What boatspeed should I expect, as a percentage of True wind?

[GRIT]

I'd like to call BS on this quote, but I'm not experienced enough to really say. I know GRIT can't match these numbers. We can do 10 in 15, but not at 47 TWA.

"The upwind performance boost of daggerboards is impressive. ‘The best VMG is usually around 48-53°,’ he says. ‘An Outremer will beat a good racer-cruiser monohull upwind in good conditions, with a target speed upwind of 10kts at 47° TWA in a true wind of 15kts.’ Few other cats can do that."

47 TWA, and making 66% of windspeed? That's got to be 33 AWA or less, and making 66% of windspeed. I think we'd be lucky to make 50% at that angle.

Is this possible?

Here's a link to the entire "sales pitch". https://yachtracing.life/outremer-the-yachtsmans-yacht/

Cheers.
Paul.

[jmh2002]

Off the top of my head I guess a few things in the article need clarifying first:

- 'In good conditions'. Does he mean in flat water?

- The 4X and 5X models were referenced. They have rotating masts.

- These French multihull guys normally sail with the boat pretty stripped out.

It all adds up.

Outremer suggests a 10-15% performance increase from the rotating mast alone.

Here's an article and a video discussing it.



https://sailwildling.com/2014/09/13/...rotating-mast/

https://www.youtube.com/watch?v=SfCMJ-rbpeE

And for fun, not sure if you've seen this old video of the Great Circle crew onboard the 5X BioTrek 'delivering' the boat from La Grande Motte to the Cannes. Hammer down... (not upwind though).

https://www.youtube.com/watch?v=VSRZxz2HGXw

[GRIT]

The 4x does have 14m2 more sail area than we do. Our jib is tiny. Maybe if we had a schreecher, sheeted inside the shrouds... I've measured that we can have a 55m2 schreecher sheeted to the jib tracks. Maybe it is possible...

Here's what we can do now, in similar wind speeds.

https://www.youtube.com/watch?v=7JIwFnT_xMA

As you can see, we make about 50% of windspeed. Maybe another 15m2 of sail area would get us up there. Anybody here able to pull off 66% of windspeed at 47 TWA?

Thanks Jmh2002, I can see that it might not be BS, as they have much more sail area than we do, and far more experience too!

Cheers.
Paul.

[jmh2002]

The 4X and 5X has quite a powerful (rotating) rig. Maybe you are still underpowered a bit, especially in cruising trim / payload?

If I remember correctly @fxykty was previously proposing a big headsail to be sheeted inside the shrouds to complement the self tacker on his earlier generation O55L.

I'm not sure if that eventuated, hopefully he will chime in here.

[GRIT]

Yes, I think we're still underpowered for most wind angles. We're not bad between 100 and 130 TWA, with the Code 0. But we need a screecher for closer to the wind, and an Asym for further downwind. We were going to get an asym this fall, but our travel timing isn't going to work. The screecher will be a laminated sail, but the Asym will be nylon. If the Code zero gives out, due to abuse , I'd like to replace that with a more modern material (ours is nylon).

But still, that guy claims 10 knots in 15, at 47 TWA, that's going to be nearer 30 awa than 35 awa. I don't know if I'll ever manage that. But reading articles like that one is what get's me shopping for sails...

Cheers.
Paul.

PS, we're slightly lighter than the 4x is, our lightship displacement is about 7.8 tonnes.

[jmh2002]

I see that the 'performance' bug is starting to bite now that the potential of your boat is starting to reveal itself in reality instead of just in theory...

[GRIT]

Maybe just a little...

Paul.

[Chotu]

Still sitting on the bench, but hopeful to get to try these things this spring, I’m wondering about mast height.

They have the rotating mast on this Outremer. That’s known to add 10-15% to any boat. They also have a bit more sail area.

What’s the mast height here we are talking about? I’m getting mine together this winter and it’s already too short. I’m putting an extension at the base of it to get the extra length to match Grit’s, but is that about the same length as the Outremer mast?

Or... is that sail area due to their code 0 we are talking about?

I won’t have a nice Square top main at first. I’ll just be running the old sails that came with the rig. Those are a triangle top main and blade jib. Even more sail area reduction.

I may be running junk sails for the first season, but I do want to get the foundation right so I can add the Square top main and the necessary headsails as needed.

How does this Outremer’s mast height compare?

I do see the Outremer is a good bit heavier than my boat. Plenty more boat below the waterline. But the sail area looks huge.

[Sand crab]

I can't find the actual mast length but the stats for the 4X are:
Length48 ft
Beam 23.3 ft
Draught 3.3/ 6.6 ft
Air draught 66.9 ft
Displacement 8.2/ 11.1 t

Sail plan
- Mainsail 69m2
- Genoa 55m2
- Gennaker 115m2 (option)
- Spinnaker 150 m2 (option)

And the 5X:
Length60 ft
Beam 27.7 ft
Draught 3.9/ 8.7 ft
Air draught 86.7 ft
Displacement 14.8/ 20 t

Sailplan
- Mainsail 125m2
- Selftacking jib 74m2
- Gennaker 190m2 (option)
- Spinnaker 257 m2 (option)

Both boats have cabin stepped masts as opposed to bridge deck stepped. The 4x is the same hull as the 45 but it's lighter with bigger sails so much faster. None of the Outremers have protected helms but a Youtuber that has one on an O51. He did mention that the boom had to be raised for that but I don't know the details.


https://catamaran-outremer.com/en/ca...s/outremer-5x/
https://catamaran-outremer.com/en/ca...s/outremer-4x/

[Chotu]

Thank you for that data, Sand crab. That’s a great starting point for comparison.

I will most certainly be referring back to that post this winter planning things out.

[JustMurph]

Originally Posted by GRIT

The 4x does have 14m2 more sail area than we do. Our jib is tiny. Maybe if we had a schreecher, sheeted inside the shrouds... I've measured that we can have a 55m2 schreecher sheeted to the jib tracks. Maybe it is possible...

Here's what we can do now, in similar wind speeds.

As you can see, we make about 50% of windspeed. Maybe another 15m2 of sail area would get us up there. Anybody here able to pull off 66% of windspeed at 47 TWA?

Thanks Jmh2002, I can see that it might not be BS, as they have much more sail area than we do, and far more experience too!

Cheers.
Paul.

Here's another data point. I can't point quite that high with my crappy main.....33º AWA is about it......but at 33º AWA (50º TWA) in 15 knots TWS my Mumby will sit on a solid 8.5 knots in smooth waters. I think that extra 3º does make a big difference to speed, as does the 48m genoa.

[GRIT]

Thanks for that JustMurph.

It's true that 3 degrees can make quite a difference, especially when pinching like that.

I look forward to getting some extra sail area up front, for going close to the wind. Then I'll have a better idea. I'll also keep watch for a 15 knot wind, so I can try to replicate what they're saying. I don't recall sailing at exactly those angles and windspeeds.

It struck me as unlikely, at first reading, but I think the responses here are convincing me that it's possible.

I should note, that in my video, the boards weren't all the way down. I had another 18 inches or so I could have dropped down.

The Outremer hulls must be pretty slim too, to get those results.

Cheers.
Paul.

[smj]

The Outremer 4x has a lwl/bh of 11.79 so slippery but maybe not racing fast? Is your Kurt Hughes the 48’ cruising model?

[GRIT]

Thanks for that SMJ.

No, we're not the 48.

We had Kurt make us our own design, from several of his plans. (the 45, the performance cruising 49, and the outsider 48)

We started with the 45 model (I read the Hull beam to length ratio was 10.9, but I think it was more like 11.2 ish) and had him stretch the hulls 4 feet, without widening them (which gives us about 12:1 hull beam to length ratio) We then had him shorten the bridgedeck by about 6 feet (using the mast beam from the outsider 48), lengthen the cockpit by 18 inches, we used the rudders from the performance 49, had him design a carbon bow beam, move the engines forward 6 feet, and several other mods to suite our preferences. We then nearly doubled the sail area of the stock 45 (which used to advertise as having 480 mainsail and 220 jib, we have 800 mainsail and 400 jib).

Kurt's retired our model, and has a new 45 with a bustle in the hulls, to widen them above the waterline. When asked about our boat, he calls it a "heavily modified" 45. He doesn't like the front cockpit, but likes the inside steering... We called it a 49x on our permitting papers. It actually measures 49.6 feet, not including the sprit.

We launched at just over 16000 lbs, without the mast but with more than 300l of fuel and a bunch of building supplies.

Don't get me started talking about our specific boat, or it'll never end.

Cheers.
Paul.

[Chotu]

Mine is much the same, with different modifications.

Instead of the station to station elongation, I added a couple bits to each end to counteract some problems I’d experienced before with boats and seen in his designs specifically.

First, I went right ahead and added about a foot and a half to the sterns, creating a slower rocker back there. I had seen nearly all catamarans suffer from inefficient squat back there. It worked nicely and I don’t get any squat at 8 knots under power.

Second, I ADDED reverse bows to the boat, which added another few feet on the bows at the waterline, tapering back to designed LOA at the deck level.

I did not change engine placement, as I opted for outboards, but did add my own design for outboard wells which puts the outboard leg precisely where the sail drive leg is in the plans. Result is the same handling as a sail drive with outboards.

I kept the oddly long bridge deck Grit shortened. I had thought I needed the interior room.

Sail area should be close to the same as Grit when I get the real sails on later. For now, running some old sails that came with my rig while the boat is still under construction.

Bow tube will be aluminum on mine. Need to add a sprit and Code 0 and Asymmetrical hopefully later.

I had initially had the front cockpit as well, but changed that and opted for a “sail control table” in the salon so all sailing is to be done completely indoors. Helm is indoors too. I’ve had too many years in the elements.

Projects for the winter are to get the rig on, fix some slack in my steering that is causing the auto pilot to not work and fuss around some more with the kick up rudders from the plans. I wish I had gone with the rudders grit went for.