Static Search Vs. Dynamic Search

[TorpX]

Originally Posted by gi_dan2987

I totally see the point you are trying to make. I personally think that if the target is within feasible sailing distance, and you're not nearing the point of no return on your fuel level, then making a solid dash for attack position would be well worth the extra go juice.

I personally find that galavanting around at optimal cruise speed on the surface on a search course is the best way to increase odds at running into something. While surfaced and cruising around, you're covering way more square area in a shorter amount of time than putsing around submerged with the hydrophones. Granted your watch crew may have a detection radius much smaller than your hydrophones, but the larger area you can cover on the surface more than makes up for lack of spotting radius.

Perhaps this wasn't clear from my OP, but I consider there is a BIG difference between using fuel to pursue a known contact, and using fuel to cruise around aimlessly. I think most, if not all, skippers would have used almost any amount of fuel to attack a definate target. Also, I should clearify what I mean by a 'static search'. In my example, I allowed for 20 nm movement each night. ( O'Kane mentions this as a safeguard, in case they had been spotted by an aircraft and the enemy was routing ships around their position. Maybe I'm the only one who reads O'Kane. )



Anyway, to return to my example, searching at 5 knots only increases your chances by 14%. Searching at 10 kts. gives a 49% greater chance per day. This sounds good but.... this is at the cost of reducing your time on station by a substantial margin; hence your gains are illusory.

One thing I didn't include in the OP, because I hadn't thought of it at the time. The figures if calculated are based on a searching boat moving at a right angle to the shipping lane. If the searching boat is to stay inside the lane, it must periodically reverse course and backtrack. This would have the effect of reducing somewhat the 'search bonus'. (The boat would be searching water just recently travelled through.) How much, would depend on how often it would turn around.

While surfaced and cruising around, you're covering way more square area in a shorter amount of time than putsing around submerged with the hydrophones

It is not the square area, but the radius that is important. If you can see 5 nm and you detect X % of ships transiting the area, a 10 nm visibility will allow you to detect 2X %,(not 4X %). This may seem counter-intuitive, but if you diagram it, you will see it is true.



If you want a rule-of-thumb, I would say limit your fuel use in such a way that you would be able to complete your patrol schedule. That is, for a fleetboat, be able to remain at sea for at least 60 days. I'll admit, it is more "fun" to be cruising around "doing something" than sitting still, but this is not the same as saying it is a more successful tactic.

I was thinking it would be interesting to try to pin down the math more, so different search patterns could be analyzed according to the assumptions used, but as you are the only one to post a reply, I'm guessing there is limited interest in this topic. Anyway, thanks for the response.