Hydraulic Motor In Water

Discussion in 'Hybrid' started by Mark Emaus, Aug 23, 2010.

  1. Mark Emaus
    Joined: Jan 2009
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    Location: Georgia

    Mark Emaus Junior Member

    We will keep the shaft tube dry and that should help with the seals. We are leaning now, on having the casing wet. The biggest problem with this is the unit is being designed for shallow water application and will take on mud. What we are thinking now is to have a drain plug on the casing as to wash out any and all mud that may pack between the casing and the motor.

    Someone asked what is driving the motor and we are using a 65 hp air-cooled engine that is driving the Hyd. pump. Ours is producing 45 gpm as to run the hyd. motor.
  2. Wolfhart
    Joined: Jan 2012
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    Location: Bradenton, FL

    Wolfhart New Member

    A salt water hydraulic motor may the solution

    I invented and developed a first genuine water hydraulic motor. I am just starting the production at http://www.wolfhartindustries.com/
    Cooperation would be most appreciated to fit such motor to a boot.
  3. Wolfhart
    Joined: Jan 2012
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    Location: Bradenton, FL

    Wolfhart New Member

  4. johneck
    Joined: Nov 2011
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    Location: New England

    johneck Senior Member

    How about filling the whole thing with oil? This is something that is done for many submerged systems to protect them from seawater. You can perhaps fill to above the nominal waterline to provide a slight positive pressure to insure water does not get in.
  5. tugboat

    tugboat Previous Member

  6. tugboat

    tugboat Previous Member

    char- lynn motors will work fine--this is the set- up i may use for the tug-- at 90% efficiency- a 100 hp diesel coupled to a large pump i think 2.2 cu in displ. this in turn is run through a flow divider to two char-lynn motors of 6.2 cu in displ. at 720 rpms 2000 psi and about 20 gpm per motor- this gives 31 hp ea at 720 rpms and pushes two 22 x 19 props...the flow then returns to a tank -large reservoir....after it goes through two spool valves... you dont need to worry too much in my op. about submersing the motor they are heavily built to withstand the elemtents and might actually help cool the engine... ive seen this done before and wonder why its not done more often because those who have done it says it works great! with this setup you can run twins off one diesel- have instant repsonse and hight torque great forn a tug--the engines char-lynn makes are cont duty btw! also one advantage of this is you can eliminate stuffing box costs. since you would simply mount the engines (if inboards) inside the hull to a pipe which acts as a seal in the same way almost as a outdrive unit...it has many advantages! its cheap - and you dont need transmissions...
  7. tugboat

    tugboat Previous Member

  8. att2tude
    Joined: May 2010
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    Location: Cairns Australia

    att2tude Junior Member

    hydraulic motors

    I salvaged a 40ft catamaran that had one hull completely flooded and the other partially flooded for around 4 weeks. During this time she sat on a beach which ground away her entire port hull. Her main engine was on the bridgedeck(above the flooding) and this powed two hydraulic motors, one in each hull. We airbagged her off the beach and started the diesel and motored her around to be hauled. The hydraulic motors , although they had barnicles on them , operated just fine
  9. michael pierzga
    Joined: Dec 2008
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    Location: spain

    michael pierzga Senior Member

    Ive been using underwater hydraulic motors for years on Bow thrusters. The problem is blown seals.... normally monofilement fishing line.

    Blown seal...oil in the water...haulout and fix. Expensive
  10. brian eiland
    Joined: Jun 2002
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    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    I'll have to have a closer look at your invention.

    Years ago I ran into this hydraulic motor that I thought had great possiblities. The gentleman even built a number of bow thrusters built with this motor design, but he could never get enough capital to carry thru with the whole project.

    There may even be some technologies here that could cross over to your applications? I have more details if you are interested?

    I was just about getting ready to 'overhaul' my website, and this particular section for sure.....more emphasis on chain-drive legs. I was going to take the hydraulic material off of my site and give it its own subject thread, along with some of the additional info I had on it.
  11. brian eiland
    Joined: Jun 2002
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    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

  12. CatBuilder

    CatBuilder Previous Member

    How much does one of those Char-Lynn hydraulic motors weigh?

    I can't seem to find the "2000 series" mentioned in this thread online.

    Can anyone direct me to the specs?

    I am thinking (as a possible alternative to gasoline/petrol outboards and generator, which is the current plan)

    *Single or double diesels with hydraulic pump fitted only
    *Twin hydraulic motor driven legs, hydraulically retractable
    *Hydraulic generator head
    *If feasible, possible hydraulic windlass and winches.
  13. tugboat

    tugboat Previous Member

    31 hp @ 720 rpms!

    there are less powerful ones- high torque low rpms...see below
    12 hp @ 582 rpms
  14. CatBuilder

    CatBuilder Previous Member

    These things weigh 23lbs?!?!?! :eek:

    This whole concept just got a whole lot more interesting! :D

    How big of a reservoir would you say you would need with the proposed tug setup (which sounds identical to the setup that I'd need on my catamaran)? How many liters or gallons or reservoir?

    Seems to me that other than the seal, you could dunk this whole motor into epoxy to protect it from the salt water.

  15. tugboat

    tugboat Previous Member

    YEAH-actually thats a great idea! its sealed anyway-but epoxy would seal it even better..other than the connectors- it would be impervous to any corrosions... but even the connectors could be gooped up with epoxy--isnt it wondeful stuff?!
    yes the oil reservoir is the big cost factor--the oil needs to cool- so they use reservoirs..large ones--with the el-cheapo oil for twin 12 hp you need about 60-80 gallons to be sure nothing will overheat..thats about 1000.00 but its still cheaper than twin engines + upkeeps etc...(if there ever is a shortage of oil you'd also have a 80 gallon reserve on your boat!)
    your cat shouldn't require more hp and speed than those 12 ihp gerotor motors..there are others with less torque and more speed that might work even better for you... they could be installed easily too, just like in an I/O with a seal through hull.
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