another idiot with mad ideas, new boat build

[MapisM]

(MapisM may not agree and may recommend ABT thrusters so you'll have to weigh the evidence: he says Sleipner have a great future behind them but I'm confident those words will be food quite soon )

Oi, we were discussing stabs technology, not thrusters, when I said that.
I'm not so interested in thrusters, that's stuff for sunday boaters. As is the AnCam, needless to say.

 

[MapisM]

But the big issue is shorepower. On a boat this size you will invariably get only single phase 230v shorepower. Even on a 25m berth you only get 3ph 50% of the time in my experience, but on say an 18m berth it will always be single phase.

Agreed, that's a point to consider, but my experience isn't so black and white.
By and large, I'd say that in 2/3 of the berths where I've moored in the Med 3ph sockets were available (and I mostly got 18m or so berths).
Even in my home marina, which is pretty close to Africa in more ways than one, 3ph is available everywhere, ffs!
Funny to hear that this can be a problem in Antibes and the likes, where btw the cost is a multiple...!

 

[Robg71]

Oi, we were discussing stabs technology, not thrusters, when I said that.
I'm not so interested in thrusters, that's stuff for sunday boaters. As is the AnCam, needless to say.

you two having a dig at each other

thanks for the info M
I was looking at a minimum of 2500 litres. but bearing in mind your is a different kettle of fish.

just checked up on aquastar 48..

Engines 2 x Volvo D9
Fuel 2,200ltrs
Range 450nm @ 10knt
Cruise 18knt
Max 26knt


do the raggies really overtake you
i bet they love that

 

[jfm]

Oi, we were discussing stabs technology, not thrusters, when I said that.
I'm not so interested in thrusters, that's stuff for sunday boaters. As is the AnCam, needless to say.

My thrusters and AnCam work very well Monday to Saturday, but yep you are right they work even a bit better on Sundays

As regards fuel, Rob the FairPrinSqueeker boats often have range as low as 250nm at 20kts (though some of their models have bigger range), but they build interiors that sell at boat shows and trade less fuel for more cabin space. If you are custom building I would try to fit some sneaky tank volume into awkward spaces and get 600nm at 20knots. So see if you can get 3500 litres on board

As regards gensets, Rob I think you are worrying too much about having too large a genset and running it at 60% load. In my book, you shouldn't worry about that. I'm more interested in not having too small a power output for the peak loads i might want to apply for say 10% of the time. What's the worst that can happen with a too-big genset? Slightly glazed bores at 5-10,000 hours? That's 10++ years away, and you can just pull the whole diesel engine out through the engine room door and buy a new one for 4 grand, job done. Get the Onan 17.5kva single phase. Has a 2.2 litre Kubota engine, soundproof box, all electronic control, accepts autostart, lovely 1500rpm, delivers 65 amps @230v 50Hz easily, dead easy to service (everything is at the front), best in class.

As regards single vs 3ph shore supply, that's interesting comment MapisM though I would suggest 2/3rd success rate isn't enough. I would say that unless you have say a 95% confidence of getting 3 phase shore power in a 15-20m berth then I still rest my case that it would be a bad idea to build a 3 phase boat. By the way, there are plenty of berths in this size category with the red 3phase shorepower sockets, but only one of the phases is live, and I'm wondering if you are mixing things up on that point? Sorry if telling you how to suck eggs. I cannot think of any production 18m boats that have a 3ph environment on board so I cannot see why marina operators would provide 3ph power. They do use the dark red 3ph plugs, as I say, but that is not the same thing

 

[jfm]

just checked up on aquastar 48..

Engines 2 x Volvo D9
Fuel 2,200ltrs
Range 450nm @ 10knt
Cruise 18knt
Max 26knt

A big drawback of Aquastar 48 is its too small range. 450 at ten knots is pathetic. Don't copy it! Aquastar do some things quite well but they get plenty wrong - but that would be another thread

 

[Robg71]

For a twenty knot cruise, we are looking at pulling 600hp.
Alf had a calculation somewhere for fuel consumption if I can find it again.

My goal for range was for comfortably across the North Sea. Without having to go to Peterhead or Lerwick to do it,

 

[JerseyDiver]

Aberdeen - Bergen 300nm

 

[Robg71]

How about from the centre of the universe, Hull

 

[jfm]

For a twenty knot cruise, we are looking at pulling 600hp.
Alf had a calculation somewhere for fuel consumption if I can find it again.

My goal for range was for comfortably across the North Sea. Without having to go to Peterhead or Lerwick to do it,

Absent accurate engine data I use 0.2 litres/hour/hp, as a ballpark figure. 600hp is 120 litres/hour by that measure (which feels about right, very roughly). At 20kts that is 6 litres per mile, or 1.3 uk gallons per nm. The 3500 litres i suggested, with 20% for reserrve and genset burn, is 2800 "effective" litres which is 470nm range. Hence, as per above post, I reckon 3500litres is a great target tank size, if you can do it

 

[JerseyDiver]

looked on google and navionics for 'Hull' but still searching ??

Grimsby Bergen 450 NM
Grimsby Stavanger 400 nm

At 20 knots that is a day at 10 knots 2 days.........not a trip every shift I guess but maybe 2 - 3 times a year ??? Or for relocation due work etc ie if your shore based building something etc ????

 

[Robg71]

That's the plan. I Love Scandinavia. Apart from the prices.
Grimsby is fine

Many thanks for calcs JFM.
Have sent instructions to holland. No reason why we can't carry that much as all tankage is custom made.
Plenty of place to hide them.

 

[jfm]

looked on google and navionics for 'Hull' but still searching ??

Grimsby Bergen 450 NM
Grimsby Stavanger 400 nm

At 20 knots that is a day at 10 knots 2 days.........not a trip every shift I guess but maybe 2 - 3 times a year ??? Or for relocation due work etc ie if your shore based building something etc ????

They are long days! Longest I've done in one day is about 370nm @20knots, and it was a long day!

 

[Robg71]

I can stop off at the brent field for a cuppa and fuel

 

[Keith-i]

The skinflints coming out in me.
Do I need aquadrive cv joints.
15k for a pair can be better spent elsewhere initially...

Take a look at PythonDrive. Almost identical to GKN Aquadrive but a darn sight cheaper. Just fitted one of the smaller versions to our 32 semi-d. The theory/logic behind them makes a lot of sense to me.

 

[taz]

Gaining pace, Rob...........can't wait for the first weld and following build report.

 

[jfm]

I can do skinflint too - born yorkshire
I've never had those drives and never missed them. Sure they might do some very marginal nice things but I do not see much bang for buck at 15 grand. Skip them and better spend the money on buffalo scrotum leather for the saloon chairs, would be my vote.

 

[Robg71]

I shall load up the Holland & Holland,
Now then, how many baw bags do we need

The yard said they were an excuse for a bad engine install "get out of jail free card"
Unless they were needed to drop down the angle of engines in tricky installs.

 

[jfm]

The yard said they were an excuse for a bad engine install "get out of jail free card"
Unless they were needed to drop down the angle of engines in tricky installs.

I like the sound of your yard. Feels like they are proper shipwrights and know what they're talking about. Well done finding them!

 

[ARE]

<As regards gensets, Rob I think you are worrying too much about having too large a genset and running it at 60% load. In my book, you shouldn't worry about that. I'm more interested in not having too small a power output for the peak loads i might want to apply for say 10% of the time. What's the worst that can happen with a too-big genset? Slightly glazed bores at 5-10,000 hours? That's 10++ years away, and you can just pull the whole diesel engine out through the engine room door and buy a new one for 4 grand, job done. Get the Onan 17.5kva single phase. Has a 2.2 litre Kubota engine, soundproof box, all electronic control, accepts autostart, lovely 1500rpm, delivers 65 amps @230v 50Hz easily, dead easy to service (everything is at the front), best in class. >

Without knowing the whole boats loading this is very difficult to answer, but I would prefer to see the generator loaded to 80-90% of max and peak loads picked up with the Victron. I am only guessing here, but I would of thought 11-13kW genset plus 5kW Victron would meet Rob's requirments, unless zero speed stabilizers are on the options list.

I like the hybrid type set up with Generator, inverter, battery bank and auto start functions. Let the inverter pick up the light loads on the battery bank and use the generator for large loads while also recharging the battery bank, with a auto start back up if the battery bank drop's below the recharge set point.

Rob, because your boat is steel hulled, have you though about a keel cooled generator? with a dry exhaust? no sea water pumps to leak or heat exchangers to clean out, plus you can add a large dry silencer to keep the exhaust noise to a minimum.

Anthony

 

[Robg71]

Hi Anthony
Im all ears. keel cooling at work is basically the intercooler bolted to the outside of the hull. is this drag inducing?? or is it possible to do keel cooling through the hull. letting the steel transfer heat through the hull. are these quieter, louder or similar. I had not thought about either to be honest. I assumed it was a yacht thing or displacement type hull, but please tell me more. How efficient are they in warmer waters. (I suppose thats a bit of 'how longs a piece of string', just make em bigger....

with the stabs, we are attempting to make it as simple as possible to fit them retrospectively, if that means the gen set is not big enough, then will deal with that issue then. but, if its possible to account for that now, in the cooling and exhaust, then that is the route i would go by.