Electric Propulsion on Catamarans

[colemj]

Originally Posted by boat_alexandra

This is completely false. Brushed motors will not be disabled.

If you are talking about brushed electrical motors in general, then this is false. We had brushed motors burn and melt their windings in our lightning strike.

Mark

[seandepagnier]

Originally Posted by colemj

If you are talking about brushed electrical motors in general, then this is false. We had brushed motors burn and melt their windings in our lightning strike.

Mark

I believe you, I stand corrected. A direct strike (depending on strength) could melt any type of motor, blow up gas cylinders, blow holes in the hull etc.. I was thinking of the more likely case of an indirect strike.


Also, I think using a switch to disconnect wires is a stupid idea since a million volts doesn't mind jumping across switch contacts much. Much better to have quick disconnect connector for wires so you can separate it by a much greater distance.

[nimblemotors]

Water in your fuel disables your diesel engines.
Make sure your boat is not around water to avoid the risks.

[smj]

Originally Posted by nimblemotors

Water in your fuel disables your diesel engines.

Make sure your boat is not around water to avoid the risks.

:-)


Sent from my iPad using Tapatalk

[Tropic Cat]

Originally Posted by boat_alexandra

Cheap brushless run 80-85% through most of their range. Cheap brushed motors 65-75%. Some brushless can achieve 90% or better.

True, but we all know that. I asked about the motor drive (electronics to operate the motor. Not the motor itself). I've been out of it for a while, but PWM motor controls were at 90% efficiency the last time I looked.

Originally Posted by boat_alexandra

This is incorrect. My system could drive the boat 2-3 knots forever as well as charge the battery with the excess solar input. Motor used 150 watts to go 2 knots, and 7 "50 watt" solar panels producing 250 watts.

How heavy is your boat??

Originally Posted by boat_alexandra

A gps will also be disabled, so I guess they are not usable in tropical climates (despite the fact that lightning strikes occur outside of "tropical climates" depending on season, and also don't often occur everywhere in tropical climates..)

No. If connected to 12 VDC, you're right. A handheld GPS on my salon table was unaffected by the lightning hit. However, everything connected to 12 volts was history

Originally Posted by boat_alexandra

There are _never_ times when you need an engine of any kind. ..

I believe I said "when things go bad out there". Not when it's perfect.

Sail enough, and it happens to everyone.

[nimblemotors]

From the anchor thread..

I avoided an ugly incident last week due to a mismanaged fuel valve by the dumb caption (me ) anyway ran from bimini straight tru to Nassau arriving in the harbor around 3:30 am. Just as I passed under the bridge both motors in my 44' my quit. The current was running hard and immediately swep us back under the bridge. I quickly deployed my 105lb mantus and thankfully it set Rite Now. Saving me from what could have been an ugly situation. The purchase price of that anchor was well worth it that night as I was able to turn the fuel valve bleed the fuel pumps and go on my way un scarred

Diesel engines are just too unreliable for use in a boat.

[yamez4u]

Your port motor had no starter? So how did you start your diesel? You precious diesel was just as disabled as anything else on your boat. Which is exactly my point lightning strikes damage random equipment, one of your motors survived and one did not. Both need a starter and alternator (unless you have other ways to charger your bank) so your diesels have more electric motors then an electric setup, and are zero less likely to be disabled. A lightning strike can damage odd things like thru hulls and leave the chart plotter alone. Or could take out every device on a boat. Both the electric motors and the diesels (that have multiply electric motors on them) need a working battery bank and working electric motors. In the case of the diesel a starter and an alternator, charge controller and a contact relay. All things your diesel and an electric drive system would need to work. Your comment that you diesel is some how less effected by lightning then an electric drive shows your lack of knowledge of just how important electric motors are to a modern boat, including boats with diesels.

[DotDun]

Originally Posted by yamez4u

Your port motor had no starter? So how did you start your diesel? You precious diesel was just as disabled as anything else on your boat. Which is exactly my point lightning strikes damage random equipment, one of your motors survived and one did not. Both need a starter and alternator (unless you have other ways to charger your bank) so your diesels have more electric motors then an electric setup, and are zero less likely to be disabled. A lightning strike can damage odd things like thru hulls and leave the chart plotter alone. Or could take out every device on a boat. Both the electric motors and the diesels (that have multiply electric motors on them) need a working battery bank and working electric motors. In the case of the diesel a starter and an alternator, charge controller and a contact relay. All things your diesel and an electric drive system would need to work. Your comment that you diesel is some how less effected by lightning then an electric drive shows your lack of knowledge of just how important electric motors are to a modern boat, including boats with diesels.

FYI, it's possible to hand-crank my diesels. No power required for the engine to run. The only thing lost is the oil pressure alarm and water temp alarm.

[44'cruisingcat]

Originally Posted by nimblemotors

Water in your fuel disables your diesel engines.
Make sure your boat is not around water to avoid the risks.

Whereas electric motors and water are just fine together?

[nimblemotors]

Originally Posted by 44'cruisingcat

Whereas electric motors and water are just fine together?

Umm yeah..don't you know ANYTHING about electricity??
This is the stupidest comment I've ever seen on this forum.

little DC motor under water - YouTube

[44'cruisingcat]

Salt water?

[44'cruisingcat]

Originally Posted by yamez4u

Your port motor had no starter? So how did you start your diesel? You precious diesel was just as disabled as anything else on your boat. Which is exactly my point lightning strikes damage random equipment, one of your motors survived and one did not. Both need a starter and alternator (unless you have other ways to charger your bank) so your diesels have more electric motors then an electric setup, and are zero less likely to be disabled. A lightning strike can damage odd things like thru hulls and leave the chart plotter alone. Or could take out every device on a boat. Both the electric motors and the diesels (that have multiply electric motors on them) need a working battery bank and working electric motors. In the case of the diesel a starter and an alternator, charge controller and a contact relay. All things your diesel and an electric drive system would need to work. Your comment that you diesel is some how less effected by lightning then an electric drive shows your lack of knowledge of just how important electric motors are to a modern boat, including boats with diesels.

A diesel doesn't need an alternator to run. And if it can be hand started, it doesn't need a starter motor either.

[yardie]

Originally Posted by 44'cruisingcat

Salt water?

An electron will find the least resistant path between the cathode and anode. If given the choice of sand and water it chooses water. If given the choice of fresh water and saltwater it choices saltwater. If given the choice of air and a talking, sack of meat it choices the meat. If given the choice of saltwater and metal it chooses metal. So what about salt water?

[44'cruisingcat]

Originally Posted by yardie

An electron will find the least resistant path between the cathode and anode. If given the choice of sand and water it chooses water. If given the choice of fresh water and saltwater it choices saltwater. If given the choice of air and a talking, sack of meat it choices the meat. If given the choice of saltwater and metal it chooses metal. So what about salt water?

So you reckon electrical equipment will work fine exposed to sea water? Good luck with that.

[socaldmax]

Originally Posted by 44'cruisingcat

Salt water?

The Secondary Propulsion motor on a 688 class fast attack sub is an electric motor in a rotatable pod that extends out of the bottom of the hull and provides high maneuverability in slow, dockside situations. It is always submerged, down to test depth.

They rarely, if ever, short out. I'm not aware of any that have.

Interestingly, the US Navy seems to be shifting to electric drive. The first major combatant to use electric drive was the DDG 1000 (Zumwalt-class destroyer). Since that has proven to be reliable and effective, the Ohio class subs (Ballistic Missile Subs, or boomers) will now be shifted to direct drive electric. The original design was twin steam turbines attached to a huge reduction gear driving a single shaft. The new design will generate more electricity and use electricity for primary and secondary propulsion.

While the Navy does a lot of R&D, they don't commit to a new design until well after it has proven itself. For years, subs were built with an older ESM system, then retrofitted with a newer ESM system because the original contract for that class specified the older ESM system, even though the newer system was tested and approved.

If they've already shifted DDGs and are going to shift SSBNs (critical for world dominance of the seas, called "diplomacy" in some circles) then all of the committees, R&D groups, Naval Architects and Engineers and contractors are positive that this is a better propulsion system.