A Catamaran Question

[cwjohm]

Here you go.

Phaedo after the ARC: Shifting into Cruising Mode | Sail Magazine

An interview with an owner who runs his gunboat in both cruising and sailing mode.

Typically 240m per day in cruising mode.

Compare this to Gordon who is in a Helia and running around 180-200m per day crossing the Atlantic as we speak.

[cwjohm]

Phaedo cost around $4 mill so that's around about $50K extra for every average nautical mile performance over 180nm per day.

Mind you there are a few boats for around $2.5 mill that could do this, so prolly only need around $25K extra for every average nautical mile.

This is only on the cost of the boat - running costs are extra but whose counting.

[weavis]

SO we are all agreed then...... its a difficult thing to do.

However $2 million plus brings the goal a little closer...

[belizesailor]

Originally Posted by weavis

SO we are all agreed then...... its a difficult thing to do.

However $2 million plus brings the goal a little closer...

And I think alludes to another measure of performance which would be worthwhile for comparison, and that is dollars/knot. Easy enough to compute for max speed or even calibrate to polars. The hypothetical "average" would be more challenging.

If the $2M got you your hypothetical average of 15 knots then that's over $133K per knot!

Compare those $/knot to more typical cruising cats and the trend of that curve is awfully step.

So the question becomes, how much are you willing to pay per knot?

[colemj]

Originally Posted by weavis

However $2 million plus brings the goal a little closer...

Well, now you have completely changed your original parameters of less money and smaller size. Yes, 2 mill brings it closer in a large boat, but 2 million will not get you a 36-40' boat in cruising trim that averages 15kts. Even if it got close, I doubt you personally would be able to physically take that speed in that size of boat in average cruising conditions.

At least I wouldn't be able to...

Mark

[cwjohm]

Gunboat G4 will get close. Not exactly the epitome of comfort though.

[valhalla360]

Originally Posted by weavis

Im thinking of a cruising Cat.

I understand length and fine entry is a help for attaining speed. I need to talk with Minaret and see if a 15 knot average is possible with a 40 footer built out of GRP, in a cruising configuration......

I don't think you understand. Length and beam to length ratios are the primary drivers of speed.

You can get marginal improvements by going with expensive high tech materials but you won't take an 8kt boat and make it a 15kt boat by just swapping out the materials (just relative no claims about average speed).

As someone else alluded to the 1.3 in the hull speed formula is not really a constant. It is related to the length/beam ratio.

Gunboats and other really high performance boats achieve higher speeds get some benefit from light weight high tech materials but the bulk is based on putting a 40' boats accommodations in a 50' boat.

If you start with a 40' boat, in order to keep the weight down enough to get the performance of a 50' boat, you wind up with the accommodations of a 25' boat. Remember gunboats and similar high performance boats already use the expensive light weight materials.

[Sand crab]

The brand new Maine Cat 38 is close to your specs but with an average claimed speed of 10 knots (so slow). All vinylester construction, 8100 lbs lightship, and only $337.000. Plus the standard MC enclosed helm, self tacking jib with curved track, daggerboards and an 11.4 B/L ratio. They are fully customized to your specs and have a proven track record established for ultra high quality cats. Check out the details.
Maine Cat 38 - Maine Cat Catamarans

[Steamer]

Originally Posted by weavis

SO we are all agreed then...... its a difficult thing to do.
However $2 million plus brings the goal a little closer...

Well. To have best speed results one needs proper boat and proper weather conditions. If GB60 is what we look at first and compare with, then under equal weather conditions:

-cruising 60-ft cat, 9 tons empty (main 118m2 + solent 56m2 self-tacking) @ USD 2,400,000 two hulls built by now and sailing - will easily bit GB60.

-smaller 57-ft cruiser - 12 tons empty (maiin 109m2 + 63m2 self-tacking jib) will still bit GB60, price inclusive (USD 1,800,000). Hull No.1 is under construction.

Take Your choice!

[smj]

Originally Posted by Sand crab

The brand new Maine Cat 38 is close to your specs but with an average claimed speed of 10 knots (so slow). All vinylester construction, 8100 lbs lightship, and only $337.000. Plus the standard MC enclosed helm, self tacking jib with curved track, daggerboards and an 11.4 B/L ratio. They are fully customized to your specs and have a proven track record established for ultra high quality cats. Check out the details.
Maine Cat 38 - Maine Cat Catamarans

I really like the Maine Cats but can see no way that it will average 10kts. Maybe 7 which wouldn't be a bad average for a 38' cat.

[smj]

Maybe the Sig 45 would be as close as you could get.
http://youtu.be/NbzvmH0NKWo


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[Canibul]

Originally Posted by smj

I really like the Maine Cats but can see no way that it will average 10kts. Maybe 7 which wouldn't be a bad average for a 38' cat.

I like them too. Where we live and sail, the open concept works really well. Enclosed salons, well, they work too but we could live without one. Love the draft options of the MC 38. I like the big one, too.

What I think might be something I wouldn't like about that owners layout is the single head for the whole boat, and everyone has to go through the owners suite to get to it. Could get a bit hectic with a full boat of five adults and my Texas chili. I think this should be a two cabin boat.

Or Maybe we could install a Nature's Head on the sugar scoop for guests. Call it the Sir Richard Branson Necker Island mod.

[belizesailor]

I like the open deck arrangement of the MC's too and some of Wharrams larger designs.

[weavis]

Originally Posted by Canibul

I like them too. Where we live and sail, the open concept works really well. Enclosed salons, well, they work too but we could live without one. Love the draft options of the MC 38. I like the big one, too.

What I think might be something I wouldn't like about that owners layout is the single head for the whole boat, and everyone has to go through the owners suite to get to it. Could get a bit hectic with a full boat of five adults and my Texas chili. I think this should be a two cabin boat.

Or Maybe we could install a Nature's Head on the sugar scoop for guests. Call it the Sir Richard Branson Necker Island mod.

Yep. Im not a lover of a single head where you have to either go through it to get to a cabin or go through a cabin to get to the head. Kinda poor design.

[colemj]

Originally Posted by weavis

Yep. Im not a lover of a single head where you have to either go through it to get to a cabin or go through a cabin to get to the head. Kinda poor design.

On a 36-40' performance boat, with hull beam <5' (I think this one is <4'), there is little choice in the design. One either uses an entire end of a hull for a head, or uses a walk-through design, or pushes into the bridgedeck clearance in an unnatural way.

Mark