If you sail in Maine, you’ve likely heard the one about the best way to cross a channel (Answer: walk across on the lobster-pot buoys). This isn’t hyperbole; visit many harbors in Maine and you’ll find them choked with pot buoys, some of them in working channels. For sailors, a wrapped prop in a tight channel flanked by rock ledges is a serious predicament: not to mention the potential damage to your engine, prop strut, or prop shaft. Thankfully, there are tools to help. The surfaces of the world’s oceans are littered with potentially harmful detritus, from fishing gear to discarded cordage to long strands of kelp, and you needn’t live in Maine to appreciate having a good cutter on your prop.
These cutters come in two basic flavors: There are disc-type cutters that attach to your prop shaft and have sharp edges (some of which are serrated) on their outer circumference. Then there are scissor-type systems that cut lines by forcing them between two sharp edges, one mounted on the hull, skeg, or shaft strut, the other on the prop shaft itself.
Disc-type cutters are typically attached to the shaft forward of the propeller. Theoretically, the disc’s razor-sharp edge will slice through any wrapped cordage. This immediately conjures up thoughts of drag, but according to AB Marine’s Steve Armitage, “You’re exposing maybe a half inch more area than the prop hub. The average cruising sailor will never notice it. It’s like towing a fishing lure, not a bucket. It’s minimal.” Disc-type cutters are available for both conventional propshafts and saildrives.
With two-part systems, such as Spurs Marine’s “Spurs”, one (or more) cutting parts (think of them as rugged double-sided razor blades) are mounted on the shaft immediately ahead of the propeller. A second sharp blade is permanently attached to the strut (clamp-on versions are available for boats with thin-walled struts). When the prop ingests a line, the spinning action forces the line between the two sharp edges, where it meets the scissor-like cutting action of the blades. These units are available only for inboard engines with a shaft.
Only a tiny percentage of customers cite lobster-pot tackle as the reason for adding this units to their boats. “Everybody is vulnerable, both sailors and power boaters,” reports Spurs Marine’s Don Govan. “We sell our gear to customers all over the world, including commercial fishermen.” According to Govan, Spurs Marine sells its cutters to five different Coast Guards (including the U.S. Coast Guard), as well as the U.S. Navy.
Having personally wrapped everything from spinnaker sheets to fishing line to lobster pots around propellers over the years, I can attest it’s no fun taking a “mandatory” swim in sometimes-frigid water. But safety concerns about potentially losing power and steerage in a dicy channel are better grounds for seriously considering a cutter. “As far as safety, [these cutters] protect your drive train system. There are people who have bent and damaged their prop shafts,” says Armitage. “This gear can—and does—avoid damage, and it keeps you from having to go for a swim.”