- lnslaffarionlmalerial. As mentioned in Seclion 5, the type of frame cOIL~tmction can seriously
affect the ease of installalioll. Designs with a closed base member effectively connecting the
end posts are preferable. Also if the frame Ls made of steel of higher slrength than the ad-
joining hull struclllre. elaborale hull reinforce.ments will be required.
Four-roller and (ivc -rollcr Iyp e (airle d. a re covered by JIS F202fl. but [he stn::D.,th i-n t ' iven ~IIlU
the listed 'applicable wire rope diameler' is considered large in relation to the roller diameter. The
largest, having rollers of 315mm diameter, would be suitable for wire ropes (with r\lRe) up [0
32mm in diameter. This size would not be suitable for instance for VLCCs. Also. the 1IS base is
nOl the preferred type (see Section 5).
All rollers should have lubrication-free bearings (but with grease rupples fitted) and provisions for
tuming with a hook spanner.
8.7 EYEPLATES
Eyeplates are used in the manifold area for securing boses (see Section 9) and have various other
applications aboard ships. The British Standard BS MA 10 shows suitable eyeplates and includes
safe working loads at any angle of pull.
8.8 STOPPERS
The most common loose filling is a stopper, which is required to temporarily bold the load of a
line while the line is in the process of being belayed on a bollard.
Common methods of stopping-off wire or YJllhetic and natura] fibre ropes are shown in Fig. 8.5.Stopping off a line is a dangerous operation. High loads in the line mu~l be avoided. since (he
stoppers have less strength than the mooring line. Only a properly sized 'carpenter's' stopper can
approach the line's strength.Standard fibre stoppers for fibre ropes, as well as chain stoppers for wire ropes, are covered by the
BSRA Shipbuilding Standard No. SIS 23. Three different sizes are listed for each type, including all
details and rhe SWL. The fibre stoppers are of three-strand polyester rope and may be used on any
synthetic or natural fibre mooring rope.8.9 SELECTION OF FITTING TYPE
At the ship design stage, a decision must be taken regarding the types of fairleads employed at the
shipside for use with mooring lines. Roller-type chocks resuJt in less line wear and improve the
wincb hauling capacity because they reduce friction between line and chock. On t.he other hand,
roller-rype fillings require more maintenance and can be very large if the rollers are of proper size
for the intended service. A large bend radius is much easier to realise ju Panama-type fairleads and
for [his reason they are often used in combination with winch-mounted wire ropes.Winch-mounted fibre lines should ideally be used with roller-type fajrleads, since Ihe friction created
by tbe fL'(ed fairleads can Jead to rapid line damage. However, the cnrrent ,practice of operating with
reduced crewing has resulted in closed fairleads being preferred for all rope types, mainly due to the
higher maintenance associaled with roller fairkads.Secondary mooring lines associmed with bollards (lines nm required to meet tbe mooring restraint
reQuirement lisled in Section 2) and tug lines are usually served by fixed fairleads.