I have really enjoyed working on my boat.... But.... Fancy something bigger....

[Latestarter1]

Any personal experience or just hearsay?

Just a bit....All shapes and sizes.

My first marine re-power project was in 1987 4 Ex US Navy 65 ft personnel boats with twin DD12V71 400's repowered with Cummins NTS 855M 400 for Port of Beira. Oil and filth left by the 12V71's took dockyard gang two weeks to clean up. In service fuel saving documented to be over 20%.

Dutch Barge with DD4-53 re-powered with Cummins 6B 120 10-15% fuel saving dramatic lowering of noise level and zero lube oil consumption. Could not bear to part with the little 4-53 for years as it was such a sweet little motor.

50 ft Hatteras twin 8V92TA 550's owned by a pal of mine, real pretty boat.
Re-powered with Cummins QSM11 715's.

Exactly one tonne of displacement saved........WOT speed with 8V92TA's 21 knots burning 19.2 gallons/hr
Re-powered WOT speed with QSM11's 26.6 knots 86% engine load 16.6 gallons/hr with 20 knot cruise @ 58% engine load.

Engine room on Hatteras now stays spotless.

Long before 1987 project managed production truck originally installed with 6V71 to NTE 290 in order to provide acceptable fuel economy, 6.2 mpg with 6V71, 7.8 mpg with NTE 290 on same duty cycle. Out of interest parts count 6V71 65% greater than NTE290.

Finally California replacement grants are based on in service fuel returns from re-powered vessels coming in around 24%, sample group over 500 vessels. All FACTS available under Freedom of Information.

 

[Robg71]

Thats some saving.....
Cheers LS

 

[Bertramdriver]

Impressed! As a matter of interest what would be your top 5 leisure engines from the 80's and 90's? I ask because so many of us less than wealthy mobo owners tend to buy older boats with a variety of engines. Practical experience is worth a damn sight more than theory.

 

[Divemaster1]

DD 2 strokes does have a rep for leaking a bit, and the V's in particular does have a fair bit of more moving mechanical parts when compared with a 4 stroke... and the extra complexity in the block does come with additional weight of course .... and they were constructed to last.... Of course more moving parts come with extra mechanical friction etc., which translates into fuel burn...

However, and as you know, I have looked at replacement cost and from a financial perspective only, I struggle to justify it.... (know the environmental piece, clean engine room and noise levels also come in).

Let's say I want a pair of 430 HP Cummins CTA's @ about £23K each + install to replace my DD 6/71's ... and that I will save 25% in fuel cost... (I'll use round numbers)

I'll use the boat 100 hrs PA and burn roughly 150L per hour ... that is 15,000 L of fuel : £1.20 / L = £18,000

25% savings = £4500 ... so roughly a 10 year payback... replacement for commercial use and above 500 hrs PA I can easily understand....

....and I also note that this savings are for new engines (21st century), not 4 strokes of 1980's era...

 

[rustybarge]

...and I also note that this savings are for new engines (21st century), not 4 strokes of 1980's era...
Last edited by Divemaster1; Today at 19:15.

So are modern diesels with all the electronic gizmo's any more fuel efficient than the 80's and 90's 4 str. versions?

Am I right in saying that the electronic efi for diesels was introduced to comply with EU emission regs, but only works at low revs and does not result in better fuel economy at cruise settings?

Of course from a mechanical perspective twin cam 4 valve diesels are about 10% more efficient than the old 2 valve ones.

 

[Divemaster1]

So are modern diesels with all the electronic gizmo's any more fuel efficient than the 80's and 90's 4 str. versions?

.

Someone techie will come along to explain I guess.... but from a non-technical perspective, I guess that in principle "no" .... diesel have got a given calorific value and you cannot practically get more out of a specific volume irrespective I guess (assuming clean combustion) ... looking at the D3 to D16 series from V... they burn between 205 - 242g/kwh, http://www.volvopenta.com/SiteColle...rochures/English/Product Guide Commercial.pdf

...the upper end which is pretty similar to my DD's when in tune ... The problem with older engines, likes of my DD's is that they go out of tune, but still operates under less than ideal conditions.... if an injector (or several) is out, and squirts excess/to little fuel in, then the engines smoke, or do not produce the power ... but still run... all be it with a poorer combustion .... a modern engine with electronically mananaged injection, will have much lower tolerances and I believe will "manage" the fuel to be injected within the given parameters, and thus not allowing injection of excess fuel which a mechanical engine will permit. Now that is what is different with the DD's ... you need to listen to them, how the fire, how they react when power is loaded on and learn to understand when they are starting to go out of tune ... (or live with the excess fuel burn). The 2 stroke DD's are commercial/military based engines, so once running you do not wish them to shut down until you have to (or safe to do so)... then you can do your tune-up... but as long as you give them air, fuel and lube oil after they have been fired up, they will run until you switch them off, seize, self-destruct etc.

Rob here clearly stated that his engines (Sabre's I believe) ran "well" when well out of tune, but after a injector change/clean, they behave much better / cleaner and his boat now performs as if she was new... but I bet that if you were to measure fuel consumption before the tune-up, she would have burned way above 240g/kwh... and as always, fuel consumption is all relative to how you use the boat.... 2 stroke DD's like to work hard, and they have a lot of mechanical friction (hp used on turning cogs, shafts and lifting rockers), but don't like idle for hours on end.... 4 strokes are more forgiving.. Will shut up now....

 

[Robg71]

No need to shut up Alf.
There are a good amount of people who can rattle on for hours and lots of us will listen... Yourself, volvo paul, latestarter, jfm, and you know its all good sound advice.

 

[Robg71]

The more i look at the camargues, the more i go back to looking at the mustiques....

I can feel another project coming on

 

[longjohnsilver]

The more i look at the camargues, the more i go back to looking at the mustiques....

I can feel another project coming on

What happened to the Sunseeker you were keen on a few weeks back?

 

[Bandit]

I have little experience of DD, a chap I was talking to this week had DD,s in a 39ft classic Italian Boat 40 yrs old took out the DD,s and replaced them with new Yanmars of slightly more hp and saved over a ton in weight in a 10 ton boat.

If you are looking for a holiday home and spending more time in Jersey living on the boat a fly bridge gives you an extra room to live in with a view, I would look at 1980's Princess and Fairline.

Also engine size a pair of 500hp in a larger boat at 23 knots will burn 60pc more than a pair of 300hp in a smaller boat at the same speed as a rule of thumb.

The are 1 or 2 sweet boats that work in every manufacturers range Fairline Turbo 36 or Sedan 36' Princess 45 original , 1990's Fairline 38 etc.

 

[Robg71]

I was quite taken by the princess 45 on the block by boat works in SPP.

I am still waiting for info, and contact from my local broker, and a n other broker.

LJS. Nothing wrong with the mystique I saw, apart from what was mentioned in the thread
at the time. It's a possibility. Its still for sale, and i am still waiting for more photos and details.
I need to speak to my broker about putting mine back on the market.
I really don't want two boats...

 

[MRC]

What about going mad and looking at something big. Renegade 60 or early predator 58/60s?

Ones that need the work as you clearly enjoy tht part.

 

[Robg71]

As that's a little too big. Lovely as they are, I still need to afford to put fuel in them.
50 ft is my absolute limit, but actually I don't think I need a boat that big. And they are out my price range

 

[Robg71]

Whilst looking at the princess420 and 45, what is there cruising speed. Certainly on the sedate side???

 

[Bandit]

Princess 45 1984 2x 306 hp top 24.5 so cruise 20 to 21knots

Princess 415 1986 2 x 300 hp top 26.5 so cruise 22 to 23 knots

Fairline Turbo 36 2 x 306hp probably top 25 so cruise 20 knots

Fairline 36 Sedan 2 x 370 hp top 29 knots so cruise 22 to 25 knots , aft cockpit version of turbo 36 excellent hull I had one repowered with these engines.

I have the boat reports from MBY and MBM for the above except Sedan plus New Princess 45, Princess 435, Pricess 412, Princesss 414 and White water Wolf 46 if you either let me know and come to Guernsey you can pick it up or i can post it it if you Pm or email me an adress.

I think the Fairline Turbo 36 would be a good boat for you good outside driving position, no ladder all stairs, two good cabins and no canopys, and an excellent sea boat also easy to handle with one person.

 

[Erik C]

Found this on YouTube

 

[Robg71]

Sorry, can't watch videos, not enough bandwidth on work Internet..

 

[Erik C]

Maybe you can watch this.

http://www.jdyachts.com/listed-boat/view.php?id=965

 

[Divemaster1]

Rob,

Suspect you are looking for the holy grail ... more space, equally as fast, similar fuel cost, simplicity of shaft drive... and giving you a challenge.... difficult one that...

Shaft drive usually means more friction, (more noticable the faster you go) so more hp needed to move boat, and downward angle of shaft is not ideal as thrust is not directly in direction of travel....

So if you want shafts, size and speed, you are into surface drive or water jet territory..., but usually that means newer & big = $$$$

How about two curve balls as options ? just to muddle the water ... both of which are a compromise .... two cabins, flybridge or open, and a unique configuration which combines shaft drive simplicity with surface drive efficiency .... and cruising in the 30 knot range ??

Compromise is that they will be older, Italian and not as sleek as a Sunseeker...

Italcraft made the Aermar 36 and M74 (51ft), which had a unique, efficient drive system in the early to late 80's ... the 36 did nearly 40 knots with 2x300 Aifo

good news is that you can get them "cheap"...

http://www.mondialbroker.com/Italcraft/36 aermar fly/296438?K=SRC
http://www.yachtworld.co.uk/boats/1986/Italcraft-M74-2311718/Cyprus

 

[Robg71]

Thanks Eric and Bandit.
Yes, i have looked at the fairline 36
Im still not sure i want a flybridge yet. If im,honest, i need to do much more looking.
The biggest bugbear for me at the moment, is lack of space, and the fact i have to climbnover the aft cabin to get on or off.
As daft as that sounds, it drives me potty.
The extra or second permanet cabin would make life much easier for when family and friends stop.
I love the wind in your hair feeling with mine, and looking at the specs of anything newer, they are all going to be slower as the weight jumps up greatly from mine, listed at 6500kg. Mustique for example is around 12500kg, for an extra 6 ft...
No wonder mine does 36knots on 660hp. As apposed to32 knots for approx 900bhp.
I think alf maybe close, but i dont think there is a holy grail. Well maybe, just not for my budget
So need to spend wisely or be prepared to sit and wait.
Yet again though, i would sooner buy another project, and do what i have done again with Clymene.
That way it spreads cost as well, and you get a new interior etc etc..

If, i was going to be really stupid, i would build one of these......

http://www.bonitoboats.eu/downloads/files/1023-AL1400FAA4-7-k4t.pdf

How about that in aluminium.... I have the fabrication skills..... My woodworking is not up to much though...

Long distance, plod along across the north sea to norway and back.... Etc etc etc...
More space than you can shake a ****ty stick at.... Comfort, slow...
Thats the worst thing.... Need to remove the petrol head mentality, and i'm not sure i am ready for that just yet....
Find me a mustique for 20 k and we can bolt some 500bhp monsters in it hahaha...
I do love the idea of a plodder, semi displacement. And actually, if it did 12 to 14 knots for a larger boat, that drank a lot less fuel, than has its own appeal.
Decisions decisions