Why so many Lagoons on the market?

[smj]

It turns me of enough going to a boat show and walking through a new cat that has floorboards that creak, cabinets that squeak against the fiberglass while sailing? No no
No.

[Barra]

Ok I'll be more clear for you.

Lagoons I've been in heavy seaways flex significantly more than other cats I've been on in similar conditions. Some boats like catana hardly flex at all. Older fps are pretty bad too. But none are worse than lagoon in my experience. The bigger ones are the worst. You don't just hear it you see it.

Therefore to say a lagoon is a rigid built cat lacks comparisons.

Obviously it's better if a cat doesn't overly flex they arent airplane wings but it's a cost compromise and catana for example cost way more than lagoons for a reason.

Flex equals fatigue failure. But not within 5 to 7 years typically which is why it's a compromise the charter fleet buyers are prepared to make. My original point.

Flex also gives loose suboptimal rigging. The rigger is obviously all over the flex in hulls because it affects the rigging and vice versa. He works on different cats every day looking at exactly this so I'll defer to that experience.

Originally Posted by redneckrob

The wings on a 787 routinely flex through a 20+ foot range during flight. Is that per se bad? You can't make a multi-ton ship 50'+ long and 30'+ wide with two hulls that doesn't flex, from a mechanical engineering perspective it's not only a fools errand to try but to do so would actually compromise the structural integrity of the boat. So saying a catamaran flexes in a seaway as if that is unambiguously and universally bad is pretty meaningless. Issues caused by the flexing on Lagoons that aren't caused by flexing on similar sized makes would be far more useful. My FP certainly flexes, and the worst impact of that is that if you have part of the carpentry that rubs against fiberglass the noise is annoying, but that's easily rectified and certainly not something that concerns me.

BTW, the forestay is connected to a solid forward crossbeam on every Lagoon (actually every cat) I've seen. Given the geometry of the remaining mast stays, it doesn't make much sense how tightening the forestay would bring the hulls together or why one would have loose forestay issues with a catamaran to start with? Is that something you've personally experienced, not being able to tighten a catamaran forestay sufficiently? Because it's not something I've ever experienced or even heard of as an issue? Perhaps this mythical rigger isn't the best guy to have working on any cat, Lagoon or not?

[redneckrob]

Originally Posted by Barra

Ok I'll be more clear for you.

Lagoons I've been in heavy seaways flex significantly more than other cats I've been on in similar conditions. Some boats like catana hardly flex at all. Older fps are pretty bad too. But none are worse than lagoon in my experience. The bigger ones are the worst. You don't just hear it you see it.

Therefore to say a lagoon is a rigid built cat lacks comparisons.

Obviously it's better if a cat doesn't overly flex they arent airplane wings but it's a cost compromise and catana for example cost way more than lagoons for a reason.

Flex equals fatigue failure. But not within 5 to 7 years typically which is why it's a compromise the charter fleet buyers are prepared to make. My original point.

Flex also gives loose suboptimal rigging. The rigger is obviously all over the flex in hulls because it affects the rigging and vice versa. He works on different cats every day looking at exactly this so I'll defer to that experience.

You maintain that "Obviously it's better if a cat doesn't overly flex" but that is neither obvious nor is it clear what constitutes "overly". That's why I very specifically asked what the detrimental impacts of this flexing were. An assertion that it causes "fatigue" is also rather vague and meaningless. There are more Lagoons out there than any other cat, they've sails hundreds of thousands of miles over decades. None have been lost to "fatigue" of any kind that I'm aware of let alone fatigue caused by flexing. I'm not aware of any specific pattern of damage caused by fatigue that's endemic on larger Lagoons? Nor is there any indication that this flexing causes issues with forestay tension or loose or suboptimal rigging issues, again there are a couple thousand of these boats out there and if it was a manufacturer-wide problem we'd see lots of reports right here on CF. Just look at some of the much more minor single model issues like the Lagoon 400 nacelle drainage issue that got tons of coverage here. While you may be able to dig up one or two examples, that would represent .1% or less of the Lagoon fleet.

I spent a career as a pilot running aircraft maintenance programs, flying the H-65 which is largely composite. We went to great lengths to measure fatigue and the impacts of fatigue on a fleet of over 100 airframes that all had over 10,000 hours of tough flying on them by the time I retired. It is most certainly not "obvious" to even an engineer what constitutes excessive flexing and when it will cause problems. It's highly dependent on a whole litany of factors like the types of stress on each section of the structure, the material used, the number of stresses it's subjected to, the magnitude of those stresses and the distribution curve of those magnitudes, the maximum stresses....I could go on and on. Our main rotor blades were a composite that flexed up to 10 degrees at the root 360 times a minute and they were good for thousands of hours of flight time which equals millions of flexes, so no, "flex doesn't equal fatigue failure", flex outside of design parameters is what causes fatigue failure. I wasn't the engineer who designed the aircraft and although I cared a lot about fatigue (as I also spent several thousand hours flying the aircraft) and knew a good deal about it specific to our specific model, I didn't have the hubris to try to tell the aeronautical engineers that there was "obvious over flexing" based on nothing more than my opinion that all flexing was per se bad and a few hours observing said flexing with no observed ill effects. If you or your rigger actually studied all those specific fatigue factors for a specific model of catamaran I'd be excited to hear your thoughts on how you came to the conclusions you did. If not, then all we can do is revert to the fact that there aren't any obvious significant negative impacts over a statistically meaningful fleet and assume that the mechanical engineers and naval architects who actually did do all that analysis on these boats are perhaps the folks we should be listening to on these matters?

I'm an FP guy myself and am not a Lagoon fan purely for personal aesthetic reasons. But there's no indication they have fatigue issues or rig tensioning issues and it's not helpful to new folks trying to learn about their options to malign an entire fleet of boats for issues they don't actually have based on unsupported inexpert opinions. If you don't like Lagoons and can afford a Catana, buy yourself a Catana and spend your time enjoying it. Life's too short to do anything else.

[Barra]

^^^

Well I can see how you are able to rub people the wrong way.

Never said half the straw man arguments you are trying to put in my mouth.
I have simply pointed out a few facts. Primarily that lagoons are not rigid boats. You can choose to believe that isn't an issue but you can't deny it's a fact.

I guess you are just an argumentative sod and life is too short for that so I will leave you to argue with someone else.

[Yihang]

Composite Wings like on the 787 flex fairly evenly over it's length. It's also designed to flex to generate extra lift and buffer turbulance.

Catamarans are not engineered to such degrees. Flex is most likely tolerated rather than designed. There are no plywood furniture in the wings of a 787 to squeak.

Although whatever flex is in a lagoon is most likely not going to render it unseaworthy. But there are more rigid designs out there. Like the seawinds.

[CatNewBee]

Probably lost in translation.... So sorry for that. With rigid I don't meant, they do not flex. 3 years ago I saw one 420 run by an inexperienced and overmotivated charter crew on engines and autopilot during the night on the rocks of the wave breakers in the anse in Toulon.

Severe damages on the hulls, scratches, some water ingress, but the bilge pumps could manage it, they limped to the port and were hauled out the next day. I had a look at the damages and the various layers of fiberglas under the waterline, rigid, solid quite thick fiberglas, no core material.

There was also an older Nautitech, that was burned down by a fire at anchor, the hull was not even half that thick.

[arsenelupiga]

Originally Posted by Yihang

Composite Wings like on the 787 flex fairly evenly over it's length. It's also designed to flex to generate extra lift and buffer turbulance.

Catamarans are not engineered to such degrees. Flex is most likely tolerated rather than designed. There are no plywood furniture in the wings of a 787 to squeak.

Although whatever flex is in a lagoon is most likely not going to render it unseaworthy. But there are more rigid designs out there. Like the seawinds.

Sure about that ? did you sail seawind and Lagoon? Our seawind 1000 shroud was loose in 15 kn beam reach. Never seen loose shroud on our Lagoon 400 yet. And we do 10 kn boat speed.

[Yihang]

Originally Posted by arsenelupiga

Sure about that ? did you sail seawind and Lagoon? Our seawind 1000 shroud was loose in 15 kn beam reach. Never seen loose shroud on our Lagoon 400 yet. And we do 10 kn boat speed.

The newer seawinds with the composite interior modules/bulkheads are design to stiffen the boat, have you sailed those and seen shrouds loosen? Not sure about the 1000s. Maybe they were built using traditional plywood bulkheads.

No, I havent sailed seawinds, the club I used to sail had a lagoon 400 when I was there and just got a 1160 after I left. The 400 was fine, didn't notice anything on the day sails I was on.

[arsenelupiga]

Originally Posted by Yihang

The newer seawinds with the composite interior modules/bulkheads are design to stiffen the boat, have you sailed those and seen shrouds loosen? Not sure about the 1000s. Maybe they were built using traditional plywood bulkheads.

No, I havent sailed seawinds, the club I used to sail had a lagoon 400 when I was there and just got a 1160 after I left. The 400 was fine, didn't notice anything on the day sails I was on.

well you need to sail in strong stuff else all looks pretty. We managed to sail in 50 to 60 kn so far max open sea up to 10 m freak vawes and stiffness is sure not an issue with lagoon 400. They are heavy, thick everything, and that is good for stiffness. New seawinds, not sailed in decent blow. But there were some issues i heard.

[smj]

Originally Posted by arsenelupiga

Sure about that ? did you sail seawind and Lagoon? Our seawind 1000 shroud was loose in 15 kn beam reach. Never seen loose shroud on our Lagoon 400 yet. And we do 10 kn boat speed.

In 15 kts of wind on our Seawind 1000 we never saw a loose shroud, maybe your rig was under tensioned?
Having owned both a Lagoon and a Seawind 1000, surely you know the difference in construction and design?
I will say it again, nothing good about an overbuilt heavy catamaran.

[arsenelupiga]

Originally Posted by smj

In 15 kts of wind on our Seawind 1000 we never saw a loose shroud, maybe your rig was under tensioned?
Having owned both a Lagoon and a Seawind 1000, surely you know the difference in construction and design?
I will say it again, nothing good about an overbuilt heavy catamaran.

yup in 15 kn beam reach full sails. This was considered normal by factory as I questioned this as well. The other guy with Seawind I spoke to had to have heroic climb up the mast while sailing to save mast as he was seeing shroud just about to separate from mast - reason was loose shroud eventually managed to undo connection.

Regarding build quality, people have different priorities and planned uses. So pointless discussing this from point of view of coastal sailor vs one that plans long ocean passages.

[JamesPNW]

My Cat is in Valencia, Spain. Got stuck there with Covid-19.

[Uncle Bob]

Why so many Lagoons on the market?
Why indeed, probably because they are such an attractive, sporty performance vessel.

[redneckrob]

Originally Posted by Barra

^^^

Well I can see how you are able to rub people the wrong way.

Never said half the straw man arguments you are trying to put in my mouth.
I have simply pointed out a few facts. Primarily that lagoons are not rigid boats. You can choose to believe that isn't an issue but you can't deny it's a fact.

I guess you are just an argumentative sod and life is too short for that so I will leave you to argue with someone else.

Actually now that you agree that a lack of rigidity (in boats at least) isn't an issue in and of itself, I agree with you. And as you may have noticed, I not only never asserted that Lagoons are rigid boats, my entire point was that the flexibility they have isn't necessarily a bad thing. So again, I agree with you and always have; they're flexible boats! I'm sorry if you find it argumentative when someone points out that an alleged flaw on an entire manufacturer's 2000+ boat fleet doesn't actually have any negative consequences and therefore probably shouldn't be considered a flaw. And as I offered several times, I'd be very open to learning about any specific negative consequences you've personally experienced or can provide links to, as that would be useful knowledge to all of us.

My goal in this conversation was to make sure someone who is coming to this forum new to the community looking for information isn't led astray and ends up avoiding the largest cat manufacturer because of alleged issues they read about here that aren't, in fact, issues. The real question, if you're calling that argumentative (and feel compelled to launch personal attacks and name calling in an engineering discussion of all places!), is what your goal in the conversation is?

[Lance]

Originally Posted by 75Driver

Thanks for the feedback. Charters and big production numbers makes sense. I like the boats and when this COVId mess finally settles we’re heading to Florida for some deck time on several of the major players. We might get a trawler or something similar as wifey is more interested in starting out with the loop. She’s less enthused about ocean cruising although I prefer it.

Thanks again for the insight.

You must remember these boats are predominantly designed as luxury living accommodation vessels essentially limited to life in the LAGOON .
They are just motor sailors and if considering ocean cruising your actual sailing ability will be hampered and uncomfortable because of low bridge deck clearance , huge weight , and low aspect fat hulls with slow SOG.
Your wife would not be the first lady to demand to go home after ocean passage one .
There are many capable alternatives out there and if you choose wisely you could find a Cat that has the bonus of positive bouyancy .