Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 03-12-2012, 19:12   #1
cruiser

Join Date: Sep 2007
Location: Tampa to New York
Boat: Morgan 33 OutIsland, Magic and 33' offshore scott design "Cutting Edge"
Posts: 1,594
Hydraulic Drive Ideas

So I have a boat with a running diesel and a junk transmission. I started rebuilding the trans hbw 50 hurth and find out its just not a long lasting reliable unit. I don't want it in my boat. After kicking around adapting a different trans ii come up with the idea why not just mount a hydraulic pump and a generator head to the diesel. Then use a hydraulic motor to drive the propshaft. This opens up the option of using another motor to drive the windlass. The pumps and motors I looked at were all relatively inexpensive, although I can see money going into piping control valves etc... So why not?
__________________

__________________
forsailbyowner is offline   Reply With Quote
Old 03-12-2012, 19:17   #2
Registered User

Join Date: May 2011
Location: Toronto
Boat: Sandpiper 565
Posts: 2,943
Re: Hydraulic Drive Ideas

less efficient? less reliable than the hurth?

(just spritzing; I don't know hydraulic drives)
__________________

__________________
Lake-Effect is offline   Reply With Quote
Old 03-12-2012, 19:28   #3
cruiser

Join Date: Sep 2007
Location: Tampa to New York
Boat: Morgan 33 OutIsland, Magic and 33' offshore scott design "Cutting Edge"
Posts: 1,594
Re: Hydraulic Drive Ideas

[QUOTE=Lake-Effect;1099608]less efficient? less reliable than the hurth?

Dpnt know efficiency of hurth. Hydraulic ad states 95% efficiency.

Hurth is described as 1000 hour transmission at cost of $1000 to rebuild. Pita to remove and reinstall.

Hydraulic drive rated for 1000 rpms continuous duty in industrial or agriculteral setting. Would be very simple to remove and replace. Cost around $300 so carry a spare or two.
__________________
forsailbyowner is offline   Reply With Quote
Old 03-12-2012, 19:40   #4
Senior Cruiser
 
DeepFrz's Avatar

Cruisers Forum Supporter

Join Date: Mar 2006
Location: Winnipeg
Boat: None at this time
Posts: 7,930
Re: Hydraulic Drive Ideas

Gee, I wonder why no one else has thought of this?
__________________
DeepFrz is offline   Reply With Quote
Old 03-12-2012, 20:05   #5
Registered User

Join Date: May 2008
Location: daytona beach florida
Boat: csy 37
Posts: 2,844
Images: 1
Re: Hydraulic Drive Ideas

not too common, but i read about one racer a dozen or more years ago that did that very thing. was a fairly large boat - over 50'. the advantage to the racer was that the heavy engine could be installed in the most advantageous position - directly over the fin keel, and the connection to the hydraulic motor was by flexible hose, rather than a solid shaft.

i've always thought it was a really good idea, but i haven't got the skill or the time or the $$$ to try it...
__________________
onestepcsy37 is offline   Reply With Quote
Old 03-12-2012, 20:22   #6
Mooderator
 
capngeo's Avatar

Cruisers Forum Supporter

Join Date: Jul 2010
Location: Key West & Sarasota
Boat: Cal 28 "Happy Days"
Posts: 4,211
Images: 12
Send a message via Yahoo to capngeo Send a message via Skype™ to capngeo
Re: Hydraulic Drive Ideas

Well.... it has been thought of. I used to skipper a dinner boat that was hydraulic drive; 85' of hydraulic drive. It was done so as to locate the machinery away from the diners. The main propulsion engines were also coupled to gensets which were huge as the galley was all electric. The engine room was directly below the wheelhouse and the galley was between it and the dining room. The hydraulic lines ran aft OUTSIDE THE HULL in order to cool the oil. Also it used vegetable oil in case there was a leak (there were many).

The biggest issues as I recall were corrosion as the components were off the shelf for industrial applications and not marinized.... in spite of an almost full time painter there was a lot of rust. Many bow/stern thrusters on commercial vessels are hydraulic, so I would think marinized parts should be available.
__________________
Any fool with a big enough checkbook can BUY a boat; it takes a SPECIAL type of fool to build his own! -Capngeo
capngeo is offline   Reply With Quote
Old 03-12-2012, 20:37   #7
Registered User

Join Date: May 2011
Location: Toronto
Boat: Sandpiper 565
Posts: 2,943
Re: Hydraulic Drive Ideas

Quote:
Originally Posted by forsailbyowner View Post
Hydraulic ad states 95% efficiency.
This forum post suggests that hydraulic drive efficiency is in the 70's whereas motor to transmission to prop is in the 90's

I have seen hydraulic drives on applications like boat carriers (we have 4 at our club), where the big requirement is drive flexibility (pivoting drive wheels) and other uses (hydraulic lift).

This article suggests that hydraulic marine drive is more robust in variable conditions with lots of shifting. Probably not applicable to the average cruiser.

Quote:
Originally Posted by onestepcsy37
i read about one racer a dozen or more years ago that did that very thing. was a fairly large boat - over 50'. the advantage to the racer was that the heavy engine could be installed in the most advantageous position - directly over the fin keel
This of course is an advantage in boat design.

I'd be much more inclined to use a diesel generator-electric motor arrangement than hydraulic. I think a diesel-electric system is much more maintainable by the average cruiser, and of course will also charge boat batteries.

I don't have the numbers but I believe a diesel-electric system with modest battery capacity (eg 1 hour of motoring) is still more efficient than hydraulic drive, and has the added bonus of battery-only operation for short jaunts like entering/exiting a marina
.
__________________
Lake-Effect is offline   Reply With Quote
Old 03-12-2012, 20:50   #8
Registered User
 
TeddyDiver's Avatar

Join Date: Aug 2010
Location: Arctic Ocean
Boat: Under construction 35' ketch
Posts: 1,828
Images: 2
Re: Hydraulic Drive Ideas

It's doable. Thou a couple of down sides. To get high effiency you need closed circuit hydraulics (higher pressure, costing more) Did a lot research some years ago pondering the same thing..
If you get your hands on reasonbly new Bobcat or another work machine apropriate size you could harvest most parts but they are not too cheap either..
__________________
TeddyDiver is offline   Reply With Quote
Old 03-12-2012, 20:53   #9
Registered User

Join Date: Nov 2011
Location: Montegut LA.
Boat: Now we need to get her to Louisiana !! she's ours
Posts: 3,421
Re: Hydraulic Drive Ideas

Have been on a couple of Hydr propelled boats in the past ! One of which was a school boat for teaching folks marine subjects offshore. had two 671 detroits running hydralic pumps which ran everything aboard from movement to gennys! boat was a poor design for handling at sea, but the hyd drive worked wondefully! boat would turn in its own lenght, go from forward to reverse faster then any tranny boat Ive ever ran!! and makeing a dock in high winds it was a pure pleasure! But the whole boat was a terrible rough water boat, lots of rock and roll!! LOL and lots of sick students LOL Im sure if ya can fix the prop shaft to be fixed in place then a hydralic system should work well !! altho I would go with the biggest pump ya can fit to be able to have the thrust ya need !! Just my 2 cents
__________________
Bob and Connie
bobconnie is offline   Reply With Quote
Old 03-12-2012, 21:04   #10
Senior Cruiser
 
roverhi's Avatar

Cruisers Forum Supporter

Join Date: Aug 2005
Location: Kona, Hawaii, Carlsbad, CA
Boat: 1969 Pearson 35 #108 & 1976 Sabre 28
Posts: 6,006
Send a message via Yahoo to roverhi
Re: Hydraulic Drive Ideas

Hydraulic drives were much more common when diesel was $.50 a gallon. Seemed to drop out of favor as the cost of diesel rose and the inefficiency of the hydraulic drive began to seriously hurt the pocketbook. Also think that hydraulics are high maintenance and a super big mess if a hose blows. Judging by the yellow equipment I've seen on construction sites, hydraulics seem to be leakers even when it's working properly.
__________________
Peter O.
'Ae'a Pearson 35
roverhi is offline   Reply With Quote
Old 03-12-2012, 21:17   #11
cruiser

Join Date: Dec 2011
Location: Key West FL - Burlington VT
Boat: O'day 32 CC Ketch
Posts: 493
Re: Hydraulic Drive Ideas

Putting a hydraulic system is a great idea but it wont be great if you try to do it on any sort of budget. Its not the cheaper route by any means. slapping the same tranny in would be way cheaper. Ever tried to build a kick ass log spliter? Maybe the heavy duty pump and motor only cost a grand or so, but valves, hoses, brackets, custom fab, and new prop will cost you. Depends if you do it like a hack or make it a work of art. A new pump would last a very long time, no need for a spare.
Also most electric boats suck because they lack a diesel genny big enough to run them at full throttle all day.
__________________
RabidRabbit is offline   Reply With Quote
Old 03-12-2012, 21:25   #12
Senior Cruiser
 
DeepFrz's Avatar

Cruisers Forum Supporter

Join Date: Mar 2006
Location: Winnipeg
Boat: None at this time
Posts: 7,930
Re: Hydraulic Drive Ideas

Hydraulic systems on a boat like drives or stabilizers also need cooling systems which add a lot of cost, complexity and weight. Properly installed hydraulic systems wont often leak however each connection is a point of failure. Trying to go cheap with hydraulics will ruin your day.

By the way my comment above was meant as tongue in cheek. If it came across as to sarcastic I apologize.
__________________
DeepFrz is offline   Reply With Quote
Old 03-12-2012, 21:41   #13
Senior Cruiser
 
SkiprJohn's Avatar

Cruisers Forum Supporter

Join Date: May 2006
Location: Kea'au, Big Island, Hawaii
Boat: Cascade, Sloop, 42 - "Casual"
Posts: 14,192
Re: Hydraulic Drive Ideas

My friend installed one in his Juno many years ago. Had a Lister air cooled diesel and ran a pump and motor for his drive. Worked but not very well. He had a devil of a time mating the size of his prop to the drive train.
__________________
John
SkiprJohn is offline   Reply With Quote
Old 03-12-2012, 22:15   #14
Registered User
 
Astral Blue's Avatar

Join Date: Mar 2012
Location: Sacramento, CA
Boat: Bayliner Victoria 2750
Posts: 313
Send a message via Yahoo to Astral Blue
Re: Hydraulic Drive Ideas

Cost is going to be your biggest obstacle. Yes, it can be done. I have experience working with hydraulic drive systems and can without a doubt tell you it will cost far more than $1000. Your Hurth transmission will seem like a bargain compared to the cost you will incur with a properly designed system.

This isn't anywhere close to being as simple as a hydraulic drive system for a bow or stern thruster. Those systems are not designed for continuous use; nor do they have much horsepower. When you need a system rated for continuous use in a power intensive application as you describe, it becomes increasingly complex, hence increasingly costly.

You will need to have a cooling system designed for such an apparatus. This cooling system will need to handle the high pressure flows of most hydraulic systems (unless it is on the low pressure end, which has disadvantages associated with it).

Once this system is designed, purchased/fabricated, installed, and tested...then comes maintenance. That's the fun part of working with hydraulic systems. Every single point of connection will need to be constantly monitored in the initial stages of operation. And in a system like the one you propose, there will be many many many points of connection. The oil needs to be changed on a regular basis...and perhaps more often than on a transmission. There will be several filters that need to be replaced frequently.

The quick and dirty answer is "Yes. It can be done!" But since it is your boat and your project, I would suggest you do a lot of research beforehand. A good starting point is a book titled "Introduction to Fluid Power" by James Johnson. It will give you a good starting point in thinking about the advantages and disadvantages of such a system.
__________________
Ed & Lindsey - Sacramento, CA
1977 Bayliner Victoria "Astral Blue"
MMSI #: 338127697
Astral Blue is offline   Reply With Quote
Old 03-12-2012, 22:23   #15
Registered User
 
TeddyDiver's Avatar

Join Date: Aug 2010
Location: Arctic Ocean
Boat: Under construction 35' ketch
Posts: 1,828
Images: 2
Re: Hydraulic Drive Ideas

Quote:
Originally Posted by Astral Blue View Post
can without a doubt tell you it will cost far more than $1000. Your Hurth transmission will seem like a bargain compared to the cost you will incur with a properly designed system.
Think it's closer to $10000 to invest for a proper setup
__________________

__________________
TeddyDiver is offline   Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 05:34.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.