Bubblehead1980 |
06-04-13 12:39 PM |
Speed can be entered anytime, if you dont know target speed, estimate and enter into TDC so TDC can have a solution, then refine it.Remember to activate the position keeper(PK) so the data is updated automatically(based on what you entered).
Easy way to obtain speed...start the stop watch, mark x on location of the target on map(relatively easy if using map contacts, if not, takes a bit more guess work but is possible) then time it for 3 minutes, mark position after 3 minutes.Then using the ruler draw a line from the first x to the second x, measure the distance and can obtain speed.Say a target moved 900 yards, his speed is 9 knots.Pretty simply.For quicker solutions that requires on the fly shooting, measure targets travel distance for one minute, say he moved 300 yards, you got it, his speed is 9 knots, unless he changes etc but its not the usual unless hes been alerted or has a pre planned course change.
Rule of thumb to remember is that 1-7 knots is "slow" 8-12 is"medium" and 13-20 is "fast" , anything over 20 is "Very fast" so this can help estimate if you sonar operator says this or you see a contact report, map contact etc that says this.
There are various "fancy" shooting solutions you can learn but I prefer the historically accurate methods.One is the old way, get a final periscope bearing, fire 10 seconds apart, use the spread knob to send fish to different points along target.I prefer the other that many of the top skippers used such as O Kane, which was to aim each torpedo as an individual shot.Example, you have a large freighter ahead, typically worth 3 torpedoes, maybe 4 but 3 for this purpose.Ill aim one at middle of target, just in front of the stack if its admidships, then move scope crosshairs over forward mast, send new bearing to TDC, fire two, then move cross hairs just in front of rear mast, send to TDC, fire three.This is simple and accurate, just make sure you have speed and AOB.
I typically enter range, bearing estimate, then AOB and speed estimate, then enter into TDC, then after measuring speed, I enter it, if AOB wasnt too far off and PK is on, itll updated it accurately based off of the original AOB.
Hope this helped.
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