Editing Propeller (section)

===Weed hatches and rope cutters===
[[File:Right-handed 3-blade bronze propeller & stainless steel rope cutter.jpg|thumb|Bronze propeller & stainless steel rope cutter]]
Whereas the propeller on a large ship will be immersed in deep water and free of obstacles and [[flotsam]], [[yacht]]s, [[barge]]s and [[Launch (boat)|river boats]] often suffer propeller fouling by debris such as weed, ropes, cables, nets and plastics. British [[narrowboat]]s invariably have a '''weed hatch''' over the propeller, and once the narrowboat is stationary, the hatch may be opened to give access to the propeller, enabling debris to be cleared. Yachts and river boats rarely have weed hatches; instead they may fit a '''rope cutter''' that fits around the prop shaft and rotates with the propeller. These cutters clear the debris and obviate the need for divers to attend manually to the fouling. Several forms of rope cutters are available:<ref>{{Citation | title = Yachting World rope cutter test | date = 14 April 2015 | publisher = Yachting monthly | url = https://www.yachtingmonthly.com/gear/propeller-rope-cutter-test-30012}}</ref>
#A simple sharp edged disc that cuts like a razor;<ref>{{Citation | title = Simple disc cutters | publisher = ASAP Supplies | url = https://www.asap-supplies.com/propeller-drivetrain/rope-cutters}}</ref>
#A rotor with two or more projecting blades that slice against a fixed blade, cutting with a scissor action;<ref>{{Citation | title = Spurs scissor-action rope cutter | publisher = Spurs marine | url =  https://www.spursmarine.com/shaft-cutters/}}</ref><ref>{{Citation | title = Stripper scissor-action rope cutter | work = Rope stripper | url  = http://ropestripper.com/strippers.php}}</ref><ref>{{Citation | title = Gator cissor-action rope cutter | work = Prop protect | url = http://www.propprotect.com/}}</ref>
#A serrated rotor with a complex cutting edge made up of sharp edges and projections.<ref>{{Citation | title = Images of rope cutters | work = Bing | publisher = Microsoft | type = search | url = https://www.bing.com/images/search?q=yacht+rope+cutter&id=9A2642834983B967EF5261F4A95842DA499E0528&form=IQFRBA&first=1&scenario=ImageBasicHover}}</ref>