[magic452]

Originally Posted by TorpX

Here is a slightly different example to further illustrate the concept:

Suppose you are astride a N-S sealane and want to "search" it. I will assume, as before, freighters traveling 9 kts. and a 10 nm detection radius. (This is good for SH 4, since nothing is rendered beyond 10 nm anyway.) If you sit still you will detect 100% of ships in a 20 nm "slice" (10 nm East and 10 West). If you want to move E-W across the sealane (in effect yo-yoing back and forth), how far can you go East or West, without letting ships "slip through"? If you are cruising at 10 kts., you can go 11.1 nm on either side, and still make sure nothing gets by in the center. Why do I say 11.1 nm? Because in the time it takes you to go 11.1 nm East and 11.1 nm West (back where you started), an enemy ship could move through the 20 nm deep band you are searching. Going any farther would allow some ships to slip past. Following this plan, you will detect 100% of ships within this 22.2 nm zone, and some of the ships within a 10 nm 'fringe' zone on either side. If you wanted to cruise at 15 kts., the figures would be 33.3 nm with a 10 nm 'fringe'.

A couple of points here.

First a sea lane is not a narrow straight line even in the heavily traveled choke points. Markassar Strait is about 50 nm. wide. Luzon three times that.
Shipping lanes are no doubt about the same. You can sit in the center and still leave more than enough room for convoys to sail right by. Why give up the higher percentage for contacts just to save some fuel that is for the most part not an issue.

Second ships and convoys don't run straight courses they zig zag and can very easily sail right past you. Again a dynamic search will increase your chances of making contact and I would think the increase would be greater than what your figures suggest. The zig zags put them in your contact zone longer than a straight course would. The course changes reduce their overall progress on their base course. I do your yo-yo across the lane almost exactly as you describe but I'm also moving North or South. I described this in my second post.
Again your giving away contacts to save fuel you most probably won't need.

Third Radar. 20 nm. range Your search area doubles and enabling you to cover most of area of a choke point if you're moving.

If I'm in a dead area I'm going to patrol in a way that searches the greatest area in the shortest amount of time. Your not going to find much no matter which method you use.
Your mission is to interdict shipping not stay on station for 60 days. They have other boats to replace you in that area.

I'm wanting to RTB knowing I gave myself the best opportunity to have success.

And when I get there I'm going to say "I one of the top guns and don't send me to the Marshals again." I'm sure they will listen.

But I do see what you are saying and your points are well taken, I can see several places that a static search might be the best tactic especially early in the war where fuel is a little bit bigger concern. Armistead has pointed out a couple as well.

Magic