The perfect Passagemaker? II (building material)

Let us continue to find the perfect vessel within the given parameters, Peers.

To give you a brief overview what was the original SOR (part of it):

The vessel in question will be a motoryacht of about 23 to 25 meter Loa. A size I personally
call perfect for long ocean voyages with two people and no crew.
The yacht is planned for a couple with children and occasional friends.
She will provide a Maximum of 6 berths.
The boat will have transpacific range and a endurance of 90 days.

By so far we have found that (not surprising for me, but for some of us) the classical style obviously is the most popular one.
The contemporary design of one of the best selling boats in the market segment achieved just one single vote by so far!

The preferred style is the Gentlemans Motoryacht of the 60ies:



The second is the classical North Sea Trawler:



Go here to read the whole story if you have not been a follower of the thread:
The perfect Passagemaker? (style within this genre)


Now I would like to focus on the material of choice for the vessel/s.

What is, in your opinion, the perfect boat building material for a passagemaking vessel like the two shown above?

All views are equally welcome, the pro´s choice, derived from years of experience, as the novices or amateurs sheer gut feeling.
But please comment your choice, don´t throw just a few words in.

As we have seen on the former thread it is necessary to make it very clear what we are not talking!

No discussion about sailing boats, catamarans, earth movers and cable cars please!
I am asking for the material of choice to build the boats shown above, nothing else.

Those which don´t like the choice, stay out of here and open a thread to discuss different approaches, please.

Thank you for your much appreciated contribution.

Richard

edited:

For some reason I left out the more exotic choices like Monel and Titanium. The boat/s will most likely go in series production, too high the cost will not pay back.

[hoytedow]

My ancestors all crossed over on traditional wooden planked hulls. I will stick with them.

[RHP]

I voted GRP/Composite to reduce weight to a minimum whilst retaining strength to allow smaller, lighter and more efficient engines. The emphasis throughout would be economical weight saving to reduce power requirements.

[wardd]

copper nickel, was price mentioned?

[Brian@BNE]

This is a really hard choice for me. On one hand I like steel for a kinda go-anywhere hull with benefits of deep draft and low maintenance, if built and finished properly. But have an aluminum house on top. Take on high latitudes with confidence.

Then I think of all the low latitude places that are delightful, but need as shallow draft as possible. And thus turn to aluminum, which gets my vote. But as people like Mike Johns has commented many times, corrosion in aluminum can be terrifying. Still, by staying out of marinas (away from stray electrical currents), and building and installing electrical systems properly I think its manageable. It can be done without impacting on the styling, and costs could be pretty competitive even allowing for painting for cosmetic/styling considerations. Still OK in high latitudes with care?

[RHP]

Brian, seeing we're in a theoretical world, why dont you like GRP/Composite ?

[dskira]

I like steel, but round shape, built-down meaning plating all along on a straight keel with reverse garboard, and flare in the bow. Close spaces L shaped frames, no longitudinal. Hungry horse do not disturb me, quite the contrary. No longitudinal not water retention. Watertight compartment, four at least. Deck of steel sheathed in thick pine.
Superstructures of steel too, it's heavy but worth it. Superstructures sheathed with wood.
Inside bulwark sheathed of wood.

I voted for timber building. Same scheme as the steel.
Laminated frames, close spaced, double longitudinal planking, on laminated keel steam and stern.
Laminated beam and deck of combine tongue and groove and on top thick pine. (no ply)
All the superstructures of steel, sheathed with wood. Fashion plates of steel.
Watertight bulkhead of steel.

Both ship with canoe or cruiser stern, and as described above, built down of the planking and flare (pronounced) on the bow.
The two side plates joint at an angle at the stem, not in roundish manner, for both construction.

For the engine, well Richard you know what to put!

But that is my two cents

Daniel

[wardd]

I understand they have created carbon nanotube sheets of up to 4' x 8'

[Brian@BNE]

Originally Posted by RHP

Brian, seeing we're in a theoretical world, why dont you like GRP/Composite ?

Richard
My feeling (yes I don't actually know!) is that GRP/composite fails in a sneaky way. That is, you have an impact and see some damage but not realise how extensive it is. Another impact in same place equals major problem. The reason I say is that a 30ft GRP cat that I was part-owner of had this sequence. The bow holed (one side) and flooded. Yes the bulkheads and compartments did their job, and it just had its head down and tail in the air. It wasn't that far out, daylight, mild sea state and rescue easily effected. But scary, and I'm glad I wasn't on board at the time!

Now for our passagemaker, with proper scantling and layup I guess it should be OK, but the memories linger.

[TeddyDiver]

Alltough I'm a wood builder in this size I'd go with steel. In SOR there's anything limiting the material choices and ice classification wasn't mentioned, but it's allways good to have a hull that stands abuse and can be repaired anywhere. In this size you cannot take on the shore with the tide but steel is easy to weld uw..

" In this size you cannot take on the shore with the tide" - We do it all the time on vessels designed for this.

[philSweet]

I'm not sure I'd be comfortable calling a boat this size a world cruiser if it couldn't be built out of steel top to bottom. Build the first one that way. If you find yourself engaged in serial production, by all means start swapping in some composites. The point I'm trying to make is the hull form should be designed for this eventuality unless the SOR contains something that would make this impractical, and that seems unlikely given the 90 day endurance requirement. Of coarse, if the buyers of job 1 decided they wanted to spring for some lightweight composites, that would be just fine too.

[Willallison]

hmmm....
For me it would be a toss...
Steel, cause it's tough and can be reapaired easily and by just about anybody at a pinch.
Aluminium, cause I think the corrosion drama's can be overcome and it's tough, you don't have to paint it or polish it, and it's light.
GRP, cause it can be made tough, there's no corrosion / rust to worry about.

I'm yet to find a 3-sided coin, so without a particular reason to value one over another, I'll remain on the fence

[Eric Sponberg]

You are never going to find an answer, and I doubt a consensus. All materials have their own advantages and disadvantages, as already discussed above, and it really all depends on what the owner wants to do with the yacht. If it is cruising high latitudes where there is ice, then steel or aluminum are the best choices. If you are going to stay in the mid-low latitudes, composite or wood-epoxy would be appropriate. There are also the considerations of where are you going to build--who do you trust as the builder and what is his expertise? A good composites builder will build a better yacht than a lousy steel builder. Also, the quality of life on board has more to do with the mechanical and electrical systems than hull material, things that are completely independent of hull material. So many factors affect the decision that I cannot vote, because there is no single best choice.

Eric

Thank you all for your thoughts.

Will and Eric,

of course we will not find a consensus here, and that was not my intention.
I simply want to know what our members prefer when it comes to long voyages.
In my humble opinion such a vessel should be built for all latitudes, because requirements and owners change over the lifetime.

Brian,

I will not comment on any thoughts in deep. As I did not vote. In my opinion it is better not to show my personal preferences as the thread opener.

Regards
Richard