Re: Trolling Motors

[protek@shreve.net]

   I too am concerned about safety.  For the most part I do not jump into
one of these discussions unless there is something pertaining to safety
being tossed around.  I have an estimated 196 pounds of thrust on my boat,
not the 28 or 30 that is being discussed here.  Believe me, I have thought
about the hole in the hull scenerio many times.  And if this ever happened
there are three things I would do in the below listed order:

(1) Blow all tanks

(2) Drop both weights

(3) Point the nose up and apply max power (6.6HP)

    The concept of ballast tanks and safety can not be separated.  They ARE
your main line of defense against a problem as discussed.  Common sense
limits the depth you want to go based on the amount of pressure available
and the volume of air that can be delivered.  I can generate well over 1000
pounds of lift from my tanks.  This of course is derated as you go deeper.

    Also concerning safety is the statement that I made earlier that if you
are relying on motor propulsion as your primary emergency means of getting
to the surface you are making a major safety mistake.  Do I think you are
safer with failure proof shaft seals?  The answer is yes.  But I will tell
you that my 6.7Hp is not my security blanket.  My tanks are.

    Lets say that you could direct your trolling motor such that the thrust
is vectored totally upward.  And that is going to be very difficult with
one motor.  The upward thrust with a 30 pound motor would be the same as a
ballast tank filled with less than 1/2 cubic foot of air.

    I may write Richard Hess about this.  He has a supply of clubs.  :-)


Gary Boucher




>I know this is a "dead horse" by now but the concern over the shaft seals
is a
>safety concern.
>
>One of the techniques the US Navy practicies for casualty drills (holed hull,
>you just sprung a leak) is to go to full power and point the sub upward. The
>hope is that you can make it to the surface before you take on so much water
>that you never will make it. As a side benefit of heading for shallower
water,
>the water pressure is less thus there is less water being forced into your
>hull.
>
>The option of powering to the surface requires a good shaft seal on your
>trolling motors because it is your motors that provide the motive force. They
>conk out you don't go.
>
>Of course there are other techniques in case of casulty. Like blowing main
>ballast tanks or dropping ballast. These however have their own problems.
Like
>blowing main ballast is dependant on sea pressure and volume of blow air
>available. Will you get enough positive bouyancy fast enough to make it to
the
>surface. Dropping ballast is mechanical and could jam. The motoring to the
>surface approach gives you three options to  make it to the surface
instead of
>just two.  
> 
>Even in a wet sub the motoring to the surface techique is important. If you
>get a leak  at 120 feet. How fast can you bail? You might be 150+ before you
>get clear of the sub.
>
>Regards,
>Ray