Thanks in advance

There is a large stainless steel block dividing the backstay. A divided backstay is necessary because of the drop down swim platform.
The backstay tensioner is a mechanical Selden unit.

 

[Neeves]

Trilux 33

Are there documented technical reasons for not isolating the hull, with a barrier coat, and then coating with a copper based AF?

 

[npf1]

There is a large stainless steel block dividing the backstay. A divided backstay is necessary because of the drop down swim platform.
The backstay tensioner is a mechanical Selden unit.

Thank you

 

[Champagne Murphy]

Noelex, haven’t seen anything about the power unit (aka engine).

 

[Neeves]

Noelex, haven’t seen anything about the power unit (aka engine).

but more often called sails?

Jonathan

 

[noelex]

Are there documented technical reasons for not isolating the hull, with a barrier coat, and then coating with a copper based AF?

Yes, this is sometimes done, but I would not recommend the practice. Antifouling designed for aluminium hulls like Trilux 33 applied on top of an epoxy barrier coat (we specified 5 coats of Interprotect) is better for an aluminium hull.

 

[Neeves]

Yes, this is sometimes done, but I would not recommend the practice. Antifouling designed for aluminium hulls like Trilux 33 applied on top of an epoxy barrier coat (we specified 5 coats of Interprotect) is better for an aluminium hull.

If this is sometimes done are there results that show that a copper based AF (on top of Interprotect, however many coats are needed) causes corrosion (as in which case I would think the sometimes becomes never ) - but if it is sometimes done and there are no cases of corrosion why do you recommend against it?

If there are no negative reports, when done correctly, then using a copper based AF on an alloy sail drive - suddenly becomes an option. I am aware that Jotun conducted, or reported on, some successful trials with a copper based AF on alloy - but I have not seen a subsequent long term assessment. There are other examples - but I don't have sufficient information to pass comment - but they do raise questions or options.

Our experience with Trilux 33 on a sail drive in Sydney suggest you might expect a maximum of 6 months life and less if you cannot swim and wipe down.

Jonathan

 

[noelex]

Our experience with Trilux 33 on a sail drive in Sydney suggest you might expect a maximum of 6 months life and less if you cannot swim and wipe down.

Antifouling performance varies significantly with location, as well as factors such as how the boat is used and how the paint was applied, so it hard to generalise, but while Trilux33 is not as good as the best copper antifoulings, overall it is not as bad as your quote implies. We have used Trixlux 33 for the last 10 years of full time cruising and haul outs are about every two years.

While sail drives have an aluminium casing they are different to aluminium hulls. The aluminium material is not the same as used in hull plating and it is often not appreciated how dramatically the properties of aluminium vary depending on its composition. The saildrive contains dissimilar metals and the hull is typically surrounded by copper based antifouling, stainless and bronze. All this would be a corrosion problem even without considering the antifouling used on the saildrive itself, but the manufacturers rely on anodes and an effective paint scheme for corrosion protection.

Aluminium hulls are quite different. The 5 series aluminium used in the hull plating on its own is almost corrosion free even withoult any protective paint scheme. The amount of disimilar metal immersed in the electrolite such as the prop and shaft is quite small in relation to the mass of aluminium in the hull. The hull does not need any anodes (although these are sometimes fitted) or paint (apart from antifouling function) and the corrosion protection is fundamentally from the properties of the aluminium.

So sail drives and aluminium hulls are not directly comparable. Personally, I would not take the risk and put copper based antifouling on a sail drive no matter what barrier coat was used. A scrape from hitting debris can always expose raw aluminium. The presence of a large amount of copper is not good in this situation and the owner would not necessarily be aware until the next haul out. However, I have always selected boats with a shaft drive so I do not have any practical experience of maintaining a sail drive.

 

[noelex]

Noelex, haven’t seen anything about the power unit (aka engine).

The engine is a Yanmar 4JH4TE. It is a shaft drive with an Aquadrive CV joint and a Brunton Autoprop.

We had to order the engine early in order to fit the last of the non common rail models.

 

[Champagne Murphy]

The engine is a Yanmar 4JH4TE. It is a shaft drive with an Aquadrive CV joint and a Brunton Autoprop.

We had to order the engine early in order to fit the last of the non common rail models.

Good move. At least you can service it easily

 

[noelex]

The interior cushions have been delivered. We talked to upholsterer HJF De Koning and picked the leather almost three years ago. They have done a wonderful job of interpreting our wishes and the navy combines nicely with the warmth of Bubinga and the simple white of the walls.

The dining room table is still to be installed.

 

[Ric]

Antifouling performance varies significantly with location, as well as factors such as how the boat is used and how the paint was applied, so it hard to generalise, but while Trilux33 is not as good as the best copper antifoulings, overall it is not as bad as your quote implies. We have used Trixlux 33 for the last 10 years of full time cruising and haul outs are about every two years.


While sail drives have an aluminium casing they are different to aluminium hulls. The aluminium material is not the same as used in hull plating and it is often not appreciated how dramatically the properties of aluminium vary depending on its composition. The saildrive contains dissimilar metals and the hull is typically surrounded by copper based antifouling, stainless and bronze. All this would be a corrosion problem even without considering the antifouling used on the saildrive itself, but the manufacturers rely on anodes and an effective paint scheme for corrosion protection.

Aluminium hulls are quite different. The 5 series aluminium used in the hull plating on its own is almost corrosion free even withoult any protective paint scheme. The amount of disimilar metal immersed in the electrolite such as the prop and shaft is quite small in relation to the mass of aluminium in the hull. The hull does not need any anodes (although these are sometimes fitted) or paint (apart from antifouling function) and the corrosion protection is fundamentally from the properties of the aluminium.

So sail drives and aluminium hulls are not directly comparable. Personally, I would not take the risk and put copper based antifouling on a sail drive no matter what barrier coat was used. A scrape from hitting debris can always expose raw aluminium. The presence of a large amount of copper is not good in this situation and the owner would not necessarily be aware until the next haul out. However, I have always selected boats with a shaft drive so I do not have any practical experience of maintaining a sail drive.

The coppercoat website argues that it is safe to put coppercoat on an aluminium hull over an epoxy barrier. It also implies that they have clients who have taken the plunge. However, I have never come across any reference on the internet from the owner of a coppercoated aluminium boat.

I have coppercoat on my current boat and would certainly want it on a live-aboard boat. The idea appeals of being able to periodically clean off growth by diving and the occasional pressure -wash while dried out (on the likes of a Boreal) rather than being tied to lifting out in a yard, sourcing all the equipment etc.

 

[Neeves]

I do have a report from an owner of an alloy yacht who, against the advice of Noelex, has CopperCoated his alloy yacht and is on his way for Europe to Oz. He is now in Thailand. He had an unfortunate encounter with some coral which took the coating back to bare metal. He has checked and there is no sign of any corrosion. Coating sail drives, alloy, and props is apparently commonplace in America - and if it did not work the legal profession would have made a fortune.

I think there is a lot of misinformation about, but that seems quite normal.

The key is having a decent barrier coat (and as Noelex applied 6 coats of Interprotect that does not seem out of the way). The fact a sail drive may be a different alloy to 5083 seems to be another red herring as with a decent barrier coat it will be no different to a more corrosion resistant alloy.

I have run tests on 7075 alloy (a higher tensile alloy) which is said by some to have poor corrosion resistance. I have had it as a shank on my alloy Anchor Right Excel (one of my 3 alloy primary anchors - the others being Spade and Fortress) sitting on my bow roller and in regular use and it is suffering no corrosion - its been there for 5 years now. I wonder howe long I need to wait for the dire predictions to come true. I tested 5083 against 7075 in an accelerated environment - both alloys corroded, the 7075 faster, or worse, than the 5083. So, yes, it is less corrosion resistant than 5083 but in real life it works.

So the poor corrosion resistance of 7075, compared with 5083, is correct - but not relevant if used with care (as one must do with 5083).

There is a lot of misinformation about based purely on hearsay. Actual use seems to contradict the established mantra.

In theory, practice and theory are the same - in practice they are different.

I am slowly collating information on the use of copper based AF on alloy and the characteristics of alloys that might be useful in the marine application. I'll be evaluating barrier coats - when I have sufficient and I am happy with the data - I'll publish. In the meantime - keep an open mind.

Jonathan

 

[npf1]

Whether or not CopperCoat is compatible, resale needs to be considered also. There’s an aluminium boat in North Wales, that been for sale for donkeys, that had been Coppercoated. I spoke to the broker about it last year and he said the owner was planning to remove the CopperCoat over the winter. One can only assume that they felt it was an impediment to a sale.