Originally Posted by seafrontiersman
I go to sea for a living and I can tell you that on commercial vessels, Rule 5 (as interpreted by USCG, insurance carriers, and various international governing bodies) DOES require a constant visual lookout by a person who is not actually steering the vessel. This is heavily referenced in the STCW course "bridge resource management" not trying to be pedantic, just stating the facts...
As a single/short handed sailor, I also realize that this is simply not practical on all vessels at all times.
It absolutely should require a constant visual lookout for commercial vessels. Given the manning available there is no excuse for less.
The impracticality of the same interpretation for a single/short-handed sailor does not mean said sailor is in violation of the rule but is unable to reasonably comply ... it simply means that the interpretation of the rule is dependent on the specific situation (which is exactly why the rule includes so many qualifiers...). But ... a debate on the semantics of the rule is tiresome and irrelevant to my original point ... what matters with regard to Rule 5 for the sailing situation I'm discussing (single/short-handed sailing) is the spirit of the rule, minimizing risk of collision with the available resources.
The 'look interval' I refer to has two implications. First, it lets you know how long you can go between visual sweeps. Second, it lets you know how long you can't
go between visual sweeps.
Some have chimed in and claimed 20 minutes as the correct interval. Someone else said 10 minutes. I ask you, why 20? Why not 30? Why is 10 safe? Why isn't anything longer than 5 minutes putting yourself at risk? If you don't have reason to support a specific number ... then your specific number is just arbitrary. Some even claim that the safe way for a single-handed sailor to accomplish sleep on a passage is to heave to.
If this fancy super-freighter moving along at 40kts is coming towards you then it will cover 13 nautical miles within a 20 minute interval. If you are cruising along at 7.5kts then you will close another 2.5 nautical miles and you'd better hope you can see that contact further than 15.5 nautical miles away.
So ... we make the interval 10 minutes ... and we are still single handed. You try to maintain lookouts every 10 minutes but ... damn it, you're a human being ... and instead, after maintaining this ridiculous schedule for 3 days, you fall hard asleep for 2 hours. You're at risk of collision from anything on the water if you pass out for two hours.
You heave to, cut your own forward progress to 0.5kts, and go below to sleep for 2 hours. You're still at risk for collision from anything on the water. 2 hours is enough time for a 12kt freighter to cover 24 nautical miles and I promise you that you won't see a freighter from 24 nautical miles away before you tuck yourself in. The fact that you cut your own ground speed to almost nothing has very little effect on your safety from collision.
These are all situations of how long you can't
take your eyes off the horizon.
You've been standing watch continually for the past 8 hours, you're in the tropics, sailing in 8 kts of breeze downwind, and if you don't get below for a cold beverage and a few minutes in front of the fan in the shade then you're seriously considering heat stress. How long can
you take your eyes off the horizon?
You thought you were going to be standing port/starboard with your other shipmate. Unfortunately, 400 miles off the coast they decide to eat the wrong thing and now they are lying in the fetal position on the cabin berth. Now ... you're single handed. You're getting pissed that they can't even get up long enough to fix you a meal ... and now you're starting to feel sick to your stomach. How long can you afford to hit the head?
If you head down for 20 minutes should you be filled with paranoia and punish yourself for being such a shoddy seaman? Maybe, maybe not ... it depends on how long you can take your eyes off the horizon and there is a reasonable way to determine that.
A short-handed sailor needs to be able to make compromises. Compromises based only on superstition or guesses aren't very confidence inspiring and may/may not be wise compromises to make. A look interval is a tool. If you don't want to use it, what do I care? Keep coming topside every 10 minutes. 10 minutes is probably sufficient for safety (probably entirely impractical single handing) and maybe 10 minutes, given the conditions, is even often enough to keep you safe. Wouldn't you like to know that? I guess not.