262 seamanship secrets
Protection Systems and Grounding Tips
Th e best lightning protection comes from forming a cone over the boat with the
apex at the boat’s highest point. Ground the mast to the bonding point. In sailboats,
this should be the keel; in a powerboat, it might be the keel or a separate grounding
block in the bilge. Always check with the manufacturer to fi nd out if your boat is
grounded for lightning protection. Otherwise, consider running a proper grounding
wire for safety. In Stapleton’s Powerboat Bible, Sid Stapleton recommends using
#8 copper wire and cautions to run the wire in as straight a line as possible, avoiding
sharp bends. For safety, keep the bonding wire behind fi berglass liners or bulkheads.
Sailing vessels without proper grounding installations might try attaching chain,
copper wire, or battery cables to the shrouds and the backstay. Feed it over the side
and into the water to provide a ground path if lightning strikes.
How to Predict Wave Heights for Cruising
You’re preparing for that long-awaited cruise, just a short hop up the coast.
The weather forecast calls for seas running 3 to 5 feet. What does that height
range really mean, and how should you prepare for it?
THE ANATOMY OF A WAVE
Waves are created entirely by wind. Every wave has four parts: back, crest,
front (face), and trough. Know this and you can estimate the height of a wave,
measured from the bottom of the trough to the crest.
The Wave Period
If you plan on a trip outside the jetties, check the wave period fi rst. Th e wave
period is the time it takes two crests to move past a fi xed point. Th e shorter
the wave period, the less comfortable the sea is for small craft. Use a 12-second
period as a gauge for comfort. Comfort levels decrease the closer the period
gets to 0 and increase closer to 12 seconds. For example, a 4-foot sea with a
3-second period means tough going for most small craft , but a 4-foot sea with
Th e parts of a wave.