docking seamanship 207
boat’s turning circles? You should have noticed that your boat can make a
tighter pivot in the direction of its propeller hand. To understand why, let’s
break it down.
Assume your boat has a right-handed prop and you want to pivot to the
right. In forward gear, prop walk tries to move the stern to the right (opposite
the direction you want to turn), but in forward gear your prop wash is directed
onto the rudder blade, which is hard over to the right. Since the force of the
prop wash on the blade is much stronger than prop walk, your turn to the right
begins or proceeds as planned. When you shift into reverse, the prop wash is
directed forward, not aft, and no longer impinges on the rudder blade. Since
your boat has little or no forward or backward motion, there is therefore no
flow of water over the rudder, and the rudder is effectively taken out of the
equation. That leaves prop walk in control, and prop walk in reverse gear
pushes the stern to port and the bow to starboard—exactly what you want to
have happen. Prop walk works with you to help pivot the boat.
Th is doesn’t mean you can’t pivot left with a right-handed prop—only
that it’s more diffi cult and will require a turning circle of larger diameter. By
the same token, a single-screw boat with a left -handed prop will make tighter
pivots to port than to starboard. Use this information when deciding in which
direction to execute a tight maneuver in a narrow canal, channel, or basin. All
other things being equal, the skipper on a boat with a right-handed propeller
would chose to pivot to the right.
MARINA ENTRY AND EXIT STRATEGIES
When you enter or leave a marina, you oft en have little room to maneuver. Th e
space is tight to begin with, and you need to contend with boats moving in
and out of the channel, slips, and docks. Use the following checks to prepare
for most any situation you might encounter.
Check wind and current. Use fl ags, waves, or wind indicators on boat masts
to get an idea of wind conditions inside the marina. If sailing in, this is critical
for decision making (see “Working into a Slip under Main or Headsail” below).
If under power, this enables you to judge which slip or dock approach you need
to use. If your engine fails, you will know which way your boat will drift. Study
the bases of pilings for clues to current fl ow. Current tails (streams that fl ow off
a piling) reveal current strength and direction. If in doubt as to whether cur-
rent or wind is the stronger element, stop the boat for a moment to identify the
stronger of the two.
Locate pivot areas. Look for pivot areas for backing and fi lling. Remember
that on a boat with a right-handed propeller (which is the norm), the stern
walks to the left in reverse gear, and the boat therefore turns better to the right.
Th us, you should scope out a pivot area on the left side of a constricted basin