The rough draft for Part IV of the Single Screw Series follows.
Single screw inboard boaters or those well versed in single screw
operation are invited to review my remarks, just in case I have done a
poor job of explaining something or (horrors! couldn't be!) have made
an obvious error. TIA

***********

The Taming of the Single Screw,
Part IV

In the first three installments of this series we examined the natural
forces of wind and current as well as the mechanical forces we can
generate and control with single screw technology. We have reviewed the
fundamental considerations involved in backing and filling to execute a
small-radius turn, controlling a single screw while going astern, and
making a landing under a variety of wind and current conditions. Simply
getting the vessel to the dock is only a portion of the task, of
course. It's important to consider how to properly secure the boat,
as well as safely depart the dock or float when it's time to get
underway again. Line handling is an important part of single screw
operation, both in securing a boat in its slip and providing additional
control options when docking or clearing in difficult conditions.

Basic Dock Lines:

1. The bow line will lead from a cleat or bollard on the foredeck,
often through a chock or hawse, and terminate at a cleat, piling, or
bull rail on the dock. When possible, most boaters will attempt to
select a mooring point slightly forward of the hawse, chock, or cleat
from which the bow line leaves the vessel. The primary function of the
bow line is to prevent the bow from blowing or drifting away from the
dock.
2. The stern line will lead from a cleat or bollard, often through a
hawse, at or near the transom of the vessel and should terminate
slightly aft of the vessel's position at the dock. The primary
function of the stern line is to prevent the stern from blowing or
drifting away from the dock.
3. The forward spring line will lead from a cleat or bollard, possibly
through a hawse, on the aft section of the hull to a mooring point well
forward. The primary function of the forward spring line is to prevent
the vessel from blowing or drifting astern at the dock. In some
instances, the forward spring line will be rigged from a point near the
midship where that aft spring line also originates.
4. The aft spring line will lead from a cleat or bollard, possibly
through a hawse, on the forward section of the hull to a point well
aft. The primary purpose of the aft spring line is to prevent the
vessel from blowing or drifting forward at the dock. In some instances,
the forward spring line will be rigged from a point near the midship
where the forward spring line originates as well.

The four lines listed above are the minimum number of lines required to
secure a boat in most situations. Breast lines may also be used, and
will lead from points forward, midship, or aft to mooring points
immediately adjacent on the float or pier.

On many boats, the bow and stern lines are of sufficient length that
only two lines need to be rigged for normal docking. In such cases,
once the bow line is secured the excess rope will be carried a midship
deck cleat or hawse and then secured to form the aft spring line.
The excess rope associated with a long stern line is likewise carried
to a midship cleat or hawse to form the forward spring.


Using dock lines for additional control when docking

In the ever elusive "ideal" docking conditions, the boat will come
to a complete stop properly located in the slip or alongside the float
or pier before any lines are passed ashore. When arriving at a mooring,
particularly in a busy public marina, it isn't unusual to be greeted
by a committee of volunteer line handlers. In most cases, the folks on
the dock catching the lines will be at least moderately helpful. An
alert helmsperson will want to monitor the activities of unknown line
handlers, as what a well meaning but unskilled helper assumes to be a
"useful" tug on the line may be working at cross purposes against
the skipper's docking procedure.

The more challenging the conditions encountered, the more likely it
will be that relying on additional control established by a dock line
will be critical to a smooth and successful landing.

Observations at the dock indicate that most boaters docking in benign
conditions will get the bow line ashore first, and once it is secured
some boaters will then power against that line to bring the stern to
the dock. While this is common practice, some of the more adept boat
handlers will send the aft spring line ashore first, as powering
against a secured aft spring line will tend to bring the boat into the
dock with a more parallel fashion. Setting the aft spring line first
becomes increasingly important as wind or current increase in an
"upstream" or "upwind" landing.

When forced to dock "downstream" or "downwind", with the wind
or current on the stern, getting the stern line ashore will be a high
priority. The wind or current will carry the stern away from the dock
unless secured fairly quickly. With a very strong wind or current on
the stern, it may be necessary to land the forward spring line first
and use reverse thrust to keep the vessel alongside the float or pier
until additional lines can be secured.

To the maximum practical extent, it is more desirable for onboard deck
hands to make at least the additional mooring hookups from aboard the
boat. It is never a preferred practice for deckhands to be leaping from
a moving boat: if the dock surface is slippery or there are obstacles
unseen in the dark it is far too easy to trip, and the consequences of
a deckhand falling into the rapidly closing gap between the unyielding
float or pier and perhaps a 10 or 20 ton boat can be deadly. Line
handlers unskilled in throwing a loop over a cleat can use a boathook
to get a braided loop secured while remaining aboard.

Breast lines can be important when docking single handed. Single handed
landings in challenging conditions are seldom pretty, but once a
midship breast line is secured that becomes a "pivot point" at the
dock and neither the bow nor the stern will blow off very far before
the single handed boater can get additional lines ashore.


Getting away from the dock:


Making a clean and accident-free departure can be even more challenging
than landing a boat. When making a landing, it is often possible to
change the direction of approach to compensate for wind and current.
When it's time to depart, the current may have reversed or the wind
changed and there is obviously no option to move the other side of the
float or reposition the boat 180 degrees before beginning the maneuver.


Once again, an examination of procedures likely to prove useful in
"perfect" conditions where wind and current are not considerations
will serve as a basis for considering the variations required in
upstream or downstream departures, as well as situations where a beam
wind is setting the vessel onto or off the dock.

It can be fairly easy to spot a novice boater attempting to depart from
a dock; all too often the boat is scraping along the face of the float
or pier while the new boater instinctively (and incorrectly) turns the
wheel and the rudder away from the dock in an effort to free the bow.
Many accidents occur when a departing boater manages to get the bow
free of the dock, but not at an angle sufficient to allow the stern to
clear a boat moored immediately ahead as the departing vessel gets
underway. Short of using a manual shove of the bow away from the dock
or engaging a bow thruster, it is normally much easier to get the very
maneuverable stern powered out into the fairway and then reversing away
from the pier or float.

Departing with no wind or current:

To free the stern in benign conditions, begin by turning the wheel and
the rudder hard over toward the dock. It may be useful to position a
fender about halfway along the bow curve. A short burst of forward
thrust will "kick" the stern into the fairway, and a second short
burst may be required to provide adequate clearance astern to begin
backing away from the face of the dock. The fender should protect the
most forward portions of the hull from scraping the dock as the boat
makes the "turn." Assuming the boat was landed on the "backs
to" beam, it wouldn't be unusual to need to create additional
clearance astern during this maneuver in order to be certain of
clearing other vessels moored on the same dock. Once a few feet away
from the face of the float or pier, opportunities for short bursts of
forward thrust can be used to increase the angle of the boat relative
to the dock and provide a greater margin of safety.

When well out into the fairway, and mindful that the stern will require
sufficient room to swing back toward the dock and or other boats moored
alongside as headway is established, the helm can be shifted away from
the dock, forward gear engaged, and the vessel can then be powered
away.

If later arriving vessels have been moored so closely that there is
very little room fore and aft to use for maneuvering the stern into the
fairway, powering forward against an aft spring line will exaggerate
the kick (or the "spring") of the stern into the fairway. If there
is no dockside line handler, this spring line can be looped around the
cleat with the bitter end secured aboard. Deckhands will need to be
quick about the release and retrieval of this line when the stern is
sufficiently clear and the helmsperson indicates he or she is ready to
power astern.

Departing "upstream":

With sufficient wind or current on the bow or the dockside forequarter
of the boat, it can be easier to free the bow than the stern. In such a
departure, the stern line is typically left secured until the wind or
current has carried the bow to perhaps a 30-degree angle from the dock.
Mindful that there is sufficient clearance to allow maneuvering room
alongside any vessels possibly moored ahead on the same float or pier,
engaging forward gear with the rudder hard over toward the dock will
allow the stern to follow the bow into the fairway.


Departing "downstream":

Wind or current directly astern or on the dockside aft quarter of the
boat can make it fairly easy to get the stern away from the dock and
into the fairway. As the stern begins moving and the wind or current
increases pressure on the dockside beam, achieving adequate clearance
astern is all but automatic. The potential problem with a downstream
departure can be a tendency for the boat to shift forward along the
face of the pier while the stern is being carried off, making the
downstream departure another maneuver in which an aft spring line can
be used to considerable advantage.


Departing with wind or current off the dock:

In a rare instance when the wind or current is pushing directly on the
dockside beam, clearing the dock can be easily accomplished by simply
casting off the lines and blowing or drifting sideways into the
fairway. Wind or current coming from a few points off the beam can be
utilized in the same manner, provided there is clearance fore or aft as
appropriate. Wind will carry the bow farther and faster than the stern,
so if it is important to be essentially parallel to the dock once clear
of vessels ahead or astern (such as in a narrow fairway situation) it
can be useful to loosen the stern lines first and give the stern a
short "head start" in the process. Loosening the bow lines a moment
after the stern lines should allow the bow to "catch up" before the
stern is too far away from the dock.


Departing with wind or current on the dock:

Being "pinned" against the dock, particularly with a single screw,
is one of the more challenging problems to solve. A practical
consideration is that if the wind is blowing at some gale or near-gale
force that would make it extremely difficult to get away the prudent
decision (and one that may have little or nothing to do with docking)
will often be to stay put in the harbor until the winds moderate. In
light, moderate, or even strong winds it's certainly possible to
clear the dock against a wind on the outside beam. The technique
depends heavily upon the use of an aft spring line, bursts of forward
thrust with the rudder hard over toward the dock, and attempting to get
the stern directly into the wind as much as possible. When the maximum
stern clearance is achieved with the largest achievable margin between
the stern and any vessel moored aft, shift into reverse gear and apply
substantial power. It will be important to get well out into the
fairway before attempting to turn the rudder away from the dock and
power off; the same wind that was holding the vessel against the dock
will be shoving the boat back across the fairway in those moments
before headway and steerage are substantially realized.


Bow and stern thrusters:

It can be observed that adding a bow and/or stern thruster technically
removes a boat from the "single screw" category, (thrusters have
propellers), but a growing number of new single screw boats are being
rigged with thrusters as standard equipment and thrusters are a popular
"upgrade" on older single screw vessels. Some boaters prefer stern
thrusters, a few boaters insist on a combination of bow and stern
thrusters, but in cases where only one thruster is installed the
majority of single screw boaters will elect to use a bow thruster. A
properly employed prop and rudder is surprisingly capable of
"thrusting" the stern, but a bow thruster is the only device
capable of moving the bow with any degree of independence from the
stern.

Bow thrusters can be used effectively to keep the bow in line when
going astern in a single screw, so backing into a slip can be executed
with greater control. Using a bow thruster in a very tight turn
effectively moves the "pivot point" aft and reduces the radius
required to make a 180 degree or larger turn. When wind or current
threatens to foul up a landing by carrying the bow away, a touch of the
thruster control can often allow a landing to continue that would
otherwise need to be aborted and re-attempted.

Bow and/or stern thrusters undoubtedly make some previously impossible
maneuvers easy to accomplish, provide an additional margin of safety,
and can be useful tools to enhance the abilities of a skillful
helmsperson. That said, thrusters will be most effectively used by
boaters who understand the physics and practices of single screw
helmsmanship well enough to do without a thruster in the majority of
cases. The author remembers a situation observed at the marina in Lund,
BC when a charter boater experienced a mechanical failure of the bow
thruster on a single screw trawler.
It was evident that the panicking charter boater was absolutely unable
to dock the boat without a thruster. An impromptu rescue committee,
consisting primarily of owners of those boats directly in the hapless
skipper's path, managed to get enough lines and fenders out to
manually warp the trawler to the dock. The moral of this incident, and
undoubtedly scores of similar situations in our region each year, is
that even boaters able to rely on thrusters to assist in close quarter
maneuvering would be well advised to practice traditional single screw
skills. Thrusters are great, (I certainly enjoy mine), but won't ever
be an acceptable substitute for basic, skillful, helmsmanship and line
handling.

Short Wave Sportfishing wrote:


Breast lines can be important when docking single handed. Single handed
landings in challenging conditions are seldom pretty, but once a
midship breast line is secured that becomes a "pivot point" at the
dock and neither the bow nor the stern will blow off very far before
the single handed boater can get additional lines ashore.

Hmmmm - I'm having a little trouble visualizing this - maybe I have a
mistaken idea of what a breast line is.

A breast line in a line that leads directly to the mooring and will be
secured without being led forward or aft. I find that when I'm single
handed the most useful thing to do is to get a short line from the
midship hwse secured to something, as there is only a limited amount of
blowing off that can occur to either the bow or stern if the middle of
the boat is secure.
Securing the bow line first can (and has) resulted in the stern getting
blown back into the fairway, and that's the same with the stern.

If later arriving vessels have been moored so closely that there is
very little room fore and aft to use for maneuvering the stern into the
fairway, powering forward against an aft spring line will exaggerate
the kick (or the "spring") of the stern into the fairway. If there
is no dockside line handler, this spring line can be looped around the
cleat with the bitter end secured aboard. Deckhands will need to be
quick about the release and retrieval of this line when the stern is
sufficiently clear and the helmsperson indicates he or she is ready to
power astern.

I had to think about this for a minute - it's correct, but it seems
overly complex.

Mindful that there is sufficient clearance to allow maneuvering room
alongside any vessels possibly moored ahead on the same float or pier,
engaging forward gear with the rudder hard over toward the dock will
allow the stern to follow the bow into the fairway.

A minor nit pick and probably entirely my fault, but I don't own a
boat with a rudder - the Halman doesn't count. :)

When you say rudder hard over towards the dock, do you mean turn the
wheel towards the dock or the rudder towards the dock.

Stupid question I know, but...

If you're steering a modern boat with a wheel, the rudder moves in the
same direction as the wheel. To set the rudder toward the dock, turn
the wheel toward the dock. There was a time when this was typically
reversed, and that's a subject that often comes up in the discussion of
Titanic minutiea; "was the helm ordered turned in the wrong direction
immediately prior to colliding with the iceberg?".