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

KevB said:
I realise it's only a drawing but it doesn't look to have a very deep V which may explain the high speeds and also why it doesn't appear to lean much whilst turning at "36" knots as shown in the picture below.

I know if I were turning my boat at 36 knots the port holes would almost be under water.
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This boat is not with a V-bottom hull, it is warped and designed for IPS. The turn in the picture is not the tightest, but regardless of how fast and tight you turn, the heeling is very near a "true turn". Within one degree, meaning you don't feel it, or that you can have things on the table that stays there...
 
Designo said:
This boat is not with a V-bottom hull, it is warped and designed for IPS. The turn in the picture is not the tightest, but regardless of how fast and tight you turn, the heeling is very near a "true turn". Within one degree, meaning you don't feel it, or that you can have things on the table that stays there...
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Can only guess at what the ride is like in moderate sea's at cruising speeds. Is it not uncomfortable?
 
KevB said:
Can only guess at what the ride is like in moderate sea's at cruising speeds. Is it not uncomfortable?
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I think thats a fair question, KevB, that deserves a better answer. Those were my thoughts too. Even though the Delta is a relative lightweight, the aft sections of the hull must be pretty flat to achieve that kind of speed but I am very happy to be educated as to how the boat can be both fast as well as comfortable
 
Deleted User said:
I think thats a fair question, KevB, that deserves a better answer. Those were my thoughts too. Even though the Delta is a relative lightweight, the aft sections of the hull must be pretty flat to achieve that kind of speed but I am very happy to be educated as to how the boat can be both fast as well as comfortable
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The hull is warped from 90 to 15 degrees, with soft curved reverse chines and strakes. As all hulls with triple IPS, there is a flat surface for the middle engine. Of course the hull is designed for the length and speed it operates in and is not supposed to make big jumps between the waves. Instead it should slice through the wave tops and reduce vertical movements for a smooth ride. It works pretty well....

D80 hull.jpg
 
Designo said:
there is a flat surface for the middle engine.
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have you never considered a twin configuration ?
I think that Volvo doesn't have a bigger engine suitable for that,
but there are other options,
and I think you would gain a bit on weight / power / efficiency ?
and have space available for a nice entry from a transom door, and space between the two engines
 
Designo said:
The hull is warped from 90 to 15 degrees, with soft curved reverse chines and strakes. As all hulls with triple IPS, there is a flat surface for the middle engine. Of course the hull is designed for the length and speed it operates in and is not supposed to make big jumps between the waves. Instead it should slice through the wave tops and reduce vertical movements for a smooth ride. It works pretty well....
Click to expand...
Fair enough. 15deg deadrise at the stern is about average for a planing craft, in fact maybe slightly 'better' than average. If you can trim that plumb stem bow down far enough to meet the waves in a head sea, she should be pretty comfortable
 
BartW said:
have you never considered a twin configuration ?
I think that Volvo doesn't have a bigger engine suitable for that,
but there are other options,
and I think you would gain a bit on weight / power / efficiency ?
and have space available for a nice entry from a transom door, and space between the two engines
Click to expand...

We have done the math with twin IPS1200 and it should have a top speed around 30 knots which is OK for many people. Regarding a transom door, It is how several boats have gone down. Even when you are going through a lazarette with another door. It is called human error, but anyway a reason to avoid it.
 
Deleted User said:
Fair enough. 15deg deadrise at the stern is about average for a planing craft, in fact maybe slightly 'better' than average. If you can trim that plumb stem bow down far enough to meet the waves in a head sea, she should be pretty comfortable
Click to expand...

I'm a fan of straight bows. They tend to cut cleanly through waves rather than raise the bow above them, so reduce porpoising quite a bit by comparison.
The example I've seen in action is on a 1949 built boat though, but I'm sure the characteristics haven't changed!
The boat in question doesn't have windscreen wipers and the owner was really worried he wouldn't be able to see anything.
But the boat cuts cleanly through the waves and gives a beautifully dry ride.
 
MapisM said:
Wow, Q.E.D. :)
If I may ask, why did you choose RINA? Mind, as an Italian, I'm not complaining about it at all....
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RINA's certification business is unusually global MapisM and they certify many boats with limited/zero connections with Italy. My boat has much RINA paperwork and certification
 
Designo said:
Regarding a transom door, It is how several boats have gone down. Even when you are going through a lazarette with another door. It is called human error, but anyway a reason to avoid it.
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do I understand this right ?
do you consider a transom door as a human error because of the risc of sinking the boat ?
 
MapisM said:
Lars, have you by chance calculated which sort of performance the boat could achieve with just two of those IPS1200?
I mean, not leaving the center one turned off, but getting rid of it altogether.
I suspect that with another weight reduction of almost 2.5 tons (and right at the stern), she could still be good for the high 20s, which is probably more than enough for many boaters.

And by moving the tender up on the extended f/b as per jfm drawing, you might recover all the valuable space now taken by the garage, going all the way down to the keel (well, almost), getting a fantastic engines accessibility and also a convenient passage through a proper transom door.

Just a thought, anyway.
But don't ask us how to do that, or someone might well take up the challenge and send you some cad drawings just for fun... :D
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MapisM, my understanding is that 2xIPS 1200 is indeed an official option for this boat, based on info from the marketing side. Problem is, and it is much more perception than engineering, it might kill the residual value.

My thinking as regards tender was to put it on the swim platform, btw, not up top. It would be a fairly nice 4.5m RIB
 
BartW said:
we have to avoid portholes then ?

we do a briefing before departure is that not common practice on a 80ft boat ?
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I am avoiding portholes too... But last sinking I heard of was a (I think) 42 m Baglietto anchored at the Pampelonne, where a swell from a passing boat entered from behind. Luckily it was shallow so it did not sink completely...

Here is a link with pictures from the event; http://www.dailymail.co.uk/news/art...--passengers-rescued-thanks-Simon-Cowell.html
 
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I used to work on a 43 m Heesen and passing wake from boats was a pain although we had a small canvas flap (only a foot high) that we raised when the transom door was open to prevent the larger wash. Mangustas charging about in Ibiza normally the culprits!

On most modern superyachts the laz is a wet room these days though.
 
Hmm, many non complainers will just buy another boat. Those that raise the issue probably care enough about the feature that they too will walk away if you cannot learn from feedback. Few or even none will put up with this type of response when spending 5meg.

How about you try to be a bit more accommodating in at least discussing the possibility? Many 'amateurs' on this forum have modified boats and had extensive modifications adopted by the major manufacturers.

You have tapped into, probably the greatest, instant, market feedback resource in the boating community for a designer and it is free. If you explore the possibilities here, you could win fans and probably customers. Or you can adopt the attitude that you are 100% right, in which case there is not much point in coming here. Go check out the VdV thread, they have had great feedback and coverage, same is true of several of JFM's Fairline semi-custom builds and a recentish Princess build.

Just my 2c as a 10yr observer on this forum.
 
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