"RogueIT" wrote in message
oups.com...
So I can tie a bowline and a figure 8 but I am not sure what their
primary
uses are on a boat.

1. can anyone tell me what they are used for?

Bowline: non-tightening loop at the end of a line. Myriad uses, such as
affixing anchor rodes to shackles--either end, halyards to headboard or to
halyard shackles, sheets to jib clew, tack downhaul line, reefing lines,
flag halyards, securing halyard to bosun's chair, etc. Very secure and
easily removed.

Figure 8 is used as a line stopper. Won't allow the line to pass through a
fairlead or sheet stopper, but is easily removed as it won't tighten upon
itself like an overhand knot.

2. what other knots should I know and why are these knots used?

Clove hitch--for fastening a dockline to a dock piling or rail.
Half-hitches--see clove hitch.

Those four knots will accomplish 90% of everything you need to do with a
line.

Also learn how to do a proper flemish on a cleat.

Max