Dumb electricity question

My post here is based on higher voltages.

Sadly over somewhere between 600v and 800v (nearer the later) burns override all other factors...
Over 1000v is usually not used in boats or smaller ships but larger like aircraft carriers it is typical.

At the higher voltage levels you can receive server 3rd degree burns instantly melting away flesh like a rocket engine might. Line men working in the field are very much in peril to these kind of shocks.

The path of electricity is not predicable in field or shipboard situations... being on deck during a thunderstorm is probably the best way to risk a lightening strike. I suggest you goggle search "lightening marks on skin" the unpredictable paths become obvious.

An interesting trick question involves this... "On a flat disk conductor can a voltage differential exist for an applied potential?" NO but that generally does not take account for but for three cases that are similar.
First a homopolar generator... but that is an applied magnetic field moving across the disk...
Second, for an instantaneous application of a high voltage charge like a lightening strike where the path over (not through the disk) creates a magnetic field creating a voltage differential that varies over the surface of the disk this is partly explained by the third.
Third for a Electret material in contact with the disk where the pattern of electrical potential can be varied over the surface of the disk like a happens with a some types of microphones, radiation detectors, copy machines and importantly bio-electret applications (a cutting edge area of investigation where lots of money will be made in the near future).
This shows the danger of trying to predict the path of electricity the danger is that electricity is influenced by magnetics or the dipoles in an electret material in contact with a conductor.
I think in the case of electrical shock from high voltage the body acts like a electret (storing a charge for a short time in this case) with the skin as the primary conductor this then causes the electric current to flow over the skin based on the variation in the unlaying tissue temporal electret properties... Lichtenberg figures on the body I think are described by this but traditionally it is explained differently paths following capillaries. Who really knows but high voltage is strange.
Lower voltages...
At lower voltages usually associated with electrical shock are more dangerous as to heart and internal problems as current flow thens to pass through rather than around the body disrupting electrical paths on the heart. This is bad because as in the case of a what is called medically a 'bundle block' of the heart which can happen due to induced shock electricity to the heart the electrical paths over it that control its beating can be very hard to restart from fibrillation conditions where the fibrillation stops the heart.

To work on ships with over 1000V Mains Engineers need to get their tickets endorsed specifically for this and if not able to achieve this by onboard training need to do an HV Course. My Ticket at last renewal came back with a stamp on it saying not for service in excess of 1000V so I either need to do a course or stay on vessel with less voltage.

Main propulsion on bigger vessels

On smaller DE vessels or for secondary propulsion systems like transverse thrusters, DP devices like rudder propellers or pumpjets, the ship operators like to keep the voltage of the electrical side below 1.000 Volt. The thruster systems are mostly at 690 Volt or max. 960 Volt. Typical examples here are oil rig supply vessels, anker handling vessels / tugs and survey vessels with a high percentage of dynamic positioning.

On larger DE main propulsion systems, the voltage has to go up, due to the weight of the electric motors / alternators and the cables. And with larger cables, the losses get much higher.

Large DE cruise ships, ferries or merchant vessels can go up to 6.000 Volt, 11.000 Volt or even 15.000 Volt. This is for the same reasons, the voltage on long distance power lines is transformed to more than 100.000 Volt. Just to keep the cables thinner and reduce losses due to the high resistance in thicker "wires".

Watt is Volt x Ampere, i.e. higher voltage means lower amps. Easy as that. Adapting and controlling / regulating the frequency of the AC current at higher voltages is another story. But this is thin ice for me, I keep out of it .

I know it is BS but it would be interesting to see a 150 MW power transmission at 400 Volt. A lot of copper

But on ships, above 1000 Volt, everything gets more complicated, more expensive and more regulated (for good reasons). Big DE ships have additional specialized engineers for the high voltage stuff on board and normally the HV machinery is seperated from the MV or LV stuff.