Quick v Seakeeper

Nick_H said:
That's interesting Mike. Whilst I agree that the gyro does little at planing speeds, ours is still very effective at all displacement speeds, to the point that we'll happily cook and serve a meal whilst underway at 8-9 kts. IIRC you have a SK9 on a 35T boat? We have SK8 on a 26T boat, which is obviously more turning moment per tonne of boat weight, so maybe that's what makes the difference.

I can't say I really miss the stabilisation much at planing speeds, as it's not the lean of the boat per se that bothers me, it's the violent swinging from one side to the other in a beam sea at rest or disp speed. We don't go out in rough sea though, and of course I've not lived with a fin stabilised boat to know what i'm missing.

edit: on the bearing failure point, i'm in no rush to defend Seakeeper as I thought they could have contributed more to my repair than they did, but I do seem to be an isolated case. I couldn't find any other internet traffic about SK bearing failures, despite them having 5,000 units in the field, some now over 10 years old. They didn't make any attempt to keep me quiet on the issue either, so there's no reason to think that lots have failed but SK have kept a lid on it.
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We are fine on the plane, it is only at very slow & Zero speeds we need a gyro. Nick can be on the boat for hours with no problem, but slow down & bob about for ten minutes & she goes green. Abs 47 is approx 12000kg, SK5 is good for 20000kg so fingers crossed !
 
rubberduck said:
We are fine on the plane, it is only at very slow & Zero speeds we need a gyro. Nick can be on the boat for hours with no problem, but slow down & bob about for ten minutes & she goes green. Abs 47 is approx 12000kg, SK5 is good for 20000kg so fingers crossed !
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Ah OK. Then the SK5 is oversized for the Abs47 which means its probably going to perform better than the SK9 in my boat. How about asking SK or Absolute if they have any previous experience of fitting the SK5 in the Abs47 or a similar boat? What you really want is a sea trial to convince yourself that the SK5 is going to do what you think its going to do. Might be worth contacting SK to ask if they can help. PM me if you want contact details for the guy I was talking to at SK
 
How about this, the smallest Seakeeper is the 3, it can run off a 12v battery. I believe that, like Quick, you can have multiple Seakeeper installations. So two or three Seakeeper 3 each with its own battery and you have a silent gyro. So it might be possible without a generator
 
Deleted User said:
Ah OK. Then the SK5 is oversized for the Abs47 which means its probably going to perform better than the SK9 in my boat. How about asking SK or Absolute if they have any previous experience of fitting the SK5 in the Abs47 or a similar boat? What you really want is a sea trial to convince yourself that the SK5 is going to do what you think its going to do. Might be worth contacting SK to ask if they can help. PM me if you want contact details for the guy I was talking to at SK
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It has apparently been fitted of the likes of Princess 48 with great success, will hopefully be on the south coast early in Jan for a trial.
 
Bouba said:
How about this, the smallest Seakeeper is the 3, it can run off a 12v battery. I believe that, like Quick, you can have multiple Seakeeper installations. So two or three Seakeeper 3 each with its own battery and you have a silent gyro. So it might be possible without a generator
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instead of placing multiple SK3's (@24V DC) , you can run one (or two) SK5 also from battery's via a decent invertor,
in some cases I agree that it makes sense to place multiple smaller units instead of one big, related to space restrictions, not 230V availability.

you may be aware that we run CMC electric stabs at anker for several hours from the batt's via 2 x Victron 5Kw invertors.

sometimes here on the forum is the misconception that a invertor brings a sacrifice in efficiency or reliability ;
the Victron units have a efficiency around 95%,
and in the 5 seasons running Victron invertors on BA we've never had a unit failing
 
BartW said:
instead of placing multiple SK3's (@24V DC) , you can run one (or two) SK5 also from battery's via a decent invertor,
in some cases I agree that it makes sense to place multiple smaller units instead of one big, related to space restrictions, not 230V availability.

you may be aware that we run CMC electric stabs at anker for several hours from the batt's via 2 x Victron 5Kw invertors.

sometimes here on the forum is the misconception that a invertor brings a sacrifice in efficiency or reliability ;
the Victron units have a efficiency around 95%,
and in the 5 seasons running Victron invertors on BA we've never had a unit failing
Click to expand...

I've sketched the below for next boat, 2 x 24V 200A NMC lithium batteries, which are good for 2000 cycles at 80% DOD.

Based on an estimated 1150W consumption for the AC motor (at anchor) this setup should be good for circa 4 hours, which covers my UK usage.

I've stuck a lot of monitoring stuff on there to give myself a gadget fix.

Gyro Power System Diagram (Victron HE batteries).png
 
Anders_P42 said:
I've sketched the below for next boat, 2 x 24V 200A NMC lithium batteries, which are good for 2000 cycles at 80% DOD.

Based on an estimated 1150W consumption for the AC motor (at anchor) this setup should be good for circa 4 hours, which covers my UK usage.

I've stuck a lot of monitoring stuff on there to give myself a gadget fix.

View attachment 68030
Click to expand...

Nice plan !
I've send it to a collegue here in the company who has designed quite a few Li ion installs for OB Vans, (building one here right now ) if he has additional advice I'll let you know,

after a conversation at Mets with a experienced Victron product specialist, the conclusion was that conversion to Li-ion batt's has no benefit for my old fashion installation, and heavy boat.
a weight reduction of approx 250kg on a 55Ton boat doesn't justify for the much bigger investment.
But on a newer and much lighter boat, ofcause the reasoning is different !

here in this thread I explained all the features we have in our setup
might give you inspiration for the new boat :encouragement:

don't know your cruising area, but this is typically for the med,
fe sometimes on a berth with lo amps shore connection, ... etc.

http://www.ybw.com/forums/showthrea...am-of-Blue-Angel-(Canados-70s)&highlight=230V
 
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BartW said:
Nice plan !
I've send it to a collegue here in the company who has designed quite a few Li ion installs for OB Vans, (building one here right now ) if he has additional advice I'll let you know,

after a conversation at Mets with a experienced Victron product specialist, the conclusion was that conversion to Li-ion batt's has no benefit for my old fashion installation, and heavy boat.
a weight reduction of approx 250kg on a 55Ton boat doesn't justify for the much bigger investment.
But on a newer and much lighter boat, ofcause the reasoning is different !

here in this thread I explained all the features we have in our setup
might give you inspiration for the new boat :encouragement:

don't know your cruising area, but this is typically for the med,
fe sometimes on a berth with lo amps shore connection, ... etc.

http://www.ybw.com/forums/showthrea...am-of-Blue-Angel-(Canados-70s)&highlight=230V
Click to expand...

Thanks, I'd appreciate his feedback. I specced the Quattro 24/5000 because the 3000 de-rates to 1700W at 65C (warm engine room) and the 5000 can charge at 120A which the two Lithiums will fully absorb.

I designed the same setup using 12V Trojan batteries (4 x 150Ah) and it would only last 3 hours. And the weight goes up from 56KG for Lithium to 156KG for lead acid. Plus there's hassle having custom battery box made for lead acid.

It looks like Victron batteries are a rebadged version of these:

https://www.mgenergysystems.eu/products/mg-lithium-ion-battery-module/

I haven't found online pricing for the MG batteries, I wonder how pricing compares.

Nice set up you have there.
 
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