Line cutters

I have them also,
you dont notice them when you have them.

but you know you dont have them when you pick up a lobster pot or some line get fowled in the wheels.

We have them. It's the few bucks you spend to never know if you actually needed them or if they work.

Conversely, if you don't, and foul a prop, you sit there in the blue thinking "I really should have spend the few bucks".

On goes the dive gear. May as well scrub the hull while you're down there.

Irony.

yea, i had to get in 50 degree water in Maine one time without a wet suit to cear the the prop of a lobster pot that i picked up in a crowded harbour entrance.
Sometimes, no matter how hard you try to avoid them you still pick em up.

btw the cold swim wasnt fun....

another time i had some polypro floating line all balled up on one of the wheels, the engine was vibrating and wasnt making top power, i went through hell thinking something was really bad with the engine or transmission, only to find out that there was a giant ball of that floating yellow rope around the wheel.

the cutters are now on the boat....

I have heard of a lot of situations where a vessel had a vibration problem and they suspected the line cutters being part of the problem. They would remove the gear only to find the cutters where not the problem.

I've found that the line cutters only work maybe 50% of the time if that. A lot of times the lines gets wrapped onto the shaft in front of them and they aren't effective.

Every trip I make up the coast of Washington (or down the coast of Oregon) is a game of dodge the pots. In ten years I've only picked up one. A combination of the cutter and backing down (as a precaution) completely cleared the mess and we continued our trip without a dive. My customer reports that he's picked up other lines on occasion and never had a situation where the line cutters didn't do their job.

Two enthusiastic thumbs up from me.

Wish I had cutters

Muscadine grape grows wild here in the South. Two weeks ago with the river running at flood, while moving my Roamer 125 miles upriver, I hooked a tangle on the starboard prop that rolled it into a ball. 45 minutes later with boat hook and reversing, it was mostly clear. I wish I had cutters! Tennessee River, who woulda thought?

QuicKutter line cutters

Have a look at quicKutters™ these have replaced Spurs cutters on the UK RNLI offshore lifeboats (like the US coast guard boats) and the Royal Navy, they are also used by Christensen Yachts (replacing Spurs)

The reasons have been that they are more robust and seem to have less effect on water flow. No independent trials have taken place but the overall profile is far less obtrusive to water flow.

The trouble with the simple discs as I see it is that any debris caught by a prop blade will hence be rotating with the shaft/prop/cutter disc, this means that the disc will not be slicing as the debris eventually wraps over it. True that a very sharp blade (like a razor) may slice with just pressure but I doubt any of the disc cutters would cut through rope just pulled hard across them.

You could check this theory by simply pushing a rope across the fixed blade, some tests have show what happens if the rope is held by the strut but I think it is more likely debris will be caught by th erotating blade.