Geodesea_RuleofTwelths.xlsx

	B	C	D	E	F	G	H	I	J
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3		Input Predicted Tides Here
4		Tide Data	Time		Height (m)
5		LW	0:16		-0.2
6		HW	4:35		4.7
7		LW	12:18		-0.1
8		HW	16:34		4.9
9		LW	0:47		-0.2
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14		At end of period	Twelfths	In Period	Total	Time at start of period	Ht of tide at start of period	Ht of tide at end of period	Time at end of period
15	Flood 1	1	1	0.41	0.41		-0.20	0.21	0:43
16		2	2	0.82	1.23	0:43	0.21	1.03	1:26
17		3	3	1.23	2.45	1:26	1.03	2.25	2:09
18		4	3	1.23	3.68	2:09	2.25	3.48	2:52
19		5	2	0.82	4.49	2:52	3.48	4.29	3:35
20		6	1	0.41	4.90	3:35	4.29	4.70	4:18
21	Ebb 1	1	1	0.40	0.40	4:35	4.70	4.30	5:18
22		2	2	0.80	1.20	5:52	4.30	3.50	6:35
23		3	3	1.20	2.40	7:09	3.50	2.30	7:52
24		4	3	1.20	3.60	8:26	2.30	1.10	9:09
25		5	2	0.80	4.40	9:43	1.10	0.30	10:26
26		6	1	0.40	4.80	11:00	0.30	-0.10	11:43
27	Flood 2	1	1	0.42	0.42	12:18	-0.10	0.32	13:01
28		2	2	0.83	1.25	13:00	0.32	1.15	13:43
29		3	3	1.25	2.50	13:42	1.15	2.40	14:25
30		4	3	1.25	3.75	14:24	2.40	3.65	15:07
31		5	2	0.83	4.58	15:06	3.65	4.48	15:49
32		6	1	0.42	5.00	15:48	4.48	4.90	16:31
33	Ebb 1	1	1	0.43	0.43	16:34	4.90	4.48	17:17
34		2	2	0.85	1.28	17:56	4.48	3.63	18:39
35		3	3	1.28	2.55	19:18	3.63	2.35	20:01
36		4	3	1.28	3.83	20:40	2.35	1.08	21:23
37		5	2	0.85	4.68	22:02	1.08	0.23	22:45
38		6	1	0.43	5.10	23:24	0.23	-0.20	0:07
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40	This sheet is provided to help check workings when using the rule of twelfths at to find intermediate times or heights. Simply enter data in the PALE BLUE boxes
41	In some parts of the world, the rule of twelfths is worked to .01m - hence the level of accuracy.
42	The rule is used over the entire period between HW and LW. To allow this, both HW and LW times must be entered to use the sheet. If it is desired to use it over the conventional 6 hours, simply make the second time entered 6 hours later than the first.
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44	This sheet is untested. It must not be used for navigation. Use at your own risk.
45	You may freely distribute the sheet, but only in its original form please.
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