3.2.2 Arrangements for Breast Lines
Breasl lines are effective iD holdi ng the ship against transverse forces; they also are most effective
in restraining the yawing tendency of a vessel which is i.nduced by wind, current, etc., acting on the
ship. However. to be most effective Ln restraining tile yawing tendency, issue points for breast lines
should be as far forward and aft as pos~ible. The lead from the winch drum to the shipside fairlead
should be as direct as possible, preferably avoiding the use of pedestal fairleads. H pedestaJ fairleads
are used, the change in rope direction should be kept to a minimum in order to reduce the loads
on the fairlead. With limited deck space. a good arrangement can often be accomplished by placing
winches in a diagonal or transverse pattern as shown in Figs. 3.1 and 3.4, re "pecl;vely. Details of
the mooring layouts for two si7..es of ships are shown in Figs. 3.2. 3.3, 3.5 and 3.6. In these examples
all mooring lines can be issued on either side and only two pedestal fairleads arc required on the
forecastle deck 10 accomplish this (the other pedestal fairleads shown do not relate to mooring at
piers and sea islands).
Another point that must be considered is the shore lead of the li.nes issued at the extreme ends of
lhe ship. For inst81\ce, the aItermost two lines shown in Fig. 3.7, which can be issued only from
chocks located at the transom, would chafe on U\e transolO if the shore mooring dolphin is forward
of l.he transom. (This is not very common, but occasionally occurs when a large ship moors at a
berth designed for smaJler ships.) The arrangements shown in Figs. 3.1 through 3.6 provide more
flexibility in accommodating different shore moorin_s point locations.
Some arrangements incorporate a 'Hrst-ashore' line. Tbjs line is used only to assist the ship during
docking manoeuvres and is generally a polypropylene line because of its buoyancy (refer to Section
6). An 80 mm di ameter line of 370m length would be suitable for large ship". Two such line-s are
provided, one fonvard and one aft. Several con.figurations are in use to handle these lines. One is
by use of powered twin grooved drums where the line is led back and forth between the drums in a
figure-of-eight fa shion (this device ~:an be compared to a bollard with powered barrels). Tbe inboard
end of the line is taken up by a powered stowage reel, usually located below the weather deck.
Another me\'bod is to use a conventional winch. and a third method is to use a warping head of a
winch in combination with a powered take-up reel.
There is no consensus among ship operator~ as lO the need for fiTst-ashore line equipment, and no
speciaJ equipment. is shown in Figs. 3.1 through 3.6.
1f first-ashore Lines are used, they should nOl be counted in the mooring restraint requirements given
in Seciion 2 unless they are of the same material as the other mooring lines and motmled on drums
equipped with brakes as recommended in SeCliol1 7.3.2.3 Arrangements jor Spring Lines
[n order 10 provide an efficient lead to the terminal boUards, spring line issue points should be as
far forward and as far aft as possible. To avoid line chafing on the shell, the issue points must also
be within the parallel body. In practical terms, this means that the shipside fairleads serving tbe
forward headsprings should be at the point where the upper deck starts to taper into the bow area.
The shipside fairleads serving lhe aft backsprings are normally just forward of the aft accommoda-
lion house where a direct lead to the winch can be provided. This arrangement results in the aft
spring winches and the wi.nches serving the an breast lines being lOO far apart for efficient manning
during docking and undocking. To overcome this, at least o!)e owner has attempted to loca.le the
aft spring winches on the aJt deck as shown in Fig. 3.7. However, in the example shown, the ship-
side fairleads are aft of thc- parallel deck area, which ca!) result in line chafing at some terminals.
Nevertheless, Wilh proper coordin.ation of hull shape and mooring arrangement at. the early design
stage, this c.oncept may be workable and could contribute to reduced manning requ-irements.Figs. 3.1 and 3.4 show the conventional arrangement. Mooring winches sbould be placed directly in
line with the fairleads as shown. Since the ship's centreline is generally obstructed by deck piping,
main deck winches are moved to the side. In Fig. 3. L aU winches are on the port side with lhe wire
leading from the bottom of fhe drum to (he pon side and from the rop of the drum to the slar-
board side. In case of docking to st.arboard, the wire i5 led over the deck piping and over horizontal