Wow, this story, if true, is appalling. According to the Daily Mail, the Royal Navy is making ships sail home from deployments at reduced speeds in order to conserve fuel. Now, a ship's cruising speed is nothing like it's flank speed. Nobody runs at the max all the time because it would severely limit range or lead to insane fuel bills. It is a bit hard to tell from the facts presented here if this is a misunderstanding or if it is a real situation.
The Royal Navy is so strapped for cash that some crews returning home from overseas operations are being forced to ration fuel by sailing at half speed.
Frustrated sailors who have been away from their families for months say they are often taking days longer to get back to the UK because of the cost-cutting practice.
And if ships arrive back in Britain in the evening, they can be forced to moor offshore overnight before entering port because the Ministry of Defence cannot afford to pay overtime to dock workers.
A former Royal Navy weapons engineer who left the service less than six months ago said: "Coming back off trips away, you’d do 18 or 20 knots, but it’s not unheard of to do 12 because we have to save fuel.
"It can add days on to your trip away, and that’s important when you’ve been away for many months.
"There’s nothing worse than coming back across the Atlantic, bobbing around and knowing you could have been home a week earlier.
"You just get very frustrated and very annoyed when you try to explain to your children why Daddy’s not coming home for another night."
Armed Forces Minister Adam Ingram said he would ask the MoD to investigate the claims.
He added: "That should not be acceptable."
An MoD spokesman said ships returning from overseas duty travelled at about 14 knots to conserve fuel and prevent the need for too frequent refuelling.
18 to 20 sounds reasonable, 12-14 sounds very slow for a naval vessel. There have been other stories that indicate that the Royal Navy is in dire financial straights at the moment. That is not a good thing for one of the two navies who have made freedom of the seas the rule rather than the exception in the world.
I presume the aerodynamics of ships are similar to aircraft when it comes to drag — i.e. drag is related to velocity squared since air and water are both fluids and behave similarly (in general terms).
The WWII Lexington for example, was designed to go 10,000 miles between fill ups at 10 knots. At 30+ knots, that would have dropped considerably.
At 30 knots you’re starting to get some measurable air aerodynamic drag as well as from the water. I’m sure the water swamps that, but it all adds up.