Page 52 - The Complete Rigger’s Apprentice

BLOCK CONSTRUCTION variety of hardware that today’s sailor has to choose
from. What follows is information about the details
Blocks, those ancient, indispensable sail-control of blocks, old and new, to help you pick the gear
tools, have been high-tech’d. For so many years they that best suits you and your boat.
were simple, stolid assemblies of wood, bronze, and
steel. But nowadays they’re likely to evidence Spiel- The Body of the Block
bergian gee-whiz design and obsessively close-toler- There are two components to every block: the body,
ance engineering of multisyllabic plastics. or shell, and the sheave. It is helpful to consider
And more has changed besides materials and these separately.
appearance; old-time blocks were mostly variations The body is a combination of sheave housing,
on a simple theme, but modern ones are specialized load bearer, and rope protector. In a traditional
as to function, load, and (often novel) rig detail. On block, all of the load is borne by a metal strap that
a typical production boat today you’ll find standup runs down the inside of the block, on either side of
blocks, two-line turning blocks, ratchet-sheave the sheave. Wooden “cheeks,” there to protect the
blocks, flip-flop (I am not making this up) blocks, rope, are set outside this strap, and are fastened
over-the-top blocks, etc. And old-style blocks, together with spacers, called “swallows,” in between.
adapted and updated, are still very much in the pic- Modern blocks are aluminum- or steel-cheeked
ture. Far from being outdated, they add to the rich to save weight and bulk. On some models the cheeks
are the weight-bearing structure, but that job might
Figure 2-12. Examples of two modern blocks. Blocks also be done, as with traditional blocks, by a metal
like the air block (left). Here a piece of bungy cord has strap (Figure 2-13). The strap is preferably of type
been threaded through the hole where the axle used to 316 stainless steel, a particularly corrosion-resistant
be. The block can now be suspended from an adjacent alloy. Bronze straps are also excellent, since they are
lower lifeline, so it won’t bang on the deck. On other both corrosion- and fatigue-resistant, but many sail-
airblocks, this space can be used as the deadend of ors just like the look of shiny steel.
a purchase system. A Harken “flip-flop” block (right) When choosing between wood and metal
is another recent development in block design. The bodies, the first consideration for many sailors is
line enters the block through the hollow axle, turns on weight—will the cumulative mass of a lot of blocks
the sheave, and exits at the cam cleat. The block can make the boat top-heavy, compromising sailing effi-
pivot, so can be tended from either side. The cam can ciency? I used to think that this was only an issue
also be adjusted for lead. (Margaret Wilson-Briggs) for very high-performance boats. And while light
rigs are more significant for racers than for cruis-
ers, it is generally a good idea, on any sailing vessel,
to reduce weight aloft. It is possible to go too far,
reducing the roll moment to the point where every
little wavelet and puff of wind makes the boat lurch.
The motion resulting from an underweight rig, espe-
cially when exacerbated by a stiff modern hull, is
hard on the crew, and shortens rig life, too. But you
have to take a lot of weight out of a rig to get that
kind of unfortunate result. It is far more common
to find that the rig is overweight; doing what you
can to reduce weight aloft will help the boat sail
upright, so crew comfort is improved, helm balance
improved, and reefing frequency reduce. So, to get

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