Re: Trolling Motors

[Albert Long <subview@mediaone.net>]

I think that a lot you think that the trolling motors were being discussed as
"main" propulsion, I just want a bow thruster. I have a 4 1/2 horse main
propulsion motor.
I also feel that propulsion cannot replace the simplicity and power of blowing the
mains
as a means of attaining the surface.

protek@shreve.net wrote:

>    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