[joegrundman]

Optimal Approach Course

that was the Normal Approach Course

however, since we are not attempting to ram the target, we don't need to optimise our interception chances for colliding with the target itself.

we are interested in the best chance of getting into a torpedo attack position, which let us say is about 800 yards off the target beam.

therefore to find the approach course that absolutely maximises our chances against a faster, unknown target, we need our normal approach course not to be relative to the target, but relative to a 'virtual' target that is 800 yards nearer to us, and exactly on the target's beam.

This is not possible to solve exactly without other information, but will account to an offset of a few degrees forward of 90. E.g an intercept bearing to target of around 85 degrees will marginally improve your chances over a bearing of 90.

This is the Optimal Approach Course.

Note: having established this course, and you are pulling ahead of the target, you may of course narrow the bearing to target in order to speed up the intercept, or you may slow down in order to save batteries.

but if it is pulling ahead, you can only speed up if you are already on the optimal approach course.

It is therefore sound practice to begin the approach at the highest speed that is practical - you may slow down if it's possible, but if you start slower, you may have lost your opportunity to hit a target without surfacing.