In the Navy what is the difference between "standard rudder," or "full rudder" or "hard rudder"?

I was watching the movie “Greyhound” and these terms were used. What do they mean?

RIGHT (LEFT) FULL RUDDER usually means 30 degrees on the rudder angle indicator.
HARD RIGHT (LEFT) RUDDER means put the rudder over to the right the maximum degrees allowed by that class of ship.
RIGHT (LEFT) STANDARD RUDDER varies on different ship classes. It is the designated number of degrees of rudder angle that causes the ships of that class to turn within a prescribed distance, called the ship’s standard tactical diameter. You must find out what standard rudder is on your ship.

from Orders to the Helmsman

Something else I thought I knew but didn’t really…:slight_smile:

I know some big vessels like cruise ships are now rudderless. Are any significant naval ships? If so, do they stick with the rudder terminology or have developed something specific?

Former qualified Officer of the Deck (OOD) on a submarine here…

(The OOD generally has the conn on a warship, meaning that’s the person who gives orders to the helmsman. Also, now that I think about it, I also qualified as a helmsman on a surface ship back when I was a midshipman.)

So anyway, on a submarine, we generally ordered either a full rudder (usually when going relatively slow) or a certain number of degrees (like “Right 5 degrees rudder”). I don’t recall ever ordering a “standard rudder.”

Other helm orders included “Rudder amidships,” meaning to bring the rudder back to zero degrees; and “Shift your rudder,” meaning to shift the rudder to the exact opposite of the previous order, like from right 5 degrees rudder to left 5 degrees rudder.

Orders are given in a specific format with the order repeated back to a avoid any misunderstandings, as follows:

OOD: “Helm, right 5 degrees rudder.”
Helmsman: “Right 5 degrees rudder, aye, sir.”
[Helmsman moves rudder to right 5 degrees.]
Helmsman: “Sir, my rudder is right 5 degrees.”
OOD: “Very well.”

Instead of just giving a rudder order, the OOD will often order a specific heading, ordering something like “Helm, come right to course 095.” Or sometimes this order will follow a given rudder order.

Lastly, hard rudder orders are almost never given except in an emergency situation (like trying to avoid a collision). That’s because putting a rudder over hard into the stops runs the risk of jamming the rudder in place.

What about “Five degrees down bubble!” Is that really (still) a thing?

I believe the standard format in Russian submarines was to use a Scottish accent, because after extensive research they found this to be the clearest when there’s a lot of background noise.

Assuming you’re talking about a submarine :wink:, yes, more or less. The up or down angle of a submarine is controlled by the [diving] planes. The stern planes have the greatest effect on the angle of the ship, with the fairwater or bow planes used for finer control.

Instead of ordering a specific angle on the planes themselves, the operator of the stern planes will instead be ordered to maintain a specific up or down angle on the ship. Then, similar to orders to a helmsman to come to a new course, an order to come to a new depth is given to the planesmen (i.e. “Make your depth 285 feet.”)

On older submarines like I was on, depth orders go through the Diving Officer of the Watch (DOOW) — I hear that newer submarines eliminate this in favor of a pilot and a co-pilot.

Ideally a given depth can be maintained with minimal inputs from the planes and a neutral angle on the ship. (Note that the effectiveness of the planes and the angle of the ship are greatly affected by the forward speed.) The other adjustment that can be made is adding, removing, or moving ballast water amongst the variable ballast tanks (VBTs).

I always heard “Right 5 degrees rudder, helm aye."

I’ve heard that as well (meaning both). I wouldn’t have had an issue with either version, so long as the order was properly repeated back.

Your version is probably preferable in that the helmsman is identifying themselves in the repeat-back.

Do both the rate of heading change, and the turn radius, depend on the speed of the ship? I.e., 5 degrees rudder changes heading at X rate with 1/3 speed, but some multiple of X rate when at flank?

I love this board.

What are the planes on the conning tower called?

Fairwater planes. And for what it’s worth, the conning tower is now called the “sail.”

On newer submarines, starting with the improved Los Angeles-class (688-I) that I served on, the fairwater planes were replaced with retractable bow planes. The main reason was to facilitate under-ice operations so that the sail could easily break through the ice. The alternative on previous classes of subs (like the Sturgeon-class) was to rotate the fairwater planes to vertical, but this was reportedly problematic (like damage to the planes when surfacing though the ice).

What kind of ice thickness could you break through?

The rate of heading change definitely increases with increasing speed at a given rudder angle. On the other hand, for a given rudder angle, I don’t believe the turning radius is significantly affected by speed, because at higher speeds the rudder is more effective.

I was on three 688s. You?

Hey. Side Topic. Can ‘Greyhound’ be watched on any other platform than iHugeMonthlyBill?

It seems like a good movie, but paying another monthly bill is silly.

mrAru was on the USS Spadefish [one of the Sturgeons] the USS Miami and the USS San Juan.

[And the San Juan sort of shortened the sail popping up through the ice on her first ICEX]

Thanks, Robby.
That wasn’t a problem for Rock Hudson in “Ice Station Zebra”. :slight_smile: