[Rockin Robbins]

Well actually "constant bearing" is not a single type of attack but a family of attack methods where you aim the periscope at a chosen aiming bearing and shoot as the target crosses the wire. It differs from other attack methods because they use the position keeper to continuously update target position. Therefore the TDC is continuously changing the bearing the torpedo will follow to the target.

In constant bearing techniques the bearing the torpedo will follow or the aiming bearing is held constant and you wait for the target to cross the aiming point.

Let's say we were shooting a shotgun. You can visualize that better. One way to shoot is to sweep the gun across the sky in front of the innocent cute duckie at the correct lead angle. You can shoot any time during the sweep and hit the target. That is conventional shooting.

But another way is to visualize the right lead angle, point the gun at a spot in a sky the duck must cross. You keep the gun stationary and time the shot for when the duck is at the correct lead angle. That's a constant bearing attack. All ducks are birds but all birds are not ducks. Dick O'Kane is just one kind of constant bearing attack.

Now with a constant bearing attack we have two choices. We can arbitrarily pick an aiming bearing and let our TDC choose the lead angle, as in the Dick O'Kane and John P Cromwell methods. Or we can arbitrarily choose our impact point and calculate backward to find our proper aiming bearing, using a chart, slide rule or computer, as in the vector analysis attack or gutted's 90º attack chart. Those two choices define the differences between varied methods of constant bearing attack.

If someone is taking a specific attack method and trying to name it "constant bearing" they need to change the name of the attack. "Constant bearing" already has a precise definition and has had it for over 70 years.

Dick O'Kane, John P Cromwell, vector analysis and Fast-90 are all constant bearing attacks. The first three can be used in any submarine, the last only with a U-Boat.