"Roll, roll, roll your boat..."

[BigDon]

Hey! Before this gets ugly it's been at least five years since I did any serious reading on modern warship design.

But it's still fun to argue.

[Gigabyte]

I find it's more fun to find out the truth.

[captain swoop]

Submarine captains were aware of the problem with batteries. Crews were killed by gas from batteries. Look at the accounts of the X-Craft mini subs that attacked the Terpitz, at least one of them was abandoned because of gas. Also U-Boats and Allied subs had to be abandoned after similar damage and problems. Look at the SOLAS regs for batteries on ships, they insist on gas tight compartments, gas larms and venting. Do you realise how much current is needed to power an entire cruise ship for half an hour? Do tyou know what the current demands would be for the propulsion motors of a Diesel/Electric or Turbile/Elexctric powered boat are?


Looking through SOLAS and COLREG I can't see anything that specifies that a ship needs any battery power other than to provide emergency lights for evacuation and power for distress transmission.

Emergency lighting is powered by a local battery charged from the ships main supply. Remote supply from a bank of batteries can be interupted just like a generator supply so in that sense yes, there are batteries aboard.

Show me one major ship that has battery power to the engines or main electrical distribution system.

[sarongsong]

Yes, but what are they driving? The same props that the turbines are connected to? Or auxiliary thrusters?

So far, I've only seen specs/references to twin controllable pitch 17½' props (from Rolls Royce). No mentions of auxiliary thrusters.

(I'm surprised to not find some dissections of this ship on Popular Mechanics / Science sites, BTW; they usually go cover-story nuts over these types of things.)

[captain swoop]

thrusters are for positioning, they allow you to go alongside or turn a ship withoutpaying for Tugs.usualy at the bow and stern, there are several types, some are tunnels through the hull, some retract and some can be steered. They are usualy hydraulic or electric powered. Some of the steered ones can be used for propulsion but the need a heck of a lot of power, ceetainly not battery power.

[captain swoop]

Just to add, Bow and Stern Tunnel thrusters on a decent size ship are rated at something like 400- 2000Kw Steerable 'Azimuth' Thrusters as used for Tugs and positioning systems on drilling ships or survey ships are about 2000 - 4000Kw.

Propulsion motors are in the order of 20000 or 30000 Kw and up
Stadt start with systems about 2500Kw for small stuff like Tugs and Workboats and go up from there.

That's a heck of a battery.

[Gigabyte]

Show me one major ship that has battery power to the engines or main electrical distribution system.

You didn't answer the question. Want to bet? If you are so sure you are right, lets make it interesting.

(Just a fun bet, not money)

I say there are very large modern ships, (that use electric power for propulsion), that have battery back up (in case of catastrophic loss of power generation).

The batteries are large and powerful enough to run the ship's key electrical services including lighting and emergency steering, for at least 30 minutes.

How sure are you that you are right, and I am wrong?

[captain swoop]

Now you have changed your claim. I have already posted that 'key circuits' will operate, the emergeancy lighting will operate on battery as do other emergency systems. What won't operate are the main lighting circuits, power circuits, propulsion, air conditioning, water makers etc. Emergeancy lighting and evacuation signs are lit by battery power but not from a central huge bank of batteries. SOLAS regulations say they have to be self powering, What do you claim 'emergency steering' is? Steering is redundant if you have lost power, your rudder won't do anything if there is no water moving past or you aren't moving through the water.


Show me the ship you are refering to please.

[BigDon]

I find it's more fun to find out the truth.

*Raspberry*

How can you know the truth of anything you haven't seen? You're just Googling stuff.

[Gigabyte]

Of course. I highly recommend it. It's way better than making stuff up.

[Gigabyte]

What started this:

More wrong. On modern electric powered craft, the ships key electronics, electrical services, lighting and emergency steering all run on a huge UPS system. Cruise ships are required to have at least a half hour emergency power.

What I said today:

I say there are very large modern ships, (that use electric power for propulsion), that have battery back up (in case of catastrophic loss of power generation).

The batteries are large and powerful enough to run the ship's key electrical services including lighting and emergency steering, for at least 30 minutes.

How sure are you that you are right, and I am wrong?

What you said today:

Now you have changed your claim.

Really? You want to bet on that?

[BigDon]

Of course. I highly recommend it. It's way better than making stuff up.

You seem to be confusing your terms "making up" and "remembering". You might want to see to that.

[Gigabyte]

Unless you worked on a modern electric ship, how are you remembering how it works?

[SolusLupus]

When were the changes made, Robinson?

[sarongsong]

...I say there are very large modern ships, (that use electric power for propulsion), that have battery back up (in case of catastrophic loss of power generation).
The batteries are large and powerful enough to run the ship's key electrical services including lighting and emergency steering, for at least 30 minutes...

...Show me the ship you are referring to please.

Audience chant: "Show us the ship! Show us the ship!..."

[captain swoop]

Because the propulsion is by electric motors doesn't make the ship any more or less 'Electric' My dad was an engineer on Canberra for a while, that had electric propulsion back in the 60s. It used Steam Turbines to power the generators, Modern ships use Diesel as the power for economy reasons.
Steering gear was hydraulic, the power for the hydraulics came from power take off from the main shafts and backup diesel sets for when the shafts weren't turning (Hydraulics are used for all kinds of things on ships like capstans, hatches, stabilisers etc). No batteries on the steering.
All the ships I served on depended on electricity for their operation, Fans, Pumps, Navigation, Weapons, Sensors, Galley ranges. If they lost electical supply they everything but the emergency lighting was dead.
You claimed that 'key electronics, electrical services, lighting and emergency steering all run on a huge UPS'
Now you say 'key electrical services and lighting' as well as something you call 'emergency steering'

I say that the 'key services' are the emergency lights. They are seperate from the main lighting systems, some communications systems are also on a battery supply but like the lights it is local to them not a remote 'UPS' Remote emergency supplies can fail, they rely on wires to connect them. Class A regs require that the the EPIRB beacon DSC and ATIS (all the distress and position systems) are on a local backup supply, either battery or generator. EPIRB beacons are usualy on battery anyway.
I don't know what 'emergency steering' system you mean. If you have lost all power then you have no steering. If your Props stop you can't steer.

I want you to give me an example of an 'Electric' ship that has more than these systems running off battery then I will be happy.

[Gigabyte]

Audience chant: "Show us the ship! Show us the ship!..."

I'm waiting to see if the critics are willing to bet. I know they are wrong. They make claims but when I want to bet on it, they want to see the evidence first.

It doesn't work like that. If you are sure you are right, then take the bet.

It makes it more interesting.

[captain swoop]

We aren't here to bet. If you have it show it.

I found a link to a company that provide shaft alternators executed in such a way that, in case of emergency, they can be used as emergency propulsion motors but they are fed from the Diesel sets, not batteries.

[Gigabyte]

We aren't here to bet.

Nope, and I bet it doesn't have regenerative braking!

Interesting.

[captain swoop]

Interesting.

Right, you equate a joke comment by Dr Who with a serious bet?

Interesting.

[Gigabyte]

I said it was a fun bet, not serious. Did you miss that?

You didn't answer the question. Want to bet? If you are so sure you are right, lets make it interesting.

(Just a fun bet, not money)

See?

[Gigabyte]

Because I am all about the fun. And I consider learning new stuff fun. Shucks, even if I lose, I still learn something new. That's what makes it fun.

[Gigabyte]

Show me one major ship that has battery power to the engines or main electrical distribution system.

That could be a problem. Do you live near a major cruise ship port? I do. I could meet you there. We could do lunch, tour the ships. It would be fun.

[Gillianren]

Gee, someone used a figure of speech. Who wasn't the person/people with whom you're "making a bet."

[sarongsong]

Hey Robinson, you're in the Science Forum now, not Fun-n-Games.

[SolusLupus]

Hey Robinson, you're in the Science Forum now, not Fun-n-Games.

For once, sarongsong and I agree.

What's the term? "Put up or shut up"?

[Gigabyte]

Hey Robinson, you're in the Science Forum now, not Fun-n-Games.

I know that. Which is why all my information is from scientific sources. I don't make things up. In a science/technology thread.

[Gigabyte]

Gee, someone used a figure of speech. Who wasn't the person/people with whom you're "making a bet."

And your point is?

[PetersCreek]

Hey Robinson, you're in the Science Forum now, not Fun-n-Games.

This is quite correct. Robinson, if you're able to support your assertion, then by all means do so...but enough of the coy betting games. It's disruptive.

[Gigabyte]

In that case, what would you accept as proof? That a large modern ship that uses electricity has battery backup to provide emergency power?

Can you go look at one with me? That is clearly absurd, asking me to show you one. So what is it you want? What will you accept as evidence that I have clearly stated the truth? And that those making claims that are not true, are wrong? As I stated.