Lagoon mast postion

[daletournier]

Im absolutely surrounded by lagoons everyday at the moment. Here in the Seychelles theres alot in charter.

Because i get to look at them everyday ive noticed the new models all have their masts along way back, not prout back but definately futher back than the older lagoons and other brand cats.

Does anyone know the reasoning why lagoon has gone this way? Benefits? Drawbacks?

[alex_sauvage]

Originally Posted by daletournier

Im absolutely surrounded by lagoons everyday at the moment. Here in the Seychelles theres alot in charter.

Because i get to look at them everyday ive noticed the new models all have their masts along way back, not prout back but definately futher back than the older lagoons and other brand cats.

Does anyone know the reasoning why lagoon has gone this way? Benefits? Drawbacks?

Smaller, easy to handle main and bigger fore triangle, so you can have self tacking jib and still generate some power. Code 0 or similar for off wind work. It is a reasonable setup. Drawback would mast in the middle of living space, if it bothers someone

[cyan]

I stepped onto a new Lagoon 42 at a boat show recently, and the sales guy spent a lot of time to convince me that moving the mast aft greatly decreases hobby-horsing. I did not subscribe to his shaky concept of physics, but that doesn't mean it is not actually true.

I do think I like the self-tacking jib.

[Bean Counter]

This is factory rationale
Matrix evolution ! | Lagoon Inside

[daletournier]

Originally Posted by Bean Counter

This is factory rationale
Matrix evolution ! | Lagoon Inside

Makes sense. I like the idea of more foresail options. Im in the process of purchasing a code zero, Id also like a inner foresail with a self tacking jib, I like the idea of options, i believe the big genoa is very limited not allowing you to change gears efficiently.

[arsenelupiga]

Originally Posted by daletournier

Im absolutely surrounded by lagoons everyday at the moment. Here in the Seychelles theres alot in charter.

Because i get to look at them everyday ive noticed the new models all have their masts along way back, not prout back but definately futher back than the older lagoons and other brand cats.

Does anyone know the reasoning why lagoon has gone this way? Benefits? Drawbacks?

gains on reaching / downwind performance and loses some on upwind performance. Easier to get off the hook if caught with too much sail downwind as main is smaller.

Pitching, probably true. However boat has to have more structure to support mast further back hence heavier which may not be bad thing - see hurricane victims. Balsa core under water to increase stiffness.

you gain some, you lose some....

[BigBeakie]

As has been pointed out before, anyone considering an aft mast rig from Lagoon would be well advised to consider very, very carefully they have chosen to support the aft mast compression forces, and the longer term boat longevity implications.

[Emerald Sea]

Originally Posted by BigBeakie

As has been pointed out before, anyone considering an aft mast rig from Lagoon would be well advised to consider very, very carefully they have chosen to support the aft mast compression forces, and the longer term boat longevity implications.

Can you explain in more detail what you mean here? Thanks

[Jim Woodall]

Originally Posted by BigBeakie

As has been pointed out before, anyone considering an aft mast rig from Lagoon would be well advised to consider very, very carefully they have chosen to support the aft mast compression forces, and the longer term boat longevity implications.

I'm also curious about what you are referring to. I looked at an owner's manual for a new Lagoon 42 and at least part of the support system is an additional crossbeam.

[BigBeakie]

I am reluctant to expand on this topic , as last time I did, the Lagoon fan boys seemed to take some exception, however since it is quite an important safety issuet, and since I am genuinely curious about how Lagoon support the aft mast....well, here goes.

Here is a quote from the Lagoon statement ( from the link in an earlier post) about the aft mast position on the newer designs ie. the 52, then the 39, and now the 42.

" This leads to a substantial extra weight which can become negative for the sailing performance. We made this comment to VPLP (our naval architecst) as we wanted to improve performance without neglecting comfort. VPLP has an unequalled offshore racing experience and they came with architectural proposals that you only see in the racing world as the mast aft centered. "

This quote seems to imply that VPLP, with their extensive offshore racing experience ( which is undoubtedly true!), brought advanced racing rig technology to Lagoon in the form of an aft mast configuration. However, the reality is that VPLP actually "borrowed" this idea and execution from a cruising catamaran that was being built in China. They went into a Chinese shipyard where a Freeflow 52 design was being built and, while the designers foreman was away at lunch, proceeded to examine the Freeflow 52 very closely indeed and in particular the aft mast construction. They saw how the mast was supported by a very clever composite engineered structure. They were reportedly very excited and animated about the design features of the Stanton Freeflow 52. Observers joked that it would not be too long before they gave the idea to Lagoon. They were joking at the time, but as it happened, the Lagoon 52 made it's arrival in the months following this visit. Imagine that!

What is a bit baffling is that although they saw how to support the mast in this aft position properly with composite engineered components, the Lagoon aft mast seems to have a cross beam arrangement of some sort. I say of some sort because I have asked Lagoon at several boat shows and I have heard as many different explanations as people I've asked, which to me means they have no idea. However, one Lagoon technical fellow, who sounded like he knew a bit about boat building, reported that it was a steel RSJ encased in fiberglass. Not stainless steel mind you, mild steel. We had a bit of a chuckle about that re 1. an RSJ is very heavy in the profile that would be needed to resist the mast compression forces involved without deflection. These vertical forces are commonly 1.8 to 2 times the mass of the boat. A ridiculous solution for a multihull. Absurd, in fact. Remember what it said in the quote above about wanting to save weight?
And 2. encasing metal in fiberglass is a very, very bad practice. Especially for a structural member, and especially since they use a peroxide catalyst resin which will cause runaway corrosion in mild steel.

If this is true, and it is hard for me to believe that Lagoon would use such shoddy build practices, then there is cause for concern IMHO. If the beam is another material, and I can't think of one that would work re either required stiffness or material degradation, then it would be great to know what it is.

You can go to various websites that calculate beam deflection such as Engineering toolbox for yourself and look up the bending moments for various materials, say stainless steel for example, and use 2 times the dry weight of the Lagoon model as the point loading force. Regardless, you get cyclic load weakening, oxygen induced corrosion or oxygen depleted corrosion (as in stainless), or various other nasty things happening.

It's a helluva stupid way to build a boat, especially when VPLP saw how to do it properly with materials that actually work. To be fair to VPLP (aside from the ethics of them copying the IP of another designer and not attributing credit where credit was due), it is possible that VPLP did tell Lagoon how to do it properly, and Lagoon chose the beam solution as a cheaper/faster option (which it certainly is), and that would NOT surprise me.

So, if anyone actually KNOWS how Lagoon do the beam, and of what material(s), then I, for one, would like to hear about it. I;m not suggesting that bad things will happen within whatever warranty period is applicable, but sometime down the line.....who knows?

[PaulinOz]

Interesting Story BigBeakie. The way you wrote I assumed you actually new what was going on, that was until I got to

Originally Posted by BigBeakie

So, if anyone actually KNOWS how Lagoon do the beam, and of what material(s), then I, for one, would like to hear about it.

Some one who actually knows the facts will hopefully chip in sooner than later and set us all straight on the matter.

What cruising cat did you end purchasing?

Quote from your post back in Jan 2014 Originally Posted by BigBeakie "We are actively searching for a bluewater liveaboard cat to firstly cruise the Oz East coast and GBR for a year and then head into the great unknown of the South Pacific."

[Just Another Sa]

Originally Posted by Bean Counter

This is factory rationale
Matrix evolution ! | Lagoon Inside

Are you sure about that has anything to do with factory?
A lot of unsupported or even false claims, and also in links given as sources like: Les voiles
having a bogus formula for induced drag as an example.
And lagoon inside gave that link to support there reasoning for sloop rig aerodynamics, while that link is only about a cat rig, meaning mainsail only.
Calculating AR for main only in a sloop rig has no aerodynamic merit at all.
Higher angle between mast and forestay means higher mast compression, not less, for a given headstay tension or a given luff sag, because it requires more load from the shrouds to support horizontal loads induced by the forestay, while the difference in tension of leeward and windward shrouds remain the same for a given heelingmoment (same sail area and windspeed & -angle).
Both articles are surprisingly low quality for anything to do with factory and gave the impression they have no idea what they were talking about.
I would sure hope any personnel responsible for the content of that blog have nothing to do with factory.

[BigBeakie]

PaulinOz,

Not sure what you mean about me not knowing whats going on? Can you clarify?

I thought I was clear that I asked several Lagoon reps about the aft mast support construction, without any credible response. I asked because I do not know the answer.

Perhaps someone has better information?


Sent from my iPad using Cruisers Sailing Forum

[Catapault]

Originally Posted by BigBeakie

However, the reality is that VPLP actually "borrowed" this idea and execution from a cruising catamaran that was being built in China. They went into a Chinese shipyard where a Freeflow 52 design was being built and, while the designers foreman was away at lunch, proceeded to examine the Freeflow 52 very closely indeed and in particular the aft mast construction. They saw how the mast was supported by a very clever composite engineered structure. They were reportedly very excited and animated about the design features of the Stanton Freeflow 52. Observers joked that it would not be too long before they gave the idea to Lagoon. They were joking at the time, but as it happened, the Lagoon 52 made it's arrival in the months following this visit. Imagine that!

Thats a pretty serious accusation to one of the worlds leading naval architects and yacht builders.... Hope you have proof. I'd be expecting the defamation lawyers to get their pens out about now...

[PaulinOz]

"Not sure what you mean about me not knowing whats going on? Can you clarify?"

Your words not mine

"if anyone actually KNOWS how Lagoon do the beam, and of what material(s), then I, for one, would like to hear about it"

Your words again from the follow up post that I am trying to answer here

"I asked because I do not know the answer.
Perhaps someone has better information?"

I am referring to the design process and construction technique Lagoon is employing, which is what I thought your post was discussing based on some actual knowledge of the subject.

Instead it appears that you have an opinion on the design process and construction methods used by Lagoon, based on some "here say" from a PRC factory and once again your words "I thought I was clear that I asked several Lagoon reps about the aft mast support construction, without any credible response."

So unless I am totally missing something, I do not understand from what basis of information or knowledge you make the statement"As has been pointed out before, anyone considering an aft mast rig from Lagoon would be well advised to consider very, very carefully "

PS: More importantly, besides all this did you buy a catamaran and get out cruising on the East coast of Oz?