PS Advior 05/01/98
I enjoyed your December 1997 article on replacing wire halyards with all rope. When I considered it a few years ago, my rigger told me that going from wire with rope tails to all-rope would require changing the halyard block and sheaves, and recommended against it. You seemed to imply it was a piece of cake. How difficult is it, and what’s involved?
Alan Zimmerman, MD
Lido Beach, California
The masthead sheaves definitely are a consideration in making the conversion from wire/rope to all-rope halyards. At issue is whether the new rope will properly seat in the sheave. Sheaves for wire and rope usually have for the wire a narrow groove at the bottom of the larger rope groove. They are, therefore, doing double duty, accommodating both wire and rope. Unless your new rope is of a larger diameter than the old rope tail, it should seat satisfactorily in the old sheave. With modern low-stretch rope, it is possible to have very strong, low-stretch halyards with a relatively small diameter. When we removed the sheaves on Viva (aluminum with Oilite bearings), we found that much of the wire groove had over the years been worn away by the rope. Instead of replacing the sheaves, we polished them on a wheel and reinstalled them. We are aware that rough spots in the wire groove could cause premature wear on our new halyards, so we are keeping an eye on them for signs of chafe.
Sparmakers use different methods of installing sheaves but in most cases removing the sheaves should not be that difficult. Generally, a large diameter pin is run through the mast and spacers (to keep multiple sheaves apart) and secured by some sort of end cap on the outsides of the mast. The biggest problem we had was removing the stainless screws in the end caps, as they had initiated some corrosion with the aluminum mast. Liberal application of a thread loosener such as WD-40 and patient use of a screw driver, possibly with Vice-Grips, should get them out. If not, try heating the screw with a butane torch. If it shears off, then you must use a screw extractor, which can get tedious, and will require tapping a larger diameter hole for the replacement screw.
New sheaves are available from many hardware manufactures such as Harken and Ronstan. Overall diameter, width, pin diameter and the maximum rope size it can accommodate are the key dimensions. Unless you opt for a ball bearing model, they are not very expensive.
Fighting the Damp
We go cruising on our vacation time on Lake Superior. With each passing day, the boat slowly gets damper and damper. Is there any way to avoid having vapor condense to liquid overnight on the inside of the boat?
Enclose people exuding warm, moist air in a warm boat on a warm evening, drop the temperature sharply and, when you hit the dew point, you get condensation. We’ve always viewed those millions of tiny droplets as an opportunity to wipe down the interior with a clean towel.
You can preclude it from happening with ventilation, but the cold outside air is not always welcome. Solar/battery-powered vents help to keep the air circulating and will also cut down on mildew forming everywhere. We’ve also seen temperature drops so severe (as when a cold squall line rips into a sweltering evening) that no amount of ventilation would keep up with it.
If you use them, sleeping bags (even the modern ones made of synthetic materials) can accumulate, hold and release at the wrong time a lot of moisture. Sunning them helps dry out the boat.
A superior and more expensive measure is to line the interior of the boat with an insulating material, such as foam-backed fabric. We’ve found that shops doing van conversions are a good, local place to shop for such fabrics. They can be applied with contact cement to the sides of the hull and even the overhead, though fitting gets trickier up above. Balsa- and foam-cored boats don’t tend to condense moisture as much as solid fiberglass hulls.
A similar letter from Gordon Allison, who sails on Lake Grandby, Colorado, was published January 15, 1997, and prompted a number of suggestions from other readers. We noted then that Defender Industries (800/628-8225) sells a Vinyl Foam Bulkhead & Ceiling Lining that may work. It sells for $14.95 a yard. Also available from Defender is Nautolex White Headliner Material in 54" widths that sells for $8.95 per yard.
Ideas from readers included better insulation of your body (quality sleeping bag, long underwear, etc.) and rigging an awning low over the deck so the relatively warm surface of the deck doesn’t “see” the dark sky “to which it would otherwise radiate large amounts of heat.”