[PSUBS-MAILIST] actuators

Thu Jul 5 09:49:34 EDT 2018

Hank, it has been awhile since I played with the Lenco trim actuators but
to the best of my memory, it was uniformly slower both when extending and
retracting.  If the tear down was as I remember, the DC motor was high
speed with a significant set of reduction gears.  On the motor was a fan
with lots of small blades to cool the motor.  My working hypothesis is that
this fan was designed for air not light oil.  As such, even with the low
viscosity oil I was using, the drag caused by this fan operating in oil
would be dramatically higher than for air.  I think this caused the motor
to consistently spin slower than with oil, this the reduced stroke speed by
extending or extracting.  I never tried this but if this was indeed the
cause of reduced speed and not oil lifting the brushes off, then an easy
fix would be to remove the fan or fan blades.  I think the cooling would be
adequate given the low duty cycle particularly while submerged. With the
fan removed you would have to limit use out of surface to keep from
overheating the motor.

OAS, I enjoyed meeting you and your wife and learned some things that I
will implement on my boat.  I particularly like the your trailer setup for
launch and retrieval.  My new goal is to launch and retrieve by boat like
Hank!  This will entail two trailer mods.  The first is I am going to weld
a 4x4 by 10 extension just aft of my hitch.  Maxi has a boat we use for a
tender so I don't need the dingy and as such don't need a wide platform.
The second modification is that I am going to install two Lenco trim liner
actuators on my "Y" yoke at the stern end of my trailer and run these of
the trailer emergency brake battery.  This will enable me to lock in the
stern of the boat without having to fiddle around in the water with
straps.  After the boat has been cradled and pulled out of the water and
away from ramp, I can then attach straps.  These changes should
dramatically reduce my launch and retrieval time.  I may end up using a
larger trailer 12V battery than what comes with the electric brakes.  I am
also going to permanently attach a kit box on the extension that I can stow
straps, chocks, tire tools, small floor jack plus miscellaneous spare
parts.   Given that my new trailer brakes failed about an hour out of Lake
Tahoe, I am going to look into adding electric brakes to the second axle.

On the negative side this new arrangement will impose a minimum boat ramp
angle that I can launch from.

One of the highlights of the trip for me was the dive we made on Tuesday
together.  I got a kick out of seeing your boat as we descended.  I got one
little video clip from Alec of us at about 100 ft.  Hoping to get more.

Best Regards

Captain Redus

On Thu, Jul 5, 2018 at 6:33 AM, hank pronk via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> Cliff,
> Was the reduced speed of stroke in both directions?
> Hank
>
> On Wednesday, July 4, 2018, 7:29:46 PM MDT, Cliff Redus via
> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
>
> I used small plastic accordion shaped reservoirs, one per actuator.
> Worked ok but oil seemed to make them stroke slower.  I had them place on
> control surfaces for first Islamorada psub convention.  Dives were shallow.
>
> Sent from my iPhone
>
> On Jul 4, 2018, at 3:42 PM, hank pronk via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
> Hi Cliff,
> At Lake Tahoe, you mentioned that you oil compensated your Lecno
> actuator.  Did you use a bladder reservoir?  Did you have any time in the
> water with the actuator under pressure?
> thanks'
> Hank
>
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