What's going to happen ? (Shaft v Outdrives)

Re: What\'s going to happen ? (Shaft v Outdrives)

The Nordwest 390. I quote MB & Y, March 2005.

“The 390 boasts the raucous option of outdrives. It’s a feature that not so much rewrites the rulebook but shreds it utterly. The twin D series duoprops turn mild manners into what is the best handling and most smile inducing drivers boat in its class.

The big book of boat design, the one that has just been shredded, decrees that past 30 odd feet the extra height of the flybridge requires a bit of iron under the hull to keep the ride manageable. Most builders go along with this, and Nordwest offer a shaft version of the 390. But once you’ve tried the outdrive boat you won’t want to consider the extra cost of shafts.

For lower speeds and close-quarters manoeuvering the difference compared to shafts is tiny. The boat tracks straight and true, and you can run on one engine with very little offset at the wheel. Our test boat came with bow thruster but it didn’t need much handling help. The boat can be spun and sloted into gaps with ease, and as the speed increases it just gets better.

There are efficiency gains too. Running at 2300rpm and 21knts, the fuel rate hovers around 14gph. Increase speed to 30knts and the rate goes up to only 20gph. The 390 returns a minimum 20% fuel saving over its competitors, in some cases over 30%.

But again I have to come back to the economy of the thing. A boat of this size and quality running at 31knts at almost 1.6mpg is just as thrilling as the handling. If this boat had been running at the same speed on shafts the return would have been under 1.0mpg, which is why many of us buy sport cruisers at this length. Now we have a flybridge choice. “

I quote selectively from their verdict.
“The 390 leaves you wanting for nothing – performance with economy, style with substance, it’s all there. The handling is a revelation, an utter triumph”. There simply isn’t another boat in this market that handles sea conditions and Chancellors of the Exchequer equally well. The increased cruising range this superb economy delivers-around 25% more than its peers-can be enjoyed within a beautifully finished mahogany interior that boasts three cabins and a specification which puts most to shame. I’d bet my mortgage that this boat will still have you feeling proud in years to come. The end result is both compelling and utterly charming”.

If I had the 275,000 quid I know what boat I would be buying. In fact second hand you might get one for 220,000. Give it a couple more years, a bit of saving & who knows ?
I know this is an expensive boat but it proves (to me anyway) that technically, outdrives, great handling (low & high speed) and class leading economy can be combined in a 40ft boat. How far behind will the competition be ?

P.S
I have nothing to do with Nordwest !
 
Roll up Roll up .New mugs always welcome.

The independant journalist eh.He/she will walk away from the boat to his type writer,via the bar,never having to put his hand in his own pocket to pay for the constant up keep of those daft lumps of metal with their complex combination of bearings, oil seals,gears,shafts,hydraulic pipes,pumps,electric motors and relays, not to forget universal joints all dangling in the drink.An thats when the thing is new,give it a year or two or mebbe twenty and then see how much of the worlds resources it costs to keep the nasty things going.We all could wax lyrical about the wonderfulness of assorted exotic motor cars,but wait until you actually run one. In the real world,avoid at all costs. /forums/images/graemlins/grin.gif
 
Re: What\'s going to happen ? (Shaft v Outdrives)

My last boat was a Doral Elegante which was 33' long with twin KAD300's on shafts (V Drive). It would cruise at 22-23 knots at 3200 RPM using 80 l/hr, and 32-33 at WOT. With full tanks and 2 people on board it needed the tabs down to get on the plane, and in the marina I never managed to master the "superior handling", and would dread the last few minutes of every cruise. This boat is also available with outdrives for the same price.
My current boat is a Doral Boca Grande which is 36' long, 2 tonnes heavier, with twin KAD300's with outdrives. It cruises at 26 knots at 2500 RPM using 60 l/hr, and over 40 knots at WOT. Fully loaded it takes off like a scalded cat, and the big grin is back on my face. The marina is now no problem for me, and I have managed to park it satisfactorily every time, in a far more relaxed manner.
Over a 100 mile cruise from Southampton to Torquay the shaft boat used 360 litres, and the heavier outdrive boat uses 230 litres, The journey time is less, and the noise levels reduced by lower revs, and underwater exhaust. the handling of the outdrive boat is in my opinion far superior, and the smile factor 100% greater.
If because I have gone back to outdrives makes me a "Non Serious" boater, given the above true facts and observations, then you can keep "serious" and I will keep happy and contented.

Terry
 
Re: What\'s going to happen ? (Shaft v Outdrives)

100 MN
Shafts = 360 litres
Outdrives = 230 litres
Actual figures. See reply further up for full story.

Terry
 
Re: What\'s going to happen ? (Shaft v Outdrives)

Don't want to turn this into a red diesel debate, but the whole point is we already agreed, if nothing more happens diesel will go up in price.
 
Re: What\'s going to happen ? (Shaft v Outdrives)

Outdrives are far more efficient than shafts. Take a sunseeker portofino 400 as an example. With KAD42's (230 BHP) on legs will do about 28-30 knots. The same boat with twin TAMD71's (370 BHP) on shafts barely manages the same. 280 extra bhp but less speed, that's a lot less efficient!!
 
Re: What\'s going to happen ? (Shaft v Outdrives)

What are the weights of the engines, if one is a lightweight high pressure turbo, and the other a heavy detroit lump , then this relative difference is to be expected. In any case, who wants the maintenance nightmares?.
 
Re: What\'s going to happen ? (Shaft v Outdrives)

There are very few boats that have fitted both options making comparisons difficult. However I happen to have some MB&Y stats comparing the Sealine S41 with the S43 (same boat except the 43 has shafts).

Shaftdrive S43
twin 420hp Yanmar 32.0 knots, helm db 82, wt 9.5t, flat out gph 39.9 (0.80mpg)

Outdrive S41
twin 300hp Mercruiser 30.1 knots helm db 81, wt 8.9t, flat out gph 27.3 (1.10mpg)

Which makes the outdrive 37% more fuel efficient (based on mpg)
That's quite a saving!
David
 
Re: Roll up Roll up .New mugs always welcome.

By that reckoning a Porche 997 Carrera one of the world's finest sports cars with a top speed of approaching 180 mph is a pile of junk.

Ran a 911 never gave a moments bother, ran a Discovery for a year and it fell apart !.

Time to get real, times have moved on, technology has moved on, only some people refuse to be dragged into the 21st century. /forums/images/graemlins/confused.gif
 
Re: What\'s going to happen ? (Shaft v Outdrives)

Good comparisons. (In my view) Outdrives by a mile.
Some people posting on this thread doubt the efficiencies of outdrives.
So I assume you for one agree with my original theme that in the future people may be swayed away from shafts if the diesel price trebles! /forums/images/graemlins/frown.gif
 
Re: Roll up Roll up .New mugs always welcome.

Thort you would cotton on to that one .It took a mere 60 years for the computor to come along to tame the evil tail handling beast that was the Porche and it costs a fortune to remove the handling from the control of the driver and give it to the microchip.Colin Chapman got it right from the start.Keep it cheap keep it simple and keep the C of G in the middle where it belongs.You can also reinvent the wheel as often as you want,give it a technical new name and a posh ad campaign to boot,lets call it IPS for instance,but its still outdrives with a whole new bunch of problems designed in............. /forums/images/graemlins/grin.gif
 
Re: Roll up Roll up .New mugs always welcome.

[ QUOTE ]
lets call it IPS for instance,but its still outdrives with a whole new bunch of problems designed in............. /forums/images/graemlins/grin.gif

[/ QUOTE ]

On that I will wholeheartedly agree - you can't even tilt IPS for shallow water or to take the ground or to clear the props.....coupled with an article I found that showed in aircraft terms pusher props are more efficient than tractor props....why IPS again????

/forums/images/graemlins/shocked.gif
 
Re: Roll up Roll up .New mugs always welcome.Get your IPS here.

And summat else.Most conventional modern shaft boats have tunnels.(Ahem even lifeboats).Them natty complicated little egg whisks have to have clear water all around that means they have to stick down further below the bottom of the gin palace and draw more water and that puts em even further in harms way.
Ooo and no nasty keels allowed either cos will stop boat going sideway,er you did want your boat to go sideways sir!
 
Re: Roll up Roll up .New mugs always welcome.

Er, them there old Lotus things were stuck together with chewing gum and as about as reliable as a chocolate fire guard. So you would rather drive one of them than a new 997? better make sure your AA subs are up to date.

Looks like logic can't convince you, on the other hand if you were hit by a bus and left horribly disfigured I suppose you would rather be hacked about with a carving knife rather with micro surgery, same theory same practice only one leaves you looking like the aftermath of a horror movie the other gives you a least a chance of looking normal again. Its called progress and advancements in technology.

IPS will make its mark on the boat industry, no doubt, once you have driven one everything else is old hat, you jump back on a traditional shaft drive and think whats happened, did someone turn the power off? Sure there are drawbacks but I think many are making a mountain out of mole hill just for the sake of traditionalism, suppose just like many say, 'ah it was better in the old days', no thanks, give me the 21st century any day it may have its faults but at least we all live in reasonably warm houses with inside toliets.

Me thinks you're just winding me up now, good laugh /forums/images/graemlins/grin.gif, thanks, can't believe you can not appreciate new technology, I am sure you are a very intelligent bloke, got me going for a minute though /forums/images/graemlins/blush.gif
 
Re: What\'s going to happen ? (Shaft v Outdrives)

If it "only" doubled to £1/l in this example the weekend jolly would "only" cost £460 on outdrives or £720 on shafts (assuming calm conditions)
If I still had shafts this particular trip would become a distant memory, but with outdrives it is still doable occasionally.
 
Are well thats most of the East coast sans IPS.

So when I park my future boat with its nice "Snap Off" (TM.)drives,should I hang around to watch the drives come up through the bottom of the boat on my drying berth or just pop back later with a few salvage pumps and a repair kit.. /forums/images/graemlins/wink.gif
 
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