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10-12-2015, 07:14 AM
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#1
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Guru
City: Galveston, Texas
Vessel Model: 24" El Pescador
Join Date: Nov 2014
Posts: 743
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Generator as "Get Home" power
As an offshoot of the "Single vs Twin" thread:
What does it take to make your generator also serve as a Get-Home engine?
Seems this would be a cost effective way to add the capability but you still have a common shaft/prop.
Assume a larger genset for one.
Hydraulic pump or a belt drive of some sort on the propeller shaft?
If this is your only genset and you increase the size, how do you manage it wrt loading it properly for normal use?
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10-12-2015, 07:45 AM
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#2
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Guru
City: Carefree, Arizona
Vessel Name: sunchaser V
Vessel Model: DeFever 48 (sold)
Join Date: Apr 2008
Posts: 10,179
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Quote:
Originally Posted by ktdtx
As an offshoot of the "Single vs Twin" thread:
What does it take to make your generator also serve as a Get-Home engine?
Seems this would be a cost effective way to add the capability but you still have a common shaft/prop.
Assume a larger genset for one.
Hydraulic pump or a belt drive of some sort on the propeller shaft?
If this is your only genset and you increase the size, how do you manage it wrt loading it properly for normal use?
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Wesmar offers a system with hydraulic drive off genset connecting to either existing shaft or auxiliary get home shaft. Selenes and Northern Marine have a variety of hydraulic setups worth a look.
The best get home setup I've seen is on the Dashew FPB 64s. Boat speed is 7 to 8 knots with main shut down.
I recently noticed a Nordhavn 52 for sale that had 750 hours on the main and 110 hours on the get home.
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10-12-2015, 08:16 AM
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#3
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Guru
Join Date: Oct 2007
Posts: 22,553
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The best combination seems when the boat uses hyd for many purposes.
The main gets a hyd pump large enough to run a hyd cruise generator 4 -6KW (or two) is not a big drain.
The noisemaker is operated during docking with its high RPM running to provide power to the bow or stern thrusters.
Otherwise it too feeds the same hyd power pack as the main would for AC juice.
This gives the flexibility to use either a hyd motor on the shaft , or to power a wing prop with a hyd motor.
The wing prop needs to be for pushing , not for slimness while under sail, so the HYDE is the only feathering units built for this service.
Hyd has a bit more involved when installing , but when overloaded it has no white smoke to escape.
And when desired the bow thruster can be used for more than seconds.
Would be an expensive retrofit for a voyager.
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10-12-2015, 04:04 PM
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#4
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Guru
City: Galveston, Texas
Vessel Model: 24" El Pescador
Join Date: Nov 2014
Posts: 743
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Quote:
Would be an expensive retrofit for a voyager.
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That's why I was focusing on driving the existing shaft/prop. Seems it would be less expensive.
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10-12-2015, 04:12 PM
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#5
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Guru
City: Vermont
Join Date: Jan 2013
Posts: 10,076
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I know a couple of people with hydraulic drives on the main shaft as a backup propulsion system. Power is from a hydraulic pump on the gen set..
__________________
MVTanglewood.com
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10-12-2015, 05:27 PM
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#6
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Guru
City: Windsor
Vessel Name: Keeper IV
Vessel Model: 44 Viking ACMY
Join Date: Nov 2013
Posts: 1,350
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Quote:
Originally Posted by ktdtx
That's why I was focusing on driving the existing shaft/prop. Seems it would be less expensive.
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I suppose as long as you can still turn the main shaft.
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10-12-2015, 05:34 PM
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#7
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Guru
City: Sydney
Vessel Name: Sojourn
Vessel Model: Integrity 386
Join Date: Oct 2011
Posts: 13,293
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Quote:
Originally Posted by sunchaser
...I recently noticed a Nordhaven 52 for sale that had 750 hours on the main and 110 hours on the get home.
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Using the auxiliary for maneuvering/docking (as I think Bay Pelican does) could account for some hours as could "exercise", but it seems disproportionate. What brand is the main?
__________________
BruceK
2005 Integrity 386 "Sojourn"
Sydney Australia
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10-12-2015, 05:36 PM
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#8
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Guru
City: Walnut Grove Ca
Vessel Name: Cary'D Away
Vessel Model: Hatteras 48 LRC
Join Date: Apr 2012
Posts: 887
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Chain Drive with clutch
Quote:
Originally Posted by twistedtree
I know a couple of people with hydraulic drives on the main shaft as a backup propulsion system. Power is from a hydraulic pump on the gen set..
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I worked on a small trawler with a generator driven hydraulic pump, and chain driven main shaft from a hydraulic motor. It had been abandoned at the coupling for whatever reason, the motor and pump had a forward and reverse control at the helm. With a generators constant RPM I could see some issues maneuvering. Everything worked except it was disconnected from the shaft. I was doing survey work that included aligning the engine and propshaft. At time I thought it looked like a good idea. The clutch and chain were a rusty mess, I would guess lack of maintenance is the reason the system was abandoned.
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10-12-2015, 07:12 PM
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#9
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Guru
City: Gulf Shores, Ala.
Vessel Name: Ulysses
Vessel Model: Romsdal 1963
Join Date: May 2013
Posts: 878
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I have the chain driven main shaft arrangement running off of hyd. from Gen. Set. One direction-no speed control from helm. It is a "get close to home" arrangement then ask for an assist.
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10-12-2015, 09:15 PM
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#10
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Guru
City: South FL
Vessel Name: Oliver
Vessel Model: Nordhavn 47 Hull# 12
Join Date: Apr 2013
Posts: 3,607
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Quote:
Originally Posted by BruceK
Using the auxiliary for maneuvering/docking (as I think Bay Pelican does) could account for some hours as could "exercise", but it seems disproportionate. What brand is the main?
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Also they are used for anchoring.
__________________
Thanks, Oliver
M/V Oliver
Nordhavn 47 Hull #12
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10-12-2015, 09:19 PM
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#11
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Wannabe
City: SF Bay Area
Vessel Name: Stillwater
Vessel Model: Kadey-Krogen 54
Join Date: Dec 2014
Posts: 782
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Quote:
Originally Posted by ulysses
I have the chain driven main shaft arrangement running off of hyd. from Gen. Set. One direction-no speed control from helm. It is a "get close to home" arrangement then ask for an assist.
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I'm seriously considering a hydraulic get home at some point. I have two gensets on board a 20kW and an 8kW. I was thinking I could put the hydraulic pump on the 20kW genset.
What size genset do you have and how powerful is your hydraulic motor? What size is your boat and what speed can you make with it?
Thanks
Richard
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10-13-2015, 01:56 AM
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#12
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Guru
City: Gulf Shores, Ala.
Vessel Name: Ulysses
Vessel Model: Romsdal 1963
Join Date: May 2013
Posts: 878
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Richard: The boat is about 52' steel hulled 47 ton. The gen set that can provide the get home is a 20KW. I have yet to have to hook up the chain drive but I would imagine it would make about 3 knots. I will check the next time I am on the boat as to the specs of the Hyd. motor.
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10-13-2015, 03:17 AM
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#13
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Guru
City: Melbourne, FL
Join Date: Dec 2014
Posts: 1,731
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What about the electric saildrive options? MasterVolt and several others offer that option and are quite small footprint. I am curious about the losses compared to hydraulics but my best source was my late father but he's gone now. I know lots of larger ships do generators to electric drives (and locomotives too). Why not an electric get home engine? With a folding prop, it should be minimal maintenance and drag.
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10-13-2015, 07:20 AM
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#14
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Guru
City: Galveston, Texas
Vessel Model: 24" El Pescador
Join Date: Nov 2014
Posts: 743
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What about GenSet size. If you size your GenSet for get home power and the main use is to provide electricity for the boat are there any long term problems with chronically underloading the generator engine?
Any way to manage this?
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10-13-2015, 07:30 AM
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#15
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Guru
City: Gulf Shores, Ala.
Vessel Name: Ulysses
Vessel Model: Romsdal 1963
Join Date: May 2013
Posts: 878
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Ktdtx: I have a 5 KW gen set that I typically use a couple hours a day to run the batt chargers, refrig. and normal lighting requirements. My 20 KW I run to handle those same loads and Air Conditioning when necessary. The 20 KW is the get home engine. Therefore, I do not chronically under-load the 20 KW.
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10-13-2015, 08:49 AM
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#16
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Wannabe
City: SF Bay Area
Vessel Name: Stillwater
Vessel Model: Kadey-Krogen 54
Join Date: Dec 2014
Posts: 782
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Quote:
Originally Posted by ulysses
Richard: The boat is about 52' steel hulled 47 ton. The gen set that can provide the get home is a 20KW. I have yet to have to hook up the chain drive but I would imagine it would make about 3 knots. I will check the next time I am on the boat as to the specs of the Hyd. motor.
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Sounds familiar. Stillwater is 54' and about 35 tons. I have two NL gensets - a 20kW and 8kW. So why haven't you tried the get home yet? Was it installed by a PO?
Richard
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10-13-2015, 08:51 AM
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#17
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Wannabe
City: SF Bay Area
Vessel Name: Stillwater
Vessel Model: Kadey-Krogen 54
Join Date: Dec 2014
Posts: 782
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Quote:
Originally Posted by stubones99
What about the electric saildrive options? MasterVolt and several others offer that option and are quite small footprint. I am curious about the losses compared to hydraulics but my best source was my late father but he's gone now. I know lots of larger ships do generators to electric drives (and locomotives too). Why not an electric get home engine? With a folding prop, it should be minimal maintenance and drag.
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One of my concerns would be duty cycle. If I really need a get home motor it'll be because I'm out of tow range. If I'm half way to Hawaii then I could need to run it for 1000 miles. I'm not sure if want to do that with an electric motor.
Richard
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10-13-2015, 09:23 AM
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#18
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Guru
City: Gulf Shores, Ala.
Vessel Name: Ulysses
Vessel Model: Romsdal 1963
Join Date: May 2013
Posts: 878
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Richard: Well, I guess that I misstated a comment above. I have hooked up the chain and made sure all worked as designed. I only ran it a minute or so at dock. I meant to say I have never HAD to run it due to loss of main engine. I am not sure as to which PO installed it but it has been there awhile. With a 52 year old boat it is sometimes difficult to get the history of what all has been done and what might have been original, I am pretty sure the get home is not original. I might ask Delfin if he had one on his Romsdal.
As to hooking it up: I would think it would be somewhat of a challenge in heavy seas of course I find a lot of things more challenging these days.
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10-13-2015, 09:27 AM
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#19
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Wannabe
City: SF Bay Area
Vessel Name: Stillwater
Vessel Model: Kadey-Krogen 54
Join Date: Dec 2014
Posts: 782
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Quote:
Originally Posted by ulysses
Richard: Well, I guess that I misstated a comment above. I have hooked up the chain and made sure all worked as designed. I only ran it a minute or so at dock. I meant to say I have never HAD to run it due to loss of main engine. I am not sure as to which PO installed it but it has been there awhile. With a 52 year old boat it is sometimes difficult to get the history of what all has been done and what might have been original, I am pretty sure the get home is not original. I might ask Delfin if he had one on his Romsdal.
As to hooking it up: I would think it would be somewhat of a challenge in heavy seas of course I find a lot of things more challenging these days.
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Ah ok. That makes sense. How to hook up the drive is one of the areas of interest. Ideally it would be quick and easy.
Thanks
Richard
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10-13-2015, 10:19 AM
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#20
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Guru
Join Date: Oct 2007
Posts: 22,553
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"I suppose as long as you can still turn the main shaft."
And the transmission does not mind freewheeling with a load on its thrust bearing.
An extra tranny oiling setup might be required.
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