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rfreddo
08-16-2007, 09:43
Just a point of curiosity, unless I'm really missing something! The workbook problems (Chpt 5 probs 23-25 and 31) make an assumption as to planned depth that I can't figure out.

For example, in Chapter 5 problem 31, we are told that the first dive max depth was 17(56). OK, so as long as the planned depth was no greater than 60, we dived the plan. But looking at the answer in the back of the workbook, the "planned" dive was for a depth between 18(60) and 21(70). In the end it's not all that important, as long as actual max depth is within the planned range. That being said, it's curious to me why the answer uses the higher ranges. I assume this was an assumption (how's that for redundancy?), but am I missing something? Is planned depth 18(60) / 21(70) the obvios answer?

Again, it shouldn't really matter as long as max depth was less than the planned depth, but I would have (and did) answer the question by filling in the dive plan with 15(50) 18(60).

Sorry, just the A-retentiveness in me showing through.

TxHockeyGuy
08-16-2007, 10:24
Just a point of curiosity, unless I'm really missing something! The workbook problems (Chpt 5 probs 23-25 and 31) make an assumption as to planned depth that I can't figure out.

For example, in Chapter 5 problem 31, we are told that the first dive max depth was 17(56). OK, so as long as the planned depth was no greater than 60, we dived the plan. But looking at the answer in the back of the workbook, the "planned" dive was for a depth between 18(60) and 21(70). In the end it's not all that important, as long as actual max depth is within the planned range. That being said, it's curious to me why the answer uses the higher ranges. I assume this was an assumption (how's that for redundancy?), but am I missing something? Is planned depth 18(60) / 21(70) the obvios answer?

Again, it shouldn't really matter as long as max depth was less than the planned depth, but I would have (and did) answer the question by filling in the dive plan with 15(50) 18(60).

Sorry, just the A-retentiveness in me showing through.

18(60) is the planned depth. 21(70) is your contingency depth in case you blow you planned depth. When diving tables you always want to know your contingency depth and NDL (No Deco Limits), just in case you go over your planned depth and NDL.

rfreddo
08-16-2007, 11:05
Thanks. I get the purpose for the 18(60) and 21(70). Just wondering if there was any magic to picking that range for the answer or if any other range, (as long as the contingency dept was lower than 56) would have been appropriate. It seems to me the planned depth wasn't importatant to the question, as long as the contingency depth was at or below 56.

TxHockeyGuy
08-16-2007, 11:36
Thanks. I get the purpose for the 18(60) and 21(70). Just wondering if there was any magic to picking that range for the answer or if any other range, (as long as the contingency dept was lower than 56) would have been appropriate. It seems to me the planned depth wasn't importatant to the question, as long as the contingency depth was at or below 56.

Assuming the planned depth is 56 you have to use the table depth of 60 as it is the next higher. That is why you go to the next column and choose 70 as your contingency depth, your contingency depth is always the next column.