When sailing offshore we keep a 24h watch but sometimes we're not in the cockpit all the time. My trusty eggclock is ticking at 10-15 minutes if i need to do something down below or just want to sit down during those long night watches.
In the channel between St Lucia and Martinique we had a close encounter with an other sailingyatch crossing our path. He had no lights, no visible watch in the cockpit and didn't reply on VHF.
I spotted him/her/it as the lights on a cruise ship a couple of M away started to disapear strangely and in my binoculars i could se the outlines of a main and a headsail. Since I was following a couple of commercial ships on radar it was not in tune to spot smaller wessels. After calling him on VHF with no reply I spilled wind out of my sails and let him pass 100m infront of us while studying him. I could not se any lights nor anyone in the cockpit or below (what I could see).
My conclusions were that he was comming from an atlanticcrossing, sleeping during the night and just by luck missed the two islands and all the ships between them. He was sailing a pararel course to us doing the islandhopping.
I usually have a hard time deciding how to do with my radar, should it be on a high scale tracking bigthings far away or small tings close? If I tune it to spot sailingyatchs at below 40' it will be hard spotting the big ships at a safe distance with it. Sure one can spot the big ones opticaly but sometimes weather stop that too.
My thoughts on commercial wessels seing cruicers, my opinion is that they don't and it's my resposibility to keep away from them. I've often called up ships on VHF with no respons, but now with AIS and DSC it may be easier then before I hope, calling a ship by position, speed and course should be enough to get someones atention in my opinion but if the watch is occupied playing doom on the computer he might miss it.