Calculating Transfer and Advance 90 degree turn

Krellian · 06-20-20, 08:14 AM

Thanks for the videos derstosstrupp! Taking notes and learning a ton.

Definitely understand using a default 35m mast it makes things quick and easy. Just refining a bit and trying to beat the disc a bit and make it do some more tricks haha. Actually helps just learning to use it better as per the video so it's been a fun exercise if nothing else.

Krellian · 06-20-20, 08:17 AM

@neistridlar 185m to complete a quadrant * 4 = circumference of 740 with radius of 117.7 no? Thus: Transfer & Advance probably 117ish?

neistridlar · 06-20-20, 05:13 PM

Yes, that sounds about right. Reading your OP back now, I think I may have misinterpreted what you meant. Combined with possibly a misspelling of 117m, turned 177m, reinforcing my interpretation.

Krellian · 06-20-20, 10:00 PM

Quote:

Originally Posted by neistridlar

Yes, that sounds about right. Reading your OP back now, I think I may have misinterpreted what you meant. Combined with possibly a misspelling of 117m, turned 177m, reinforcing my interpretation.

Oh lol sorry, I will edit that. Was drunk and typing on a half broken keyboard at 1am.

derstosstrupp · 06-20-20, 05:23 PM

Quote:

Originally Posted by Krellian

Thanks for the videos derstosstrupp! Taking notes and learning a ton.

Definitely understand using a default 35m mast it makes things quick and easy. Just refining a bit and trying to beat the disc a bit and make it do some more tricks haha. Actually helps just learning to use it better as per the video so it's been a fun exercise if nothing else.

Very happy to hear that people are getting something out of them!

Krellian · 06-20-20, 09:41 PM

Ok, so in the video where the 37 degree bearing and 3500 meter distance is calculated I think I know what to do, assuming we don't want to use a 35m mast default.

Steps

1. Immediately initiate the 90 degree turn to port after the 3500 meter distance is marked
2. We know from the current disc reading, that our distance to intercept was a little over 2100 (2106 to be precise)

3. We know (from a slide rule that I'm still looking for) that a 185 meter course turning 90 degrees at 3 knots gives us a 185 meter quadrant which, gives us a radius of 117 for that quadrant. (Would be nice to be able to calculate this using just knots and the rudder)

4. Subtract 117 from 2104 and let's just say it's 1990. (Note: we are only using the 117 Transfer. We don't need to worry about 117 advance, or the target ship's advance towards us in this time because we will do a bearing check instead and that will take care of it for us.)

5. While in the turn, set the needle at 1990.

6. Right when the turn is finished and we are on our new course, mark the bearing of the vessel used to calculate the original 3500 range. It should be about 50 degrees. The flip side of that is 40 degrees. Line up 1900 with 40 degrees. Then use the other needle to mark 50 degrees.

7. The 50 degree mark is how far that ship is from the intersection point. About 2340ish. From this we can recalculate how far that ship is from us but, we shouldn't need to now. We can just adjust speed to get 500-1000 meters from the intersect point and if we need to, calculate how fast the target will get there

Pisces · 06-22-20, 12:01 AM

Quote:

Originally Posted by Krellian

...
3. We know (from a slide rule that I'm still looking for) that a 185 meter course turning 90 degrees at 3 knots gives us a 185 meter quadrant which, gives us a radius of 117 for that quadrant. (Would be nice to be able to calculate this using just knots and the rudder)

...

I believe I have left a procedure in here somewhere to calculate the turning radius with attackdisk/sub-buddy app. No need for speed or rudder deflection, just odometer movement in the turn and the angle of the turn. And a magical mark on the time-disk representing 'degrees per radian': 57.3 seconds (on the beige scale) or 573s/ 9m33s on the white scale.

Found it: https://www.subsim.com/radioroom/sho...81&postcount=7

Krellian · 06-22-20, 05:15 AM

That's the one! Holy cow right there.

Thanks

I have the 185 marked there at the top (1850, treated as 185) with 90 degrees or (1-30) and the 9:33 minute mark points to 117 bingo.

06-20-20, 08:14 AM	#1
Krellian Swabbie Join Date: Jun 2020 Posts: 10 Downloads: 4 Uploads: 0	Thanks! Thanks for the videos derstosstrupp! Taking notes and learning a ton. Definitely understand using a default 35m mast it makes things quick and easy. Just refining a bit and trying to beat the disc a bit and make it do some more tricks haha. Actually helps just learning to use it better as per the video so it's been a fun exercise if nothing else.

06-20-20, 09:41 PM	#6
Krellian Swabbie Join Date: Jun 2020 Posts: 10 Downloads: 4 Uploads: 0	Think I got the calculation... Ok, so in the video where the 37 degree bearing and 3500 meter distance is calculated I think I know what to do, assuming we don't want to use a 35m mast default. Steps 1. Immediately initiate the 90 degree turn to port after the 3500 meter distance is marked 2. We know from the current disc reading, that our distance to intercept was a little over 2100 (2106 to be precise) 3. We know (from a slide rule that I'm still looking for) that a 185 meter course turning 90 degrees at 3 knots gives us a 185 meter quadrant which, gives us a radius of 117 for that quadrant. (Would be nice to be able to calculate this using just knots and the rudder) 4. Subtract 117 from 2104 and let's just say it's 1990. (Note: we are only using the 117 Transfer. We don't need to worry about 117 advance, or the target ship's advance towards us in this time because we will do a bearing check instead and that will take care of it for us.) 5. While in the turn, set the needle at 1990. 6. Right when the turn is finished and we are on our new course, mark the bearing of the vessel used to calculate the original 3500 range. It should be about 50 degrees. The flip side of that is 40 degrees. Line up 1900 with 40 degrees. Then use the other needle to mark 50 degrees. 7. The 50 degree mark is how far that ship is from the intersection point. About 2340ish. From this we can recalculate how far that ship is from us but, we shouldn't need to now. We can just adjust speed to get 500-1000 meters from the intersect point and if we need to, calculate how fast the target will get there Last edited by Krellian; 06-20-20 at 09:55 PM.

06-20-20, 08:17 AM	#2
Krellian Swabbie Join Date: Jun 2020 Posts: 10 Downloads: 4 Uploads: 0	@neistridlar 185m to complete a quadrant * 4 = circumference of 740 with radius of 117.7 no? Thus: Transfer & Advance probably 117ish?

06-20-20, 05:13 PM	#3
neistridlar Swabbie Join Date: Mar 2020 Location: Norway Posts: 11 Downloads: 3 Uploads: 0	Yes, that sounds about right. Reading your OP back now, I think I may have misinterpreted what you meant. Combined with possibly a misspelling of 117m, turned 177m, reinforcing my interpretation.

06-22-20, 05:15 AM	#8
Krellian Swabbie Join Date: Jun 2020 Posts: 10 Downloads: 4 Uploads: 0	That's the one! Holy cow right there. Thanks I have the 185 marked there at the top (1850, treated as 185) with 90 degrees or (1-30) and the 9:33 minute mark points to 117 bingo.