One geny or two?

[TonyR123]

Ignoring the cost (for now) would you spec 1x 20kw generator or 2x 10kw generators? Am really thinking of having 2. One reason is for redundancy (so if 1 fails I can use the other). Secondly most of the time I doubt I need 20kw. I don’t tend to use air con during the day when the gyro is on. So 10kw would usually be enough. If 20kw needed then the 2nd would auto start. Thirdly (and I guess somewhat irrelevant) it would be cheaper in fuel.

anyone used ‘whisperpower’ genys? Tempted to go for 2 of these instead of say 2 onan genys.

 

[westernman]

Ignoring the cost (for now) would you spec 1x 20kw generator or 2x 10kw generators? Am really thinking of having 2. One reason is for redundancy (so if 1 fails I can use the other). Secondly most of the time I doubt I need 20kw. I don’t tend to use air con during the day when the gyro is on. So 10kw would usually be enough. If 20kw needed then the 2nd would auto start. Thirdly (and I guess somewhat irrelevant) it would be cheaper in fuel.

anyone used ‘whisperpower’ genys? Tempted to go for 2 of these instead of say 2 onan genys.

How big a cruise ship do you have?

My villa's electricity supply is limited to 6kw. I have big air conditioning units in 4 rooms (used for heating in winter), a huge American fridge.freezer another full sized freezer in the garage, all the usual multiple computers, tablets, TVs and lap top computers as well as the car which is recharging as well. Summer temperatures are 40C or more. The air conditioning is dimensioned to cope with that.

I have never tripped out the 6kw limit.

I would have thought for a normal sized mobo 50ft or so which is not well insulated, with two cabins below, 4kw would be enough if you use gas for cooking.
If you use electricity for cooking, then may be 6kw - or accept you can't have the air-conditioning on full at the same time as using all four hobs and the cooker, the oven and the kettle.

A generator is efficient at 75% load or more. And seriously inefficient below 30% load.

 

[TonyR123]

Well they reckon 17.5kw geny to safely run air con, seakeeper 9, fridge, etc. I would expect the 2nd geny to rarely come on and would be there for redundancy.

surely your house must be more than 6kw? Just charging the electric car is 7.2kw. Oven on top another 7kw.

 

[Bouba]

My 6kw Onan on my 30 footer cuts out when I have two heaters on and then switch on the kettle ....it’s not a problem but 4 on a fifty footer is underpowered, in my opinion.
2 x 10 is good for a few reasons...ease of getting them in and out...weight distribution and economy. I would go for one big one if I only had one space available to put it...and, importantly if the bigger genny has better noise insulation than the two small ones
Ps...check that servicing two smaller ones is cheaper or more expensive

 

[TonyR123]

Think I will go for 2x 9.5kw onan genys (once I have pricing). The whisper power, while slightly quieter, run at higher rpm so shorter service intervals.

I expect JFM will have a few genys on the San Lorenzo!

 

[westernman]

Well they reckon 17.5kw geny to safely run air con, seakeeper 9, fridge, etc. I would expect the 2nd geny to rarely come on and would be there for redundancy.

surely your house must be more than 6kw? Just charging the electric car is 7.2kw. Oven on top another 7kw.

Yes sure. The house is 6kw. The car is a granny charger at 1.8kw.

 

[westernman]

Yes sure. The house is 6kw. The car is a granny charger at 1.8kw.

Just checked. The house is limited to 6kVA.

 

[jfm]

If you have two, you have to decide whether they will be phase synched, and almost certainly they won't be. In which case, you will need a bunch of VSRs to stop them being linked, and you will need to divide your 230v loads into Bus A and Bus B, which isn't easy when single appliances will be using a large % of the 10Kva form each machine. You avoid all that hassle/cost with one 20kw.

I'm a lover of 2 machines, each enough to run the whole boat, and I have no problem running one at 30% load for a big % of its life, despite the contrary views of others on that topic. Who cares about bore glaze and such like. But in a small installation like you're describing I would fit one 20kw to run everything, for switching/synching simplicity, and a 6kw as back up if you really want redundancy.

The whispergen machines, being inverter type, might well have built in plug and play phase synching, which overcomes the downsides in my first para above. But because they are inverter they adjust their rpm to demand, and personally I would hate that so would never buy one as my main machine. If you're happy to live with variable RPM, then they are very nice machines. I would get the onan/Kohler that runs solidly at 1500rpm only, just because of the nicer noise.

 

[Portofino]

Split the outputs .

Smallest one to run the gyro + a charger when at anchor + a few dedicated sockets ( low power chargers ) maybe one kettle socket dedicated in the galley .
Assuming fridges are 24 V on batts ….which are being topped up with number 1s charger as well .

Another bigger one number 2 to run the whole boat inc A/con + another second charger(s) , galley full appliances .But not the gyro .

So anchoring off in daytime frolicking about run No 1 , smallest to do the gyro , charge batts + i pads etc + if wanted have a brew .

As night falls assuming staying there turn on No 2 to pick up the Aircon to chill the cabins , galley ,and if necessary another charger to another bank .
Of it’s dead calm and the gyro is redundant switch No 1 off , keeping No 1 running .

If it’s choppy while cruising switch on No 1 only ( leave it’s charger off as motors alternators are running ) so the gyro works + I pad chargers + if necessary as said a brew depending on season .

Keep them separately wired so it’s only possible to power say the gyro with either no 1 or No 2 but not both simultaneously sos avoid all the syncing malarkey and extra kit and brain power to operate said kit JFM refers to ^ .

If you are time short your guests will never realise one’s knackered if it goes down .The show will go on .You might seek a marina or open windows if no2 the AC is inoperable.

 

[TonyR123]

have to admit I havent thought about syncing them. as the whisper power would be synced then just assumed the onan would as well. I have since discounted the whisper genys due to the variable/higher RPM.

So guess it is one geny to run everything or 2 genys with some loads split. seakeeper is max 3kw on start up (2kw once up and running) so that and everything else on one with the air con would have its own separate geny. Splitting loads might be too much hassle/costly - will find out.

 

[jfm]

If you have decided you don't want variable rpm (good choice, imho), then take a quick look at Kohler because they now offer plug play synching on many of their models, though I'm not sure whether they do that down to 10kva size. They offer it I think from 12kva upwards but I'm not 100% sure - you need what they call Decision-Maker 3500 Paralleling Controller. Onan don't offer this, the last time I looked, though in other respects they are great machines.

I'm always hesitant to suggest which s better out of Onan or Kohler, because they both use different home-made or bought-in engines, depending on the generator model you're looking at. The bought in engines often come from Kubota, Yanmar and sometimes John Deere. At 23-28KVA, Onan use the very nice Kubota 2 litre engine, and at 45-55kva Kohler is better (imho) becuase it uses the even nicer John Deere 4.5 litre engine.

I disagree pretty much every line of Portofino's post #9 above. Too tedious to explain point-by-point, but no-one in their right mind would set up a twin-genset boat like that.

 

[TonyR123]

they werent too keen to install 2x 9.5kw onans, so back to one 17kw onan geny. thats the last of the decisions on the princess v55. build starts in Jan!

 

[jfm]

Didn't realise this was a new build v55. No way would they have ever agreed 2x gensets with all the wiring architecture that needs!

The Onan 17.5 is a great reliable machine anyway - has the excellent Kubota 2 litre engine. Many of them on here - I have had 2 of that model, and 6 of that base engine, and they never missed a beat.

 

[jrudge]

My boat is all electric and the gen runs 24/7 when off the dock. Running it continually for 4-5 days is normal

I would spec 2 if able , but I would also as per the above make sure it can run the whole boat either by being clever or syncing them.

the power you can use on a is surprising. 2 x large ac compressors / gyro / battery chargers as a base load and then add in cooking - microwave / 4 ring hob/ kettle / toaster 10 kWh won’t be enough.

I have stalled my gen due to overload.

so 10/10 I would say no - not enough - but some form of backup on an all electric boat I would say is worthwhile.

to be frank if we had no gyro and ac we would return to the marina.

 

[Hurricane]

The Onan 17.5 is a great reliable machine anyway - has the excellent Kubota 2 litre engine. Many of them on here - I have had 2 of that model, and 6 of that base engine, and they never missed a beat.

Yep that Onan is the one we have - never (yet!!) put a foot wrong.
Same is fitted to a friends Phantom 48 so even working on a smaller boat.

 

[TonyR123]

they would do 2x whisper power, but not 2x onan.

 

[Portofino]

they would do 2x whisper power, but not 2x onan.

Are wisperpower and onan the only company’s who will tolerate Prinys invoice payment policy ?

Wonder how long they squeeze there suppliers 90; , or 120 days ?

Thats the only thing I can think of for the very narrow choices.

 

[Portofino]

My boat is all electric and the gen runs 24/7 when off the dock. Running it continually for 4-5 days is normal

I would spec 2 if able , but I would also as per the above make sure it can run the whole boat either by being clever or syncing them.

the power you can use on a is surprising. 2 x large ac compressors / gyro / battery chargers as a base load and then add in cooking - microwave / 4 ring hob/ kettle / toaster 10 kWh won’t be enough.

I have stalled my gen due to overload.

so 10/10 I would say no - not enough - but some form of backup on an all electric boat I would say is worthwhile.

to be frank if we had no gyro and ac we would return to the marina.

Agree .
The same logic of ending up with two engines ( generally) in mobo .It’s called redundancy.

The more sophisticated, bigger , complex , boat and unable to get a berth in August touring the more redundancy will be be a godsend .

Even if you were to find a pontoon it might not necessarily for a 60 ftr have 64 A shore power or a fully functioning 32 A if all and sundry are hammering the AC on the shore power with there genys off while your only one is knackered .Or they have ran out of adaptors etc. etc .

Nice where space permits to have a back up .

If you wanna be really clever belt n braces for AC load ( which brings in other stuff while low ) get or have a look at Frigomar s brushless DC inverter compressors with draw the lowest amps = even smaller genys or more headroom for the other stuff .

But it sounds like Princess are pretty rigid with the OPs choice said anyhow .Pity really!

 

[TonyR123]

Are wisperpower and onan the only company’s who will tolerate Prinys invoice payment policy ?

Wonder how long they squeeze there suppliers 90; , or 120 days ?

Thats the only thing I can think of for the very narrow choices.

I would expect they only offered onan generators but then offered whisperpower due to supply issues due to lock downs. TBH for a generator (like engines) I wouldnt see why a manufacturer would have multiple choices. Generally you have one or two power options for engines and I guess same for a generator. Navigation you only get offered one option (raymarine, garmin, etc) except for the screen sizes and quantity. Too many options for smaller boats (say <£3m) would surely make the boats less profitable.

 

[Portofino]

I would expect they only offered onan generators but then offered whisperpower due to supply issues due to lock downs. TBH for a generator (like engines) I wouldnt see why a manufacturer would have multiple choices. Generally you have one or two power options for engines and I guess same for a generator. Navigation you only get offered one option (raymarine, garmin, etc) except for the screen sizes and quantity. Too many options for smaller boats (say <£3m) would surely make the boats less profitable.

Just adjust the price menu .Let the punter make the decisions.
If the manufacturers want to influence then artificially add a greater margin to deter them away .
eg geny brand X costs 70% less than Y , both kubota identical powered both within a 1 Kvh similar size .
No surprises 80 % of punters tick X s box .But my point is at least there’s real choice .

I mean as you probably know in the car world “ speccing “ is almost full time job these days particularly with the higher end German marques ,They seem to have the line management to deal with the infinite varieties.Even the humble Fiat 500 can be had in 1/2 a million flavours spewing out hundreds if not 1000 s a day ?

A sloooooow 3-5 month build of a boat creeping along in a boat factory spending days weeks at the same station within the factory can’t be hard for the guys to fit brand Y or Z instead of X .It’s not like JUT on a car plant wherby the fitter has 42 seconds to fit a ICE , before the things moves further down the line .
A boat hull fresh out of the plug is stood for more like 42 days before the topsides mould is attached .Plenty of time to fit other brands of kit .Be them genys , chargers , toilets , down light s etc ,etc
Not talking rejigging bulkheads just cherry picking on a menu .

I mean 1979 the debut yr 4 engines to choose from .

Did you have a power plant choice btw ?

I mean the Fairline infamously named “GT 62 “ …….came only at launch with a slug of engine barley making 31 knots fresh at WOT, Other 60-64 ftrs are near or just over 40 knots and sit all day at 35 knots mid season .

Sunseeker were pretty good take a Porto 53 it could be had in 3 flavours .D12 715 , MAN 800 s both straight shafts and even a Arnesons version ( titled Pred 55 ) with iirc 800 or over a 1000 Hp MAN s .So two drive systems and 4 main engines .
As said plenty of time while the hull is snail pacing through the factory fir the guys to dive into which ever model the punter has picked ,
Sunseeker made good profits remember offering variations .

Ferretti will paint your new boat any colour btw you just give them the RAL number .If it’s one off they just add on € 10 K ….as I said widen there margin over the standard palate .