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Old 26-06-2015, 00:20   #91
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Re: Don't use the Main?

i am more and more in crowd that uses main.

There are twisting forces on mast when using jib or spi or gen only when not going straight downwind that I do not like at all. Very little in a way for mast to rotate when say going max against the wind in jib only.

One needs way to bring mainsail down if caught in too much breeze. Jib or gennaker relatively easy to put away.

So far I know that turning around in 33 kn true with 1 reef and not too large waves is non event.

In theory one should be able to winch down to 3rd reef which i think should be good for turning around in 50kn. That should give one ability to get away in any kind of squall with a bit of patience.
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Old 26-06-2015, 05:19   #92
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Re: Don't use the Main?

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Originally Posted by arsenelupiga View Post
i am more and more in crowd that uses main.

There are twisting forces on mast when using jib or spi or gen only when not going straight downwind that I do not like at all. Very little in a way for mast to rotate when say going max against the wind in jib only.
Actually you make an interesting point about twist imparted to the mast when flying just a 'masthead fore-sail'. And carbon mast are not that crazy about these twisting forces.

You might notice that my aft-mast rig has a masthead backstay that counters this twist at the masthead unlike a conventional catamaran's rig.

Quote:
One needs way to bring mainsail down if caught in too much breeze. Jib or gennaker relatively easy to put away.

So far I know that turning around in 33 kn true with 1 reef and not too large waves is non event.

In theory one should be able to winch down to 3rd reef which i think should be good for turning around in 50kn. That should give one ability to get away in any kind of squall with a bit of patience.
You might have a look at some of the subject threads related to the dismasting and abandonment of the Gunboat catamaran 'Rainmaker' (reefed in sudden wind).
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Old 26-06-2015, 21:39   #93
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Re: Don't use the Main?

Our main sail is always up...a good trimmed main will give lift while motoring head on into any wind. It is stange to me to see any sail boat motoring without there main up. Our topping lift is the same size as our main halyard so if sailing down wind with spinnaker or screacher alone crank down hard on your main sheet eliminates any incorrect mast bend.

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Old 28-06-2015, 10:53   #94
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Re: Don't use the Main?

...another subject thread lamenting some problems with the use of mainsails

Reefing for older people (and boats!)
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Old 28-06-2015, 11:01   #95
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Mainsail Failure results in Aborted Attempt at Solo Sailing Record

So what happens when you have spent a fortune on a vessel to solo sail the world, and a little old mainsail failure (hi-tech sail at that) aborts that attempt,.... OUCH

North 3D Mainsail failure - Boat Design Forums
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Old 28-06-2015, 15:26   #96
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Lagoon appears ready to redefine the mainsail

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Perhaps we need to take another 'tack' at the reasoning here.

The sailboats illustrated here are fractional rigged boats, much like most of our catamarans are rigged,....our headsails are much smaller than the mainsails. So if we reduce the size of the mainsails (by making them roller furling, or eliminating their roach, or eliminating their fat-heads, etc, we are going to significantly cut the boat's performance, because we don't have headsails large enough to make up the difference !! We have potentials to make the rigs more effective by increasing the size of the sails that we can make more effective, but we continue down the path of making the following sail (the mainsail) ever bigger and the headsail ever smaller.

Interesting new twist, Lagoon 52 design moves mast aft to carry larger headsails and smaller mainsail.

Boat Review: Lagoon 52 - Sail Magazine

Although you might not immediately notice the differences between this boat and its predecessors, they are dramatic. For example, moving the mast back to the 43 percent point to get a larger foretriangle required moving the center of buoyancy of the hulls aft as well. That, in turn, meant reshaping the hulls and making the bows sharper, not to mention adjusting the overall center of lateral resistance to keep the boat balanced with the big jib and small mainsail.

Moving the mast aft also required some kind of new support, as the main bulkhead at the forward end of the saloon is no longer usable as a base. That meant creating an entirely new support structure: which Lagoon has done in the form of a big, stiff, reinforced grid concealed within the cabin and hull, and a strong compression post in the middle of the boat

Putting the helm up on a flybridge created yet more structural challenges due to the strains of the running rigging and the weight of people up there. Finally, the short boom (another result of the aft position of the mast) calls for a taller rig to replace the lost sail area.

Amazingly, all of it works on the Lagoon 52: the tall rig is efficient; the mainsail is easy to trim, raise and furl (although the standard electric halyard winch is still essential); the roller-furled headsails behave nicely; and the boat really goes. VPLP Design got it right.


And now the new Lagoon 39 moves its mast aft as well.
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Old 28-06-2015, 20:00   #97
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Re: Don't use the Main?

Beiland,

Interesting reference to the Lagoon 52 with aft mast. It is another article that reads like VPLP have "invented" or "come up with" the aft mast innovation.
This article states "VPLP Design got it right."

This just is not true, and for starters denies Lock Crowther's work on catamaran aft mast many years ago. I spoke personally to Lock about his ideas on this, but at the time the support for the mast bothered him.

One thing I detest is IP theft. I have been on the receiving end of it in the past, and aside from the questionable ethics of taking other peoples work and pretending it is your own without giving credit to the innovator, it shows that the poacher is somewhat bereft of ideas.

Since this is not the only article which portrays that the aft mast solution is a VPLP/Lagoon innovation, I have to assume that these marine journalists are being misled by Lagoon and/or VPLP as to their actual role in making this aft mast work in cats, because it seems VPLP did not come up with the solution, it seems they directly poached it from a Kiwi-Australian designer, Nathan Stanton, when they saw & closely examined his composite engineered solution to the aft mast load issue on his 52 foot cat being built in China by a Chinese builder, who let VPLP examine the boat at length and in detail when the designer was not present, and without his permission. The Lagoon 52 & 39 came out afterwards.

There is photographic evidence of this aplenty, including on the Chinese builders website, as well as eyewitness accounts.

The article states "That meant creating an entirely new support structure: which Lagoon has done in the form of a big, stiff, reinforced grid concealed within the cabin and hull"

Another CF poster has referenced a French article that says VPLP used an
RSJ (steel I-beam) in the Lagoon 39 to provide a load path for the mast compression forces. That is such an inelegant solution for a sailing boat, let alone a cat, that it is hard to believe VPLP/Lagoon would stoop to that level, so maybe that marine journalist misunderstood something. Then again, maybe not...

Anyway, I just thought I'd point this out, AGAIN. The marine industry is awash with people "borrowing" good ideas, but that doesn't mean you shouldn't give credit where credit is due.

"Imitation is the sincerest form of flattery!", and all that, but a design firm of VPLP's reputation and stature in the industry claiming credit for this in public is pretty disappointing.

I'd be delighted to be wrong on this. If VPLP or Lagoon have acknowledged the prior art of Nathan Stanton wrt aft mast support, then I have missed it, which is entirely possible. And if so I would happily plead mea culpa. But from these articles being written, it seems not.
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Old 28-06-2015, 20:53   #98
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Re: Don't use the Main?

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Originally Posted by Sailingcouple13 View Post
Our main sail is always up...a good trimmed main will give lift while motoring head on into any wind. It is stange to me to see any sail boat motoring without there main up. Our topping lift is the same size as our main halyard so if sailing down wind with spinnaker or screacher alone crank down hard on your main sheet eliminates any incorrect mast bend.

Sent from my SM-G900P using Cruisers Sailing Forum mobile app

I'm sorry but physics doesn't support this view. To move a boat you need energy, provided by the wind or engine or both. Acting against forward motion is drag, from the hull and sails.

Motoring directly into the wind the sail will add drag, but not thrust assisting forward motion. You may be able to trim the sail but the thrust line will be offset and not add to the net forward thrust.

Off the wind at some critical angle any actual (true) wind will start to provide assistance once the sail drag is overcome. The sail up in nil wind, with only the apparent wind due to forward motion of the boat under motor, does not add energy.

In other words you can't pull yourself up by your bootstraps.


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Old 28-06-2015, 21:18   #99
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Re: Don't use the Main?

Huh? (Yes, not directly into the wind.)


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Old 29-06-2015, 16:09   #100
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Original of Mastaft Rig

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Originally Posted by BigBeakie View Post
Beiland,

Interesting reference to the Lagoon 52 with aft mast. It is another article that reads like VPLP have "invented" or "come up with" the aft mast innovation.
This article states "VPLP Design got it right."

This just is not true, and for starters denies Lock Crowther's work on catamaran aft mast many years ago. I spoke personally to Lock about his ideas on this, but at the time the support for the mast bothered him.

One thing I detest is IP theft. I have been on the receiving end of it in the past, and aside from the questionable ethics of taking other peoples work and pretending it is your own without giving credit to the innovator, it shows that the poacher is somewhat bereft of ideas.

Since this is not the only article which portrays that the aft mast solution is a VPLP/Lagoon innovation, I have to assume that these marine journalists are being misled by Lagoon and/or VPLP as to their actual role in making this aft mast work in cats, because it seems VPLP did not come up with the solution, it seems they directly poached it from a Kiwi-Australian designer, Nathan Stanton, when they saw & closely examined his composite engineered solution to the aft mast load issue on his 52 foot cat being built in China by a Chinese builder, who let VPLP examine the boat at length and in detail when the designer was not present, and without his permission. The Lagoon 52 & 39 came out afterwards.

There is photographic evidence of this aplenty, including on the Chinese builders website, as well as eyewitness accounts.

The article states "That meant creating an entirely new support structure: which Lagoon has done in the form of a big, stiff, reinforced grid concealed within the cabin and hull"

Another CF poster has referenced a French article that says VPLP used an
RSJ (steel I-beam) in the Lagoon 39 to provide a load path for the mast compression forces. That is such an inelegant solution for a sailing boat, let alone a cat, that it is hard to believe VPLP/Lagoon would stoop to that level, so maybe that marine journalist misunderstood something. Then again, maybe not...

Anyway, I just thought I'd point this out, AGAIN. The marine industry is awash with people "borrowing" good ideas, but that doesn't mean you shouldn't give credit where credit is due.

"Imitation is the sincerest form of flattery!", and all that, but a design firm of VPLP's reputation and stature in the industry claiming credit for this in public is pretty disappointing.

I'd be delighted to be wrong on this. If VPLP or Lagoon have acknowledged the prior art of Nathan Stanton wrt aft mast support, then I have missed it, which is entirely possible. And if so I would happily plead mea culpa. But from these articles being written, it seems not.
Hi BigBeakie,
I wouldn't be so hard on criticizing VPLP, nor Lagoon on this matter. There are many things in the boating design world that are 'evolutionary' in their being. Even my aft mast design is a product of previous work as explained on my website.

Sail Propulsion - Revisiting a Mast-Aft Sailing Rig

Quote:
Originally Posted by excerpt
With Marchaj's book as my technical guide, I began a search for alternatives to the traditional Bermuda rig. Fore to aft sails must be retained for their windward ability, and the single-masted rig would be preferred for its simplicity. There are three basic positions for a single-masted sailboat: in the bow ~~ which is a cat boat, in the middle ~~ which is the bermudian sloop or cutter, or in the stern ~~ which is a ....? As Garry Hoyt noted, "the fact that this stern-placed rig has no official name attests to its almost complete lack of popularity". But maybe placing this aerodynamic hindrance at the rear of the sailplan makes sense? Years ago Victor Tchetchet experimented with it calling it the "mastaft" rig. Garry Hoyt, world renown for his cat rigged Freedom boats, built a rear masted prototype he called the "Delta 26". In 1964, a McCurdy & Rhodes 46' "staysail ketch" stepped the mast aft to eliminate headsail overlap and permit the genoa to be self-tending. Prout catamarans have made use of mast aft rigs (albeit very conservative, small sail-area rigs) for years. And finally a "staysail cutter" rig proposed by a maritime artist and historian, Melbourne Smith had a significant impact on my thought processes.


I can't find either of the 'illustrations' of either Tchetchet's mastaft catamaran experiement, nor Smith's cutter. I guess I have lost them over the years of moving around the world, as they were non-digital formats (just printed matter) when I began working on the aftmast idea in 1972,...wow...43 years ago.

You will find some copies of my first published work in the archives of my website:

1974
RunningTideYachts, Ltd. - Archives
1974 RunningTideYachts, Ltd. - Archives

I never became computer literate until 2000, so I was never in a digital format till then. If I remember properly there were a number of occasions that I presented these mast-aft ideas to the production catamaran builders in the mid 1980's and the 1990's down at the Annapolis boat shows. I also presented then to Fountain/Pajot when I was their importer. After I first published my website in 2000, I put more emphasis on trying to find a production builder that might consider experimenting with the idea.

I just remembered another considerable influence on me. During the early years of the Annapolis Boat Show I had a display of beach cats right down at the head of the show, and right next to me was Bill Symons with the Prout catamarans.

I also remember talking with Lock Crowther about this idea way back in a year that he visited the Annapolis Boat Show.

I will say that no one before me, that I can think of, ever presented the idea of a 'ketch-rigged version'
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Old 29-06-2015, 16:23   #101
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Re: Don't use the Main?

BTW, here is an index page (1955-1996) from the Amateur Yacht Research Society listing those possible illustrations by Tchetchet and myself.


Sails and rigs - sail plans, masts and spars, design criteria, handling
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Old 29-06-2015, 17:00   #102
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Re: Don't use the Main?

" Hi BigBeakie,
I wouldn't be so hard on criticizing VPLP, nor Lagoon on this matter. There are many things in the boating design world that are 'evolutionary' in their being.
"

Hi Brian,

Yeah, sure, I acknowledge that good ideas will get spread due to their merit as others "borrow" the idea over time. I don't have a problem with that, unless the idea is under patent protection.

But a designer climbing all over another designers new design-new boat, without permission, with tape measures and camera....just sucks. I'm surprised you would condone it, being a designer yourself.

I maintain it is highly unethical. This was not just an employee of VPLP, this was principle designer. I had previously considered VPLP a class act, but actions speak louder than words.
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Old 29-06-2015, 18:04   #103
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Re: Don't use the Main?

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Originally Posted by BigBeakie View Post
" Hi BigBeakie,

I wouldn't be so hard on criticizing VPLP, nor Lagoon on this matter. There are many things in the boating design world that are 'evolutionary' in their being.
"



Hi Brian,



Yeah, sure, I acknowledge that good ideas will get spread due to their merit as others "borrow" the idea over time. I don't have a problem with that, unless the idea is under patent protection.



But a designer climbing all over another designers new design-new boat, without permission, with tape measures and camera....just sucks. I'm surprised you would condone it, being a designer yourself.



I maintain it is highly unethical. This was not just an employee of VPLP, this was principle designer. I had previously considered VPLP a class act, but actions speak louder than words.

This seems like a bit of petty backbiting. Why would VPLP or Lagoon bother measuring another design to copy when they have the ways and means of coming up with there own designs, let alone a design that hasn't even been launched and tested. Measuring would give them no useful information in regard to engineering the design or the performance and they have been building and designing big cats for long enough to figure it out for themselves.
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Old 29-06-2015, 18:30   #104
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Re: Don't use the Main?

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This seems like a bit of petty backbiting. Why would VPLP or Lagoon bother measuring another design to copy when they have the ways and means of coming up with there own designs, let alone a design that hasn't even been launched and tested. Measuring would give them no useful information in regard to engineering the design or the performance and they have been building and designing big cats for long enough to figure it out for themselves.
Monte,

Believe me, I understand your questioning this. I was incredulous myself when I heard about it. But nevertheless, it happened. If this actually occurred, would you still consider that "petty backbiting?"

And you are misunderstanding what took place. You do not know what was being measured, and why, or why the innovation was of interest to them.

And most definitely their actions clearly indicate they did not know how to figure it out for themselves, or the incident would never have occurred in the first place.

You are giving VPLP way more credit than they deserve.

Since you are one of their customers, why don't you find out exactly how the mast compression load path is handled in the L39 aft mast? Is it as that French article states, that it is a steel beam under the saloon floor?
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Old 29-06-2015, 19:11   #105
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Re: Don't use the Main?

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Monte,



Believe me, I understand your questioning this. I was incredulous myself when I heard about it. But nevertheless, it happened. If this actually occurred, would you still consider that "petty backbiting?"



And you are misunderstanding what took place. You do not know what was being measured, and why, or why the innovation was of interest to them.



And most definitely their actions clearly indicate they did not know how to figure it out for themselves, or the incident would never have occurred in the first place.



You are giving VPLP way more credit than they deserve.



Since you are one of their customers, why don't you find out exactly how the mast compression load path is handled in the L39 aft mast? Is it as that French article states, that it is a steel beam under the saloon floor?

Your right BB, I don't know exactly what took place. Would you mind referencing some facts and I'll take a look?
I'm not sure about the innovation you're referring to but if it's a mast stepped further aft it's hardly innovation. Prouts have had a similar sailplane for 40 years and it's likely masts have been placed in every conceivable position, for/aft/off centre in that time as well. Engineering the support for the mast is pretty basic stuff.
As far as the L39, I don't know how they handled the compression from the mast, but being nautical engineers I expect they have enough nouse to figure that out as well without me questioning their methods. If they decided a steel beam is the best method I wouldn't presume to know better myself. As customers we buy a product fit for the purpose we require. If our requirement is maximum performance, minimum weight, high tech construction materials with an unlimited budget, our choice of boats is likely to be very different from cruising performance, industry standard materials on a limited budget.
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