1. The point of using the nets is to bring up those creatures, specifically for their loot. The two serpent types and water elementals can have treasure maps, and the kraken can have treasure maps, Message in a bottle, and occasionally rope coils (the latter of which can be used for crafting the ropes needed to recharge an in-home hitching post). The colored ones make nice deco as well.
The white nets, from the ancient SOS, bring up special creatures. The Leviathan is the default (and shows up with a swarm of the lesser things above), and carries with it multiple chances for T-maps and SOS as well as for a mix of minor artifact and unique loot drops. The Scalis can show up if you have High Seas, and has no accompanying initial spawn (though it makes its own annoying minor spawn in the eels). It, too, has its own unique set of special loot drops (though I think some of the items are shared with Corgul). There are often additional boxes that drop on the dock when you throw a white net, that contain some of the crafting ingredients introduced with Mondain's Legacy.
2. You plot a course on a map, or take a map with the course already plotted (available on most NPC vendors that sell maps), and drop them on the pilot/rudder NPC. There are then vocal commands to have the ship attain that plotted course. However, if you aren't near the plotted start point, you might run into land, and you still have the potential of the ship stopping from hitting wildlife or other ships. However, as these maps are only Tram & Fel, they are great for fishing and trade orders, but no use for sailing in Tokuno.
3. The closest thing to that is as in #2. Take a blank map, plot your course from where you are to the rough location of the SOS. You'll still need to fine tune the end result. Of course, there are other tools that can help further. The EC, and the CC when using UOAssist, have commands that give you your coordinates without stopping to use a sextant (the latter is the command -where ). The three authorized (or at least stated, "not illegal" here by the devs) mapping programs (UOAutomap, UOCartographer, UOMapper) also have the ability to show your location graphically and by coordinates, and allow you to steer your way manually/with commandes all the way in to the coordinates without having to stop to check your position. I've also put a spreadsheet up on google sheets, for public use, that allows a person to add markers to an existing .map file for UOAM/UOCart by editing the file with notepad and pasting the copied data in (just delete each marker after you fish it up). The link can be found in the Fishing forum here.
Note also, that you only have to get within 1 degree of the SOS (about 15 movement steps - maybe more) to actually fish it up - however, note that if you have two or more SOS in close proximity, it's possible to be sitting on the location of one map, and end up fishing the more distant one up first, causing confusion.
