[Varley]

I don't know about sensitive switchgear as an enabling technology although I remember the earlier SCR SGs' DC links had special SC protection (both the expert makers later 'simply' killed the inverter or rectifier rather than tripped the DC circuit). Engineers take pride in making for 10 bob what any fool can knock up for a fiver but, like SOLAS they are no longer satisfied with the milk, cream and butter but want the whey too. To this end they have developed breakers that can anticipate where a rising current would otherwise end and so interrupt it at a lower level. Goody, goody we can now reduce the cost to nine Shillings eleven and three farthings, but what happens if the breaker fails to open? The scantlings now might not survived the fault with worse consequences.

Whilst not sailing with electrical propulsion I did have a few in the fleet - all, bar two, asynchronous motors. One which used synchronous motors but with conventional pony motor starting (perhaps strange is better in this context) with no nasty high rise times so no unusual problem with harmonics.

The remaining odd man out was DC drive. Poorly designed with SCR based converter from a dedicated propulsion alternator as if it was a shore based arrangement with no control over the supply (much less demanding and economic would have been to control the excitation of the dedicated propulsion alternator and have a simple rectifier). But I digress. It was so noisy, especially at half power where then switched voltage was maximum, that it basically needed smoothing to iron out the spikes as you mother's radio would have had only bigger, of course (that is bigger smoothing circuit not bigger mother you will understand).

Although accused of being a Luddite I am not, either (well, I don't think so). I think Victorian describes me better with more emphasis on not getting into trouble than having so much regulation around how one gets out of it.