02-20-2007, 12:15 PM
[font "Verdana, Arial, Helvetica"][#000080][size 2]The proper name of the maneuver in question is "Back and Fill". The execution of the maneuver depends on whether or not you have a right hand screw (turns clockwise in forward) or left hand screw (turns counterclockwise in forward). For our example we will assume a right hand, single screw boat. We will also assume favorable conditions i.e. lack of significant wind and/or current.Using the following method you should be able to turn a single screw boat in slightly more than its length.[/size][/#000080][/font]
[font "Verdana, Arial, Helvetica"][#000080][size 2]![[Image: back_fill.gif]](http://www.boatsafe.com/nauticalknowhow/back_fill.gif)
You should start the maneuver at idle speed toward the left side of the channel (figure 1.). [/size][/#000080][/font]
[font "Verdana, Arial, Helvetica"][#000080][size 2]When ready to turn, put the rudder hard to starboard. As the bow begins to turn (figure 2.).[/size][/#000080][/font]
[font "Verdana, Arial, Helvetica"][#000080][size 2]Shift to reverse which will, because of the prop walk, start the stern moving to port (figure 3.).[/size][/#000080][/font]
[font "Verdana, Arial, Helvetica"][#000080][size 2]Once you have checked forward momentum, but not the momentum of the bow movement, shift back to forward (figure 4).[/size][/#000080][/font]
[font "Verdana, Arial, Helvetica"][#000080][size 2]The bow will continue to smoothly turn around the pivot point. One more shift to reverse should complete the turn (figure 5.) .[/size][/#000080][/font]
[font "Verdana, Arial, Helvetica"][#000080][size 2]You do not want to make headway or sternway but simply pivot with a continuous motion. It may take more forward and reverse shifts than the graphic illustrates to continue pivoting until you have made the 180ยบ turn and are headed out of the channel (figure 6.).[/size][/#000080][/font]
[font "Verdana, Arial, Helvetica"][#ff0000][size 2]Important Notes:[/size][/#ff0000][/font] [indent] [ul] [li][size 2][font "Verdana, Arial, Helvetica"][#000080]Keep the rudder hard to starboard at all times.[/#000080][/font] [/size] [li][size 2][font "Verdana, Arial, Helvetica"][#000080]Stop for a brief second in neutral between shifts.[/#000080][/font] [/size] [li][size 2][font "Verdana, Arial, Helvetica"][#000080]Only stay in gear long enough to continue the pivoting motion, not long enough to gather headway or sternway.[/#000080][/font] [/size] [li][size 2][font "Verdana, Arial, Helvetica"][#000080]If you have other than ideal conditions, you may need to use a [/#000080][/font][font "Verdana, Arial, Helvetica"][#ff0000]quick and short[/#ff0000][/font][font "Verdana, Arial, Helvetica"][#000080] burst of throttle to help push the bow and stern around. [/#000080][/font][/size] [li][size 2][font "Verdana, Arial, Helvetica"][#000080]With a left hand screw boat you would do the procedure in the completely opposite direction, i.e. start on right side, and rudder hard to port.[/#000080][/font] [/size][/li][/ul][/indent]
[font "Verdana, Arial, Helvetica"][#000080][size 2]A side note from Bob Reardon, "Many down-east or lobster-type boats have left handed props. This is a reason: Working lobster boats usually have a working helm aft on the starboard side. Backing to starboard makes their life easier."[/size][/#000080][/font]
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[font "Verdana, Arial, Helvetica"][#000080][size 2]
You should start the maneuver at idle speed toward the left side of the channel (figure 1.). [/size][/#000080][/font] [font "Verdana, Arial, Helvetica"][#000080][size 2]When ready to turn, put the rudder hard to starboard. As the bow begins to turn (figure 2.).[/size][/#000080][/font]
[font "Verdana, Arial, Helvetica"][#000080][size 2]Shift to reverse which will, because of the prop walk, start the stern moving to port (figure 3.).[/size][/#000080][/font]
[font "Verdana, Arial, Helvetica"][#000080][size 2]Once you have checked forward momentum, but not the momentum of the bow movement, shift back to forward (figure 4).[/size][/#000080][/font]
[font "Verdana, Arial, Helvetica"][#000080][size 2]The bow will continue to smoothly turn around the pivot point. One more shift to reverse should complete the turn (figure 5.) .[/size][/#000080][/font]
[font "Verdana, Arial, Helvetica"][#000080][size 2]You do not want to make headway or sternway but simply pivot with a continuous motion. It may take more forward and reverse shifts than the graphic illustrates to continue pivoting until you have made the 180ยบ turn and are headed out of the channel (figure 6.).[/size][/#000080][/font]
[font "Verdana, Arial, Helvetica"][#ff0000][size 2]Important Notes:[/size][/#ff0000][/font] [indent] [ul] [li][size 2][font "Verdana, Arial, Helvetica"][#000080]Keep the rudder hard to starboard at all times.[/#000080][/font] [/size] [li][size 2][font "Verdana, Arial, Helvetica"][#000080]Stop for a brief second in neutral between shifts.[/#000080][/font] [/size] [li][size 2][font "Verdana, Arial, Helvetica"][#000080]Only stay in gear long enough to continue the pivoting motion, not long enough to gather headway or sternway.[/#000080][/font] [/size] [li][size 2][font "Verdana, Arial, Helvetica"][#000080]If you have other than ideal conditions, you may need to use a [/#000080][/font][font "Verdana, Arial, Helvetica"][#ff0000]quick and short[/#ff0000][/font][font "Verdana, Arial, Helvetica"][#000080] burst of throttle to help push the bow and stern around. [/#000080][/font][/size] [li][size 2][font "Verdana, Arial, Helvetica"][#000080]With a left hand screw boat you would do the procedure in the completely opposite direction, i.e. start on right side, and rudder hard to port.[/#000080][/font] [/size][/li][/ul][/indent]
[font "Verdana, Arial, Helvetica"][#000080][size 2]A side note from Bob Reardon, "Many down-east or lobster-type boats have left handed props. This is a reason: Working lobster boats usually have a working helm aft on the starboard side. Backing to starboard makes their life easier."[/size][/#000080][/font]
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