Boat in build pics (Squadron 78)

Hurricane said:
What do you recon your max displacement speed will be then?
I recon ours is about 9.5 knots.
At 10 knots we are burning about 25 litres per hour – per engine.
That’s about 1.3 gallons per mile or .75ish mpg.
So your figure of 0.8 mpg could be about right.

I always take my figures from the engine management system which is, of course, only theoretical but I have also carried out lengthy tests to prove these figures. I didn’t want to set off into open sea pushing beyond the planning range without knowing the actual fuel consumption at displacement speed.

We carry 4000 litres which gets us 300nm in good conditions at planning speed. I believe that this is the range that Princess target on all their boats. Last summer we did several runs to the Balearic Islands without refuelling. The crossing is about 100 miles and by doing some displacement and some planning speeds we can last the whole cruise without refuelling. I recon we can run for just over 700 miles at 10 knots.

Not sure about the 18 knot option.
Our engines definitely have a longer range at 25 knots than 22 knots. I’m sure that’s because at 22 knots, the second stage turbo hasn’t yet “switched in”. But is there an efficient planning speed below 20 knots – never really tested it. We either run at planning speed of 25 knots or just below 10 knots in displacement mode.

Anyway, can’t wait to see your new boat in the flesh – we are going to try and get to the show on the preview day – hope to see you then.
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Mike I dunno till I drive it but I'd think you start pushing the bow wave and losing the benefit of d running at say 11kts. Thanks for your data - my 0.8mpg guess is about right then. I will of course get my real data from the screens as soon as I start using the boat. Interesting about your 22/25kt thing - the two stage turbo design of your lovely MTUs
Yup, see you at show on preview day
 
petem said:
JFM, when you get the chance can you video the stabs at anchor because I find it hard to envisage what they do to keep the boat stable?

Pete
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Yup willdo. Actually Fairline have a vid from the actuator side already, but I don't have the file off them yet. Pete, the stabs only stop rolling, and they do that by exerting a torsional force on the whole boat, rotating it about its longitudinal roll axis. At anchor they do this just by flapping the fins, very fast. If, say, the boat's sensors detect that the boat is beginning to roll clockwise (looking at stern) ie port side is lifting on a wave, they tell both fins to flap clockwise (looking from above) fast. The fin motion makes the boat try to roll anticlockwise looking at the stern, or tip port side down. That counteracts the roll. That's all they do, at anchor. They don't stop pitching (bow lifting and dropping on waves)

Underway is similar, but they have the ability to do a limited amount of anti-pitching by creating torsional force about an athwartships axis, but it's pretty limited and their main effect is to cancel rolling. At speed of course this means the boat corners flat, which feels weird

But yes I'll try to get some vids with underwater camera next summer
 
I have visions of squads of forumites at the LIBS running in co-ordinated fashion from side to side across jfm's decks, while others peer transfixed at the underwater flappy bits doing their job of stopping the whisky sours falling over on the flybridge. :)
 
jfm said:
Yup Nick, have been in Ipswich doing last minute tweaks (cushions etc) to boat before it leaves for LIBS.
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About bloooody time! There I was constantly looking to all horizons for a large white thing blasting along on the way to LIBS. Get there, still nothing. Hmmm? Get home, switch on PC, there you are, still in Essex, arranging cushions! :) Congrats, she looks fabulous, absolutely love the internal stairs.
 
jfm said:
..........They know they worked though because the boat (wierdly) cornered flat even at high speed.

So, all good. I'll report in more detail later of course :)
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Yup, that does take some getting used to and it will make you feel you are moving slower than you actually are, be careful. :-) As this is the first Sleipner I can't be absolutely sure but I would be quite confident that if you did push the boat enough in a turn (say 28kts + with full lock) then it will lean in the turn, at full power in the turn, it will be almost the same as having no stabs, the fins are simply not powerful or large enough to hold back those levels of dynamic force; But that's a good thing, best of both worlds when you want it. :D
 
jfm said:
...........................Come resale, when there are 1/2 doz Y80s or Sq78s for sale at any one time, I'm confident mine/MYAG's will sell the easiest. Why wouldn't a buyer pick the one with stabs, all other things being equal? And these size boats can be slow to sell, so the "cash liquidity" benefit of such a big distinguishing feature like stabs is part of the analysis, as well as the seakeeping benefits. All imho of course
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Maybe for yours JFM, out of the 25 or so Y80's sold so far, not one has been ordered without the TRAC STAR system. Unfortunately therefore, having them won't help me when I come to sell! :(


jfm said:
I doubt Fairline will offer stabs on boats other than s78 and its replacement, but I don't know. The next boat down, 65, is a lot more production line than the 78 so the time and one-offing to fit the stabs might not work in terms of production planning and timing. I don't know for sure. If another customer asked for fins on s78 I'd expect Fairline would say yes without hesitation. Incidentally though, demand isn't that strong; they have offered seakeeper gyros on sq78 for over a year and yet only 2 customers out of say a dozen boats have ordered them. That might be partly price: stabs = £100k
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I think stabs definately have a future, and in smaller boats too. ABT already make a system for boats at 16m/50ft and could even go smaller. As volume increases the prices should come down, also with Sleipner now in competition, it can only mean good news for buyers. With respect to the Seakeeper gyros, I am not surprised the take up has been small, I wouldn't have them either, for performance and space reasons. Now that Fairline offer a fin solution, I would expect the demand to increase considerably.
 
petem said:
Cheers. So they rotate at anchor? I wondered if they turned upward / downward and flapped back and forward. I assume they are sufficiently under water not to make a splash?

Pete
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Pete, all they EVER do is rotate about a fixed axis. They're the same, mechanically, as a pair of (very big and powerful) rudders, but with the axis perpendicular to the hull face rather than vertical, so they can create a vertical component in their lift/dive forces
 
petem said:
Can you set them so that they allow the boat to roll naturally when cornering?
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Theoretically possible if you can feed cornering data to the computer, eg rudder angle sensor or a gyro input. But the gyro input might get confused with wave-induced motion so rudder angle input is probably needed. No-one has bothered to do this afaik
 
sarabande said:
I have visions of squads of forumites at the LIBS running in co-ordinated fashion from side to side across jfm's decks, while others peer transfixed at the underwater flappy bits doing their job of stopping the whisky sours falling over on the flybridge. :)
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Actually Sarabande, you can unscrew the black box containing all the gyros (it's under the bed in master cabin) and shake that about, whereupon the stabs will move violently :-)
 
MYAG said:
I think stabs definately have a future, and in smaller boats too. ABT already make a system for boats at 16m/50ft and could even go smaller. As volume increases the prices should come down, also with Sleipner now in competition, it can only mean good news for buyers. With respect to the Seakeeper gyros, I am not surprised the take up has been small, I wouldn't have them either, for performance and space reasons. Now that Fairline offer a fin solution, I would expect the demand to increase considerably.
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Ah yes I forgot that MYAG. You are right - the manufs are aiming now at creating a fin stab market for 50ers. Sliepner are in that race, offering small fins

I totally agree with you on seakeeper gyros. I just wouldn't have them. The downsides outweigh any upside imho. I'd rahter have an 80er with no stabs than seakeeper gyros
 
jfm said:
petem said:
Can you set them so that they allow the boat to roll naturally when cornering?
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Theoretically possible if you can feed cornering data to the computer, eg rudder angle sensor or a gyro input. But the gyro input might get confused with wave-induced motion so rudder angle input is probably needed. No-one has bothered to do this afaik
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Not that I see any reason for that - aside maybe from testing the hull - but keeping them turned off and center locked would be a much easier way to achieve pretty much the same result... :)
 
MYAG said:
I think stabs definately have a future, and in smaller boats too. ABT already make a system for boats at 16m/50ft and could even go smaller. As volume increases the prices should come down, also with Sleipner now in competition, it can only mean good news for buyers. With respect to the Seakeeper gyros, I am not surprised the take up has been small, I wouldn't have them either, for performance and space reasons. Now that Fairline offer a fin solution, I would expect the demand to increase considerably.
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Trac stabilizers have been fitted to relatively small displacement boats for years so I guess the transition to smaller planing boats would not be a major step for them. Do you know if the fins and the actuating mechanism are beefed up for planing boat applications as I guess the potential forces on a stabiliser fin are many times higher at 30kts than at 6kts?
Whats the performance issue with the Seakeeper system? Is it the start up time?
 
jfm said:
No I just made it up. Conservative guess I reckon, though displacing 55t at d speed might mean it is correct! TBH, there isn't a spec range for the boat. It is what it is, and I'll find out when I drive it and read the Garmin screens at various speeds. I asked for the extra fuel tank but my priority was to not make it so big that it spoiled the m/cabin by creating a too wide or too-high bed, so that's what determined the 1500 litre size of the fuel tank. The bed in my m/cabin is 5'3" or 160cm wide, which is bigger than official "king size", slightly, but looks very ok

Fairline have built one other sq78 with a 3rd fuel tank, now for sale here but the customer for this insisted on 2000litres and this made for an ugly (imho) wide bed that you can see in the pics at that link. The width of the bed spoiled the cabin imho, see photo 4, (and the boat in general had an interior I just couldn't get along with, but when you offer a custom product you do get some requests that are particular to the customer concerned!)
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According to my SWMBO who knows about these things coz she's constantly planning how to spend more of our money on our house, 5' is queen size for superior bed makers and 6ft is king size. Its only MFI that call 5' king size!
Anyway 5' 3" is plenty wide enough IMHO. Yeah bed in that Sq78 seems like it takes up the whole cabin floor which is stupid for an extra 500 litres of fuel. Out of interest why cant the boat be sold to US buyers in US waters?
Going back to the fuel consumption thing, if the d speed fuel consumption is anything like other boats, the mpg will be much higher at lower d speeds, say 6-7kts than at higher d speeds like 9-10kts which is getting close to the max hull speed
 
Awesome, jfm. Just one thing...

IMG_1443.jpg


As this picture clearly shows, Match is much wider than the dock and the "on the water" shots must be of a sister ship; yours being stuck in Ipswich. :D
 
Deleted User said:
Going back to the fuel consumption thing, if the d speed fuel consumption is anything like other boats, the mpg will be much higher at lower d speeds, say 6-7kts than at higher d speeds like 9-10kts which is getting close to the max hull speed
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Mike
What are you saying?
I've only really noticed the massive drop in fuel consumption from planing to displacement.
I didn’t think there was a huge difference once you get below or into displacement speed.

Sorry jfm - thread drift - don’t want to increase the size of this thread unnecessarily!!:)
 
benjenbav said:
As this picture clearly shows, Match is much wider than the dock and the "on the water" shots must be of a sister ship; yours being stuck in Ipswich. :D
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I think you've hit on something there bjb. When the test team reported back to jfm that the boat was incredibly stable, I think they might have been referring to the fact that it was wedged solid in the dock rather than to how the flappy bits were working :eek:
 
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