Ratchet blocks allow hand holding loaded sheets. The
eight-sided faceted sheave
grips loaded sheets yet allows a line to be eased instantly with control. They allow the
crew to hand hold main, jib, and spinnaker sheets with only a faction of the effort that
a regular block requires.
Holding power varies according to sheave size and type.
57 mm Ratchamatic blocks with eight-sided faceted sheaves can provide up to
10:1 holding power.
57 mm Power3 Ratchamatic blocks with added facets offer increased holding
power. See chart below.
75 mm Ratchamatic blocks with eight-sided faceted sheaves can provide up to
15:1 holding power.
Holding power ratios are determined using a 180° wrap angle and can very according to line
type, and line condition
.
Using Ratchet Blocks
Power3 Ratchet Blocks - Holding Power
Power3 57 mm ratchet blocks offer three options of faceted holding power to best take advantage of
the day’s wind and wave conditions.
Ratchet Direction
Arrow on side of block shows direction that sheave
will spin when ratchet is switched on. Refer to arrow
when reeving block or mounting cheek block.
57/ 75 mm block no
.
Sheave color Holding power 57 / 75 * Sheave image and facet count**
2135 - 57 mm
2670 - 75 mm
Black
10:1
15:1
Example: Block holds 45 kg (100 lb) load with 4.5 kg (10 lb) of effort
2166 - 57 mm
2174 - 75 mm
Titanium
(tan)
15:1
22:1
Example: Block holds 67.5 kg (150 lb) load with 4.5 kg (10 lb) of effort
2169 - 57 mm
2176 - 75 mm
Silver
20:1
30:1
Example: Block holds 90 kg (200 lb) load with 4.5 kg (10 lb) of effort.
8 facets
60 facets
45 facets
Switches
An on/off switch allows the ratchet to be turned off in light air
to trim and ease lines more easily.
The 2608, 2609 and 2614 have on/off switches; other 40 mm
ratchet blocks are always in ratchet mode. All 57 and 75 mm
ratchet blocks have on/off switches.
*Holding power ratios are determined using a 180° wrap angle and can very according to line type, and line
condition. Depending on line composition and cover texture, the more aggressive sheave facets can increase
line wear.
**The 2170 block sheave has fewer facets than the 2167 and gains more holding power by having more
prominent ridges.
Switch Operation