Interesting boats

[socalrider]

Interesting... Leen instead of Neel... I do think they're much more appealing as a trimaran trawler than their sailing vessels - though the latter do not have a good reputation for build quality. Wonder what the efficiency and range is, and how the engine access is in those narrow amas versus a standard catamaran.

What's the advantage of a power tri vs power cat in this configuration anyway? Dinghy storage is a bit more awkward... hmm...

 

[Sababa]

As we all know, beauty is in the eye of the beholder. I think the Leen 50 is beautiful, and the Nordic 42, to me, is beautiful in quite a different way. Where we come from, forward sloping windows (like your beautiful Ahi) are really practical, for reducing the greenhouse effect, let alone for being able to see better at night. The Leen's windows, compared to the cats immediately above your post, are much better in this regard.

I love the Leens in theory, but the IKEA-style interiors are a bigger turn-off for me than the ungainly lines.

 

[OldDan1943]

I love the Leens in theory, but the IKEA-style interiors are a bigger turn-off for me than the ungainly lines.

I agree, it does have too much plastic white but, that can be cured by installing some paneling, perhaps teak (?)

 

[Sababa]

I agree, it does have too much plastic white but, that can be cured by installing some paneling, perhaps teak (?)

I fear the trouble may be more than skin deep. Notice all the sharp corners and lack of handholds. The build quality of the other French boats I’ve seen doesn’t inspire confidence either.

 

[Kit_L]

Re. trimarans:

From "Nick the Naval Architect"

Some that I have seen that I like have one engine only in the centre hull—what I don't like about my cat is how hard servicing things like oil coolers and heat exchangers is. There just isn't any room for those engines in the amas. But the right trimaran, a different story.

 

[Mako]

That was the first oddity that struck me was that it is marketed as a “trawler” for 8 knot cruising, yet it doesn’t rely on just one HD main in the center hull. But they do offer the option of three.

That hull is so low drag that your get-home could easily be just a kite sail, or more realistically, the generator running the hybrid drive.

That config could make it a really unique and practical long range cruiser. Perhaps the builder is open to customization in these regards.

 

[rslifkin]

That was the first oddity that struck me was that it is marketed as a “trawler” for 8 knot cruising, yet it doesn’t rely on just one HD main in the center hull. But they do offer the option of three.

That hull is so low drag that your get-home could easily be just a kite sail, or more realistically, the generator running the hybrid drive.

That config could make it a really unique and practical long range cruiser. Perhaps the builder is open to customization in these regards.

A trimaran strikes me as a great target for a hybrid system. Genset(s) in the main hull, electric drives in the amas. Ideally, you'd have a genset and electric drives, plus a standard mechanically driven main in the center hull. Maybe with a controllable pitch prop so you could use the electric drives for a higher speed sprint without the main becoming underpropped as boat speed increases. Or if you wanted all diesel, 2 small engines in the amas for your normal cruising and a bigger one in the center hull for going faster.



Functionally, that seems like it should be a good setup. You get redundancy, extra speed when you want it, and better maneuvering in close quarters without giving up fuel efficiency when cruising slower.

 

[ABfish]

https://www.denisonyachtsales.com/y...Taka-Yacht-2000-Istanbul/8451363?currency=USD

 

[Hippocampus]

Unfortunately due to construction practices I would not be enthusiastic about any of the French production boats in grp. This is a striking difference from the limited run Al boats like Boreal and Artnautica where I think they’re well made BWB with a long fairly problem free service life.
I posted about LEEN saying “if going that way” not implying that would be my choice. For about the same money you could get a twin engine Artnautica 65 or a 19m Deep Water nicely done up. They would be much higher up on my list.
Thanks for the comments on the NT 42. Still having teething pains from PO lack of use. By the time I sell her she’ll be perfect.

 

[Art]

Re. trimarans:

From "Nick the Naval Architect"

Some that I have seen that I like have one engine only in the centre hull—what I don't like about my cat is how hard servicing things like oil coolers and heat exchangers is. There just isn't any room for those engines in the amas. But the right trimaran, a different story.

Nick is cool - Thanks!

Swath Vessel hull design is my choice!

 

[Art]

Swath - Visual tests

 

[backinblue]

Impressive but ugly!

 

[backinblue]

Thanks for the comments on the NT 42. Still having teething pains from PO lack of use. By the time I sell her she’ll be perfect.

I'm with you Hipp. About to start my 5th season with this boat and still finding and fixing things as well as adding improvements. The next owner will get a better boat than I did.

 

[Hippocampus]

Did one Newport to Bermuda on a wood epoxy cold molded tri optimized for racing. Earlier tha year she had done a single handed trans Atlantic race so had no insecurity about her seakeeping capabilities. Although blistering fast her motion was interesting. Like racing cats she floated on the water not in it. Motion was sudden and short jerking. Unlike cats she did better upwind as regards pointing and had a better motion in quartering seas. Cats in those conditions see the wave first on one hull then the other. Depending upon period of the wave they can give a twisting kind of motion. Instead of being broken up into two it’s broken up into three so less disturbing on a tri. Same with head seas. The tris central hull is usually longer and farther forward. The wave strike is divided into three. On a cat there maybe be no division or the strikes close together.

So definitely like tris. But still have the issue of wide beam and problems docking in a cross wind and well as low payload. So for a small mom and pop boat used the way most of us do there maybe better choices. For cruising sail if if want to see a tri done right in my opinion take a look at Rapido

https://rapidotrimarans.com/

They do do a power day boat. Unfortunately no cruising power.

 

[Art]

Impressive but ugly!

Beauty is in the eye of the beholder... in the case/extent of swath hull design... beauty is in the comfort of the riders aboard during heavy sea conditions!

All in all - I'm still a firm admirer of really good mono hull design boats.

Why you may ask?? Well...

1. I don't spend much time in heavy sea conditions - actually, careful not to!
2. I enjoy the usable wide-beam hull inside room and outside deck space
3. Direct drive engine compartment trany, motor, shaft connections easily accessible
4. Less items to maintain... in general
5. Entire pleasure boating community marina locations are over 100 years designed for mono hull boats... when wet or when dry.

And: Lots of nicely built, well tested, lovingly cared for, relatively inexpensive mono hull pleasure cruisers available!

Would love to take a ride on a swath hull boat in heavy seas... don't care to own one!

 

[Hippocampus]

Tris can have main propulsion in main hull. Unlike some cats accessible from inside rather than a deck hatch. Dive train the same as a mono and same maintenance.

On some tris up to fairly large ones amas are retractable making berthing easier and less expensive as well as land storage.

Tris like cats and LDL monos are much more easily driven. So require less fuel, smaller motors and for the same amount of fuel much greater range.

With board up tris draft less. Power would probably not need a dagger board so a non issue.

Tris don’t need fins, fish or gyros. Less to maintain and decrease speed and increase drag.

Much easier to make a tri unsinkable than a mono.

One could even put solar between the alas and with LiFePO not need a genset.

Still think a 50’ or less CF or Al tri with retractable amas would find a decent level of acceptance in today’s market. Surprised there’s no such offerings in power. . Saw a fair number of power mega yacht tris blasting along in the Caribbean but not a one here in the states
.
Think TT is right. The biggest downside is lower payload and less usable interior space for LOA.

 

[twistedtree]

I’m always taken by how light weight these various two and three hull boats are. How much of the efficiency comes from being light weigh vs the hull shape and construction?

Is a catamaran or trimaran design really just a way to more usable space from a given displacement, as opposed to a fundamentally more efficient design?

Another way to look at it would be to compare same-displacement (weight) boats in mono vs two hull designs. Is one really more efficient than the other, or is there just a difference is usable space?

 

[Mako]

I chatted with a swath designer for a possible build and concluded it was not practical. On a 50ft hull the total payload was 5000 lbs. likely you could design for more but then you would need water ballast tanks. They’re probably great once you hit 100 ft like Silver Cloud.

 

[twistedtree]

I chatted with a swath designer for a possible build and concluded it was not practical. On a 50ft hull the total payload was 5000 lbs. likely you could design for more but then you would need water ballast tanks. They’re probably great once you hit 100 ft like Silver Cloud.

So it sounds like they are tuned to a very specific weight range? I know little to nothing about them, but I guess it makes sense since you need to achieve neutral bouyancy by way of a foil moving through the water. So bouyance is dynamically achieved, rather than passively and statically the good old fashion Archimedes way.

 

[Hippocampus]

TT interesting question. From the little I understand frontal plane, 1/2 angle and wetted surface are the most important parameters. A cat and a tri of equal displacement will have equal wetted surface as how much water you push aside is pretty much determined by how much the boat weighs. However entry and finest are different to work with depending upon two or three hulls. Also you can angle the amas up a bit so one is “flying” or just lightly touching the water decreasing wetted surface c/w a cat. The fastest production cruising sailing boat is a tri (Rapido 60). There are also differences in the ride in a seaway. Some prefer cats and some tris. For me at least when the seas are before the beam I prefer a tri. Still a tri is at a disadvantage for usable space. Other than storage for very light things (usually between the alas) the amas can’t be used for much. Other big difference c/w monos for sail at least is you are nearly always on a beat. These things are so fast the apparent wind moves forward and gets stronger and stronger. Friend I shared a house with while in training now owns a multihull dealership. Before building the outbound he loaded us a tri. Wife hated it. Always in mid to high double digits with the rigging singing loudly. Always needing attention. Not at all restful. Have neve been on a power tri for passage. Can’t speak to their behavior.

 

[twistedtree]

TT interesting question. From the little I understand frontal plane, 1/2 angle and wetted surface are the most important parameters. A cat and a tri of equal displacement will have equal wetted surface as how much water you push aside is pretty much determined by how much the boat weighs. However entry and finest are different to work with depending upon two or three hulls. Also you can angle the amas up a bit so one is “flying” or just lightly touching the water decreasing wetted surface c/w a cat. The fastest production cruising sailing boat is a tri (Rapido 60). There are also differences in the ride in a seaway. Some prefer cats and some tris. For me at least when the seas are before the beam I prefer a tri. Still a tri is at a disadvantage for usable space. Other than storage for very light things (usually between the alas) the amas can’t be used for much. Other big difference c/w monos for sail at least is you are nearly always on a beat. These things are so fast the apparent wind moves forward and gets stronger and stronger. Friend I shared a house with while in training now owns a multihull dealership. Before building the outbound he loaded us a tri. Wife hated it. Always in mid to high double digits with the rigging singing loudly. Always needing attention. Not at all restful. Have neve been on a power tri for passage. Can’t speak to their behavior.

I guess I was really thinking more about a cat compared to a mono hull. Given one of each of equal displacement, how much better does the cat perform? That would distill it down to a comparison of hull form.


Sailors talk about polars, which are the fundamental parameters that impact sailing performance. When comparing a mono to a cat, how much is displacement a polar vs hull shape?


In other areas we debate so many things without understanding what the polars are, and it massively confuses the discussion. Like fuel economy with a big engine vs a small engine. The real polar is boat speed, not engine displacement or rated horsepower. There are other lesser polars, but the primary is boat speed.

 

[Hippocampus]

Cats generally do poorly on a beat c/w monos or even tris. Many production cruising cats have low aspect stubby keels that aren’t retractable. They increase wetted surface but only gain a modest amount of lift. Some cats make use of daggerboards which are much more effective so they point fairly well. However a single hull puts more lateral plane deeper in the water and then gains both lift and more lateral plane from its single keel or dagger board or center board. So its more resistant to sliding sideways. A tri has an advantage over a cat in that it has one daggerboard or centerboard. Tip vortex and turbulence at the keel appendage junction also causes turbulence. So having one instead of two is an advantage for those two reasons.
Other advantage of a mono for cruising is you can put a lead bulb at the end of the keel. Multis get virtually all their righting arm from form stability. Monos don’t. You end up sailing them very differently. Heel is a major clue you need to reef on a mono Not true on a multi. Yes you do heel a bit more when overpowered but somehow you just feel it well before it becomes pronounced. But monos will dump air over their leech when heeled excessively so be de powered. Multis won’t. So the sailplan will see more air because it isn’t heeled over.
None of this has much to do with hull shape and more to do with how they interact with the wind.

 

[Simi 60]

If going that way would think of one of these

https://leen-trimarans.com/

The 50 would be more than sufficient for us.

Which brings this out again

If it was aluminium , so wouldn't draw as much or weigh as much, I reckon I'd be on her.

$1,600,000 difference buys a lot of diesel and maintenance

https://www.boatsonline.com.au/boat...n-custom-22m-g-a-glanville-co-trimaran/287363

 

[Mako]

Simi is that some sorta weird Aussie anchor? I can’t figure it out

 

[Simi 60]

Simi is that some sorta weird Aussie anchor? I can’t figure it out

SUPER Sarca


https://www.anchorright.com.au/products/sarca-anchors/

 

[Peter B]

SUPER Sarca


https://www.anchorright.com.au/products/sarca-anchors/

A Super Sarca which has come up backwards. They do that sometimes. Ask me how I know...

 

[Mako]

So it sounds like they are tuned to a very specific weight range? I know little to nothing about them, but I guess it makes sense since you need to achieve neutral bouyancy by way of a foil moving through the water. So bouyance is dynamically achieved, rather than passively and statically the good old fashion Archimedes way.

TT, perhaps you're thinking of hydrofoils? The SWATHs work differently. All the buoyancy for the vessel is provided by the two submerged pontoons with
reserve buoyancy maintained in the upper hulls. As these are "small waterplane" the pounds/tons per inch of immersion is very small, therefore the amount of payload is also.

From what I've read, perhaps only 20% of the world's fleet of SWATHs are under 100ft. Here, I've grabbed this image off of Google.

 

[Hippocampus]

Although SWATH is a great technology as recreational boaters don’t think it’s applicable to us. Although some of us love blue water and it’s beauty most also enjoy the areas where sea interfaces with land. Draft is therefore a concern. We also deal with chop and waves. Swath has the same issues as any multihull. The deck needs to be higher than at least the chop and short period waves below it. This is easily achievable in large vessels but few us are able to afford vessels over 100’.
Did see an interesting metal mega yacht anchored in Rodney Bay. Wish I took pictures. Basically a hybrid. Fully submerged swath like tubes on either side but the center hull had a deep V form from what you could see above the waterline. Suspect it operated in hull speed ranges. Kind of looked like a tri with the amas nearly fully submerged. Circled it in the dinghy to check it out and was asked to leave.

 

[OldDan1943]

I took a trip on a SWATH dive boat named Nekton
We never had heavy weather but some folks were prone to seasickness.
Was not a problem for anyone that I heard
The problem I could see, if they had to do any major engine work, they would have to cut the pods off
They did serve warm cookies after every dive. SMILE

 

[Mako]

Warm cookies are a well-known characteristic of SWATHs