New Boat, Swedish Delta "Yacht" - anyone got any info? Jack?

[MapisM]

Catamaran?

Naah, cats do have their pros, but surely not some others which are typical of monohulls.
They can't be stabilised, to start with - which is more than enough to rule them out for anyone who rates comfort as crucial for a pleasure boat.

 

[MapisM]

There is some evidence in U.S. that vessels with IPS have lower residuals due to ongoing drive costs.

I'm not sure it's just an economic matter, LS.
None of the US boaters I've had the occasion to talk with would even consider anything but shafts, for a long range cruiser.
Most of them would be happy with just one, along the lines of the "two engines, two problems" philosophy, which is the opposite of the EU approach.
But IPS on a vessel aimed at serious cruising? And maybe 3 or 4 of them?
They'd just laugh at the idea, regardless of the maintenance required.

 

[petem]

I guess that for a shipyard like Delta IPS drives would be the obvious choice as they are newer tech than shafts etc. How easy would it be for them to offer an alternative, would it require a complete reconfig of the lower deck?

 

[rustybarge]

Naah, cats do have their pros, but surely not some others which are typical of monohulls.
They can't be stabilised, to start with - which is more than enough to rule them out for anyone who rates comfort as crucial for a pleasure boat.

Just a guess: 57' by 26' Cat like the Pagot-fountain has nearly the same size accommodation as a 78' monohull.

 

[MapisM]

I guess that for a shipyard like Delta IPS drives would be the obvious choice as they are newer tech than shafts etc. How easy would it be for them to offer an alternative, would it require a complete reconfig of the lower deck?

Difficult to tell, but if they designed the hull, the e/r and the weight distribution with IPS in mind, then yes, the adaptations required might well be significant.
Maybe a bit less so if they'd go for V-drives, but then again, I'd rather not have them in a LRC.

 

[MapisM]

Just a guess: 57' by 26' Cat like the Pagot-fountain has nearly the same size accommodation as a 78' monohull.

Yep, probably, but so what?
My previous point still stands, you can't stabilise that vessel.
I know, you might argue that you don't need to, but that's only true up to a point.
With waves large enough to make a cat roll (and it doesn't take a perfect storm), the roll becomes real BAD.
Not so with a stabilised mono.

 

[rustybarge]

Yep, probably, but so what?
My previous point still stands, you can't stabilise that vessel.
I know, you might argue that you don't need to, but that's only true up to a point.
With waves large enough to make a cat roll (and it doesn't take a perfect storm), the roll becomes real BAD.
Not so with a stabilised mono.

Nearly all offshore wind farm vessels are Cats, never heard of a stabilised monohull being used.........so they have a very good rough weather pedigree in the larger sizes over 18mtrs.

the proof of the pudding.......

 

[MapisM]

I know nothing of wind farm vessels, but I suppose comfort is not their top priority.
Sea keeping and efficiency also at high speed probably is, and cats are good in this respect.
I didn't say that cats aren't good for passage making, just that they aren't as comfortable as monos.
Horses for courses.

 

[rafiki_]

I guess that for a shipyard like Delta IPS drives would be the obvious choice as they are newer tech than shafts etc. How easy would it be for them to offer an alternative, would it require a complete reconfig of the lower deck?

IMHO, most of the selling point with IPS to a boat builder is the space they free up for accommodation.

 

[Jack Haines]

Yep, we spent two days on board the boat in Stockholm two weeks ago. We will be running a full test very soon, an exact issue is yet to be decided.

As usual, the forum finger is firmly on the pulse and most of the info about the company you need to know has already been mentioned.

Obviously I don't want to give away too much before the tests hits the shelves but some initial insights would be:

- Without having crunched the numbers and compared to others I would say fuel efficiency looks extremely impressive; she is also very fast.
- The yard recommends 3xIPS1200 but will fit twins if preferred. Designer Lars Modin is a huge fan of IPS and feels pods is the only way to get the sort of performance, handling and efficiency that he wants from the boat.
- She is all carbon fibre, not just the hull but the superstructure too.
- They are open to customisation - talking to the owner of #1 it is a very close relationship between buyer and builder.
- The interior is typically Scandinavian and not as glossy as a Princess, Fairline or Azimut for example. It's simple, modern and angular but finished to a good standard.

I imagine the test will go into the March issue, out in the first week of Feb, but I'm more than happy to meet you at LIBS, John, and tell you more about what I found.

Cheers,

Jack

 

[sarabande]

can a raggie ask a question about stabs in short rough seas pls ? It arises from comments up the thread about the perceived (and accepted) need to keep the boat 'flat' when under way.

I don't know how quickly stabs can react to moderate the roll of a boat, but is there any possibility of - say, in a sea where wavelength and height are abnormal and disproportionate - the stabilisers getting out of synchronisation with the natural roll period of the vessel, and exacerbating the roll ? Hard to imagine exactly when/where that might happen, but in a very disturbed area such as off Portland Bill, or with a superimposed wave pattern well offshore, the stabs might be trying to correct a roll and are at maximum deflection when along comes another wave and catches the stabs out ?

The bigger the boat the more roll inertia there is that needs to be corrected, and high speed might make that situation worse.

 

[Pinnacle]

The bigger the boat the more roll inertia there is that needs to be corrected, and high speed might make that situation worse.

As one raggie to another......

But I guess the faster you are going the greater the effect the stabs will have for a given angle of attack?

 

[MapisM]

You're actually mixing a few different issues with your question.
I'll try to go through them, assuming that we're talking of fins stabs, which are the most common.

It arises from comments up the thread about the perceived (and accepted) need to keep the boat 'flat' when under way.

Actually, the rolling-induced seasickness is something different from the constantly listing (or not) cruising attitude of a boat.
I mean, it's obvious that it's preferable to move around in an horizontally flat boat, compared to a listing monohull sailboat.
But as long as the listing angle is reasonably stable - as is normally the case due to the stabilizing effect of sails - there's no "need" to keep the boat flat from a seasickness viewpoint. It's just annoying when moving around, or if you want to have a shower or sleep under way, but that's a different matter.

I don't know how quickly stabs can react to moderate the roll of a boat

Istantaneously. It's almost unbelievable how quickly they can sense the rolling motion and react to it, even in rather old equipments like the one in my boat (1995 vintage), which are only driven by a gyroscope. More modern stuff typically have multiple inputs, to fine tune the movements and react even faster. But if I should rate the effectiveness in a 0-100 scale, 0 being a non-stabilized vessel and 100 a total absence of rolling motion, I'd give to my oldish stabs a sound 95, with the newer models possibly achieving 97 or 98 - i.e., no real difference, for all intents and purposes.
Mind, I'm only talking of stabilization under way, which as I understand is what you are interested in.
Zero speed is almost another book, rather than just another chapter.

is there any possibility of ... the stabilisers getting out of synchronisation with the natural roll period of the vessel, and exacerbating the roll ?

Nope, that simply can't happen, because of the physics fins stabs are based on.
If an external force tries to make the hull list (say) to port, both fins instantly rotate (the port fin outward, and the stbd fin inward, but that's a detail), exploiting the water flow to create a contrasting force to make the hull listing to stbd, strong just enough to neutralize the external one.
The higher the external force, the higher the fins rotation, for any given speed.
As soon as the external force is not there anymore (or, as it normally happens, tries to make the hull list in the opposite direction), the fins return centered (or, as required, they rotate the other side).
Now, what if the external force is strong (and longlasting) enough that even at their max angle the fins can't create a force capable of neutralizing it?
Quite simply, the fins would stay at their max angle, till the boat will return "flat". In other words, they would continue to contrast the roll as much as they can, and for as long as necessary.
The boat might well be listing, if the external force (wave) is stronger than the stabs righting force, but surely such listing would still be much be less than with no stabs. There's no such thing as any sort of "synchronisation" the stabs can get out of, and no chance that they can exacerbate the roll (malfunctioning aside, of course).
As an aside, this is one of the major difference between fins and gyro stabs.
When cruising in beam seas with long swells, the latter can only generate the contrasting force for a limited amount of time, therefore they can run out of stabilizing effect after a while. Anyway, I can't think of a situation where gyro could "exacerbate" the roll. They can be not as good as fins in those conditions, but that's it - though I'm far from being a gyro expert, so I'm happy to stand corrected if I'm missing something.

The bigger the boat the more roll inertia there is that needs to be corrected

True, but it's just a matter of sizing properly the stabs, as with any other boat equipment - props, rudder, thrusters... you name it.
Besides, there's another side of the medal: higher inertia also means more time before the roll actually begins, hence more time for the stabs to work their magic, and avoid the roll altogether.

high speed might make that situation worse.

Nope, not at all. Aside from the fact that as Pinnacle already mentioned, the contrasting force generated by the fins increases with the speed (for any given rotation angle), actually when speed increases there is less, not more need for rolling stabilization.

 

[sarabande]

ah, thanks, MapisM, for the detailed reply. It explains a lot. I can now rush out a get one like jfm's ( )

 

[MapisM]

My pleasure.
Re. rushing out and get one like jfm's, LOL, don't forget that on top of the 70k quids or whatever for the stabs, you also need a boat big enough to stick them to her hull...

 

[jfm]

Yep, we spent two days on board the boat in Stockholm two weeks ago. We will be running a full test very soon, an exact issue is yet to be decided.

As usual, the forum finger is firmly on the pulse and most of the info about the company you need to know has already been mentioned.

Obviously I don't want to give away too much before the tests hits the shelves but some initial insights would be:

- Without having crunched the numbers and compared to others I would say fuel efficiency looks extremely impressive; she is also very fast.
- The yard recommends 3xIPS1200 but will fit twins if preferred. Designer Lars Modin is a huge fan of IPS and feels pods is the only way to get the sort of performance, handling and efficiency that he wants from the boat.
- She is all carbon fibre, not just the hull but the superstructure too.
- They are open to customisation - talking to the owner of #1 it is a very close relationship between buyer and builder.
- The interior is typically Scandinavian and not as glossy as a Princess, Fairline or Azimut for example. It's simple, modern and angular but finished to a good standard.

I imagine the test will go into the March issue, out in the first week of Feb, but I'm more than happy to meet you at LIBS, John, and tell you more about what I found.

Cheers,

Jack

Thanks Jack. I saw the brief mention of this boat in the new MBY edition (the one with sq48 on front cover) and will await the full test next year, with interest. Yes, the interior needs some work but could be made ok I think. Will be delighted to hear more over a beer at LIBS -thanks.
Delta are listed as an exhibitor at Boot next year but they haven't said whether the 80 (or 88; I dunno which is the officially correct designation) will be there

 

[benjenbav]

To my mind that is a beautiful boat. I saw echoes both of Steve Dashew's "Wind Horse" and Steve Jobs' "Venus" and I guess the idea of people doing a double take as they drive along the Corniche past Villefranche is not a displeasing thought.

I wasn't too sure about the f/b. It looks small on #1 but I thought it looked a bit heavy on the p/shopped mock-up.

I didn't like the interior very much in the pictures and wondered if #1 had been built as a generic to show the space available without asking too many leading questions.

All imho, of course.

 

[larsolthof]

very good looking "rufty tufty" yacht.

 

[Jack Haines]

Thanks Jack. I saw the brief mention of this boat in the new MBY edition (the one with sq48 on front cover) and will await the full test next year, with interest. Yes, the interior needs some work but could be made ok I think. Will be delighted to hear more over a beer at LIBS -thanks.
Delta are listed as an exhibitor at Boot next year but they haven't said whether the 80 (or 88; I dunno which is the officially correct designation) will be there

Yes, they'll be there but the 80 (it is the 80, by the way, but the owner of #1 requested his to be called the 88 for his own reasons) won't be - just the 26 Open, 33 Open and 54.

 

[jfm]

Yes, they'll be there but the 80 (it is the 80, by the way, but the owner of #1 requested his to be called the 88 for his own reasons) won't be - just the 26 Open, 33 Open and 54.

Thanks Jack. Do you know if they have rights to show the "88" at any shows, and will they be? No point going to Boot if the boat isn't there, obviously. The obvious boat show contenders are
Gothenburg, 31/1/14
Helsinki 7/2/14
Stockholm 1/3/14
Oslo 12/3/14

Respect to the customer - getting the boat builder to change the name of the model is a customisation step I haven't tried yet I'm going to ask Fairline if they'll make me up some "80" badges