Skip to main content

Another dismasting prompts new alert

Rigging failures on passenger-carrying sailboats bring calls for scheduled rig inspections
The 60-foot charter catamaran daysailer Sebago Cubed was dismasted in the fall during a charter out of Key West with passengers aboard. Though the Coast Guard is still investigating the incident, it says the 17-year-old cat’s rotating wing mast apparently collapsed when the port wire shroud parted at a swageless terminal that serves as a common connector for both the shrouds and stays that keep the mast in place.

Note the closed turnbuckle with threaded stainless steel T-toggle screw on this Vagavbond 42's bowsprit shroud.

No one was hurt in the Oct. 30 dismasting, but it was the latest in what Coast Guard traveling inspector Marc Cruder sees as a pattern of rigging failures on commercial passenger-
carrying sailboats, catamarans in particular. What Cruder is learning about the rigging failures on these sailboats that take a daily beating should be a cautionary tale for owners of recreational sailboats, as well, he says.

On Nov. 16, the Coast Guard issued a marine safety alert (Alert 07-09) “strongly” reminding owners of commercial vessels, sailing catamarans especially, to establish their own routine inspection schedules for rigging and other systems, and not to wait for a Coast Guard inspection to catch potential problems.
“We’re trying to get everyone to be rigging-aware,” he says. “And the guys with the catamarans should be paying a little more attention than the others.”
There are just 350 inspected (commercial passenger-carrying) sailing vessels nationwide compared to about 6,000 inspected powerboats. Cruder hasn’t seen a huge number of rigging failures among sailing vessels but enough to cause concern. Over six years, 28 incidents of system failures on inspected sailing vessels have been reported, according to the Coast Guard. Of those, nine involved a failure of masts, spars or rigging leading to a dismasting. Six involved sailing catamarans. Two resulted in fatalities.

Rigging problems on passenger-carrying sailing cats appeared on the Coast Guard’s radar in late 2006 and early ’07 when two were dismasted in Hawaii, resulting in the deaths of two passengers. On Dec. 1, 2006, the mast of Na Hoku II buckled during a sightseeing tour from Waikiki Beach to Diamond Head and fell on Jordan Loser of Riverside, Calif., killing the 13-year-old boy. Investigators blamed the accident on a modification of the rig that replaced the mainsail with a modified furling jib that was attached to the mast and deck.
A few months later, on March 3, 2007, Kiele V was dismasted on a port tack during a whale-watching excursion off Ka’anapali Beach. The mast snapped off at the step and landed on 48-year-old Hal W. Pulfer II of Highland Park, Ill., killing him. Investigators found a weld failure, stress cracks and corrosion pitting at the joint where the aluminum base connects to the mast step collar.
Cruder has found some commonalities in the rig failures reported during the last six years. He says they typically involve catamarans from 60 to 65 feet and 15 to 20 years old that are licensed to carry 49 passengers. They carry an aluminum mast and stainless-steel terminals, and the mast usually is stepped on a composite fiberglass deck between the two hulls.
He says the age of a boat — and its rigging — seems to be a factor in the failures, as is the condition of the mast step and the stainless-steel terminals that secure the stays and shrouds to the mast and deck. Cruder says wires rarely fail; terminals often are the weak link. They rust and corrode.
Catamarans are more prone to failure when their rigs are not properly maintained because the cat rigs are more highly stressed than those on monohulls, Cruder says.
“When a monohull gets a gust of wind, it heels, and that reduces the load on the rig,” says Jack Mackinnon, a San Lorenzo, Calif., marine surveyor who does a lot of commercial catamaran surveys in California and Hawaii. “When a cat gets a gust of wind, it just sits there. The rig has to take that higher wind force until the boat accelerates. That’s when things get a bit gnarly.”

Some boats have fittings bolted through the deck rather than chain plates. Once the bedding of these fittings begins to leak, the bolts are subject to corrosion.

Every skipper ought to put together a rig inspection schedule and follow it, but what a particular sailboat’s schedule should be “depends on how you use it,” Cruder says. Sailing daily with passengers strains the rig more than occasional light use. Likewise, year-round sailing in Hawaii, California or Florida is much harder on a rig than sailing three months of the year in the Northeast. Sailing in places where the air is warm, salty and humid causes more corrosion of wires, stainless-steel terminals and chain plates than operating in cooler, freshwater regions.
“In the North, you have a short season. You haul the boat and take the rig off every year,” he says. The entire rig can be inspected annually. In places like Hawaii or Florida, a mast may not be unstepped for years, making it more difficult to thoroughly inspect the rig, especially the step.
“Here [in California] everybody leaves their rigs up until they fall down,” says Mackinnon. California has 115 inspected sailing vessels; Hawaii has 59. Virtually all of Hawaii’s are sailing catamarans.
After the 2006 and ’07 fatalities, the Coast Guard in Honolulu undertook a two-month “surge operation” to inspect the mast, rigging, sail area and overall condition of Hawaii’s inspected catamaran fleet. Seventy percent passed muster. Of those that didn’t, 11 had serious deficiencies that took them out of service until the deficiencies were corrected. The problems included excessive corrosion, fractures and missing bolts in the masts, spreaders and mast arms. Three vessels had too much sail area — in one case more than 200 square feet too much.
The Coast Guard in Hawaii has adopted a special inspection protocol for its inspected sailboats that includes requirements for a rig maintenance and inspection schedule, unstepping the mast every six years, and special attention to parts of the rigging more than 10 years old. Recommendations include replacing wires every six years, terminals every 12 years and chain plates every 18 years.
In California, the agency is adopting a similar inspection regimen that includes a Coast Guard-approved inspection plan for inspected sailboats and an annual rig inspection aloft by a knowledgeable crew; an inspection aloft by a rigger, surveyor or other third party every five years; and a thorough inspection of the entire rig that includes unstepping the mast every 10 years.
MacKinnon is happy to see it. “Nobody has been looking at the rigging unless they get an insurance survey,” he says. “Nobody has been going aloft.”

See related article:

- It's a problem on pleasure boats, too

This article originally appeared in the February 2010 issue.