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CaptBones · 12-05-13, 05:58 PM

Well, I don't really want to "torpedo" Sailor Steve's logic or contradict Jimbuna's experience...but...steering with astern way on is extremely easy and very accurate in twin-screw destroyers and "Fleet" type submarines (probably just as good for U-Boats). I once backed the USS Laffey (DD 724) through the inner harbor of Grand Harbor, Valleta, Malta, to "Med Moor" at Fort St. Angelo. The pivot point when going ahead is about one-third of the ship's length back from the bow (for surface ships) and a little further aft for "Fleet" type submarines; that's why their bridges are located where they are...just forward of the "ahead" pivot point. One action you'll see that differentiates an experienced conning officer from a "nugget" is that the "nugget" gives a rudder order and watches the bow move, the old salt gives a rudder order, steps out to the opposite bridge wing to check the swing of the stern, then comes back to the centerline pelorus and watches the bow.

The pivot point in the mentioned ship types moves forward (toward the bow) when going in the astern direction with way on. When starting to move astern, and having little way on, it's different; the location of the pivot point isn't as significant as the effect of the prop wash, or lack of wash, against the rudder(s). The trick to maneuvering a twin-screw ship, without good way on, either standing without moving ahead or astern, or starting to move in either direction, is to "twist" the ship by operating the engines in opposite directions. You the turn the rudder away from the direction you want the stern to go, otherwise it's just a big "barn door" keeping the stern from moving where you want it to move.

As alluded to, handling a single-screw ship (or boat) is quite different. I had the same kind of problems with my Watkins 26 (8hp Yanmar one-lunger) getting into and out of the slips at the Washington Sailing Marina. Usually, the screw turns clockwise (looking from stern-to-bow) when going forward, which gives the stern a push to starboard when starting to move ahead and a definite push to port when backing down. I won the Pacific Fleet Shiphandling Award in 1974 by backing a single-screw "Knox" Class Frigate to starboard while making a "two bell" landing maneuver at berth B-26 in Pearl Harbor. I taught that maneuver to the students at Surface Warfare Officer School in San Diego for several years after that..."The Book" says it can't be done.

12-05-13, 05:58 PM	#10
CaptBones The Old Man Join Date: Nov 2010 Location: Rockton, IL Posts: 281 Downloads: 208 Uploads: 0	Not exactly correct... Well, I don't really want to "torpedo" Sailor Steve's logic or contradict Jimbuna's experience...but...steering with astern way on is extremely easy and very accurate in twin-screw destroyers and "Fleet" type submarines (probably just as good for U-Boats). I once backed the USS Laffey (DD 724) through the inner harbor of Grand Harbor, Valleta, Malta, to "Med Moor" at Fort St. Angelo. The pivot point when going ahead is about one-third of the ship's length back from the bow (for surface ships) and a little further aft for "Fleet" type submarines; that's why their bridges are located where they are...just forward of the "ahead" pivot point. One action you'll see that differentiates an experienced conning officer from a "nugget" is that the "nugget" gives a rudder order and watches the bow move, the old salt gives a rudder order, steps out to the opposite bridge wing to check the swing of the stern, then comes back to the centerline pelorus and watches the bow. The pivot point in the mentioned ship types moves forward (toward the bow) when going in the astern direction with way on. When starting to move astern, and having little way on, it's different; the location of the pivot point isn't as significant as the effect of the prop wash, or lack of wash, against the rudder(s). The trick to maneuvering a twin-screw ship, without good way on, either standing without moving ahead or astern, or starting to move in either direction, is to "twist" the ship by operating the engines in opposite directions. You the turn the rudder away from the direction you want the stern to go, otherwise it's just a big "barn door" keeping the stern from moving where you want it to move. As alluded to, handling a single-screw ship (or boat) is quite different. I had the same kind of problems with my Watkins 26 (8hp Yanmar one-lunger) getting into and out of the slips at the Washington Sailing Marina. Usually, the screw turns clockwise (looking from stern-to-bow) when going forward, which gives the stern a push to starboard when starting to move ahead and a definite push to port when backing down. I won the Pacific Fleet Shiphandling Award in 1974 by backing a single-screw "Knox" Class Frigate to starboard while making a "two bell" landing maneuver at berth B-26 in Pearl Harbor. I taught that maneuver to the students at Surface Warfare Officer School in San Diego for several years after that..."The Book" says it can't be done.