Worksheet 21 · Skill 8
Light rising
Plot Pass worksheet. Plot Pass $1.95/month or $19.50/year · Free during preview. Plotroom · cedarpointmarina.net · invented chart, not for navigation.
On a clear night your height of eye is 6 ft. You are closing a light listed as 80 ft high, nominal range 5 nm.
Find its geographic range (how far off its light first clears the horizon for you) and the distance at which you should first see it. Take the nominal range as its luminous range on this clear night.
Use the horizon distance d = 1.17 × √h (nm, h in feet). Tolerance: 0.15 nm.
Geographic range: ________ nm First seen at: ________ nm
On a clear night your height of eye is 9 ft. You are closing a light listed as 30 ft high, nominal range 7 nm.
Find its geographic range (how far off its light first clears the horizon for you) and the distance at which you should first see it. Take the nominal range as its luminous range on this clear night.
Use the horizon distance d = 1.17 × √h (nm, h in feet). Tolerance: 0.15 nm.
Geographic range: ________ nm First seen at: ________ nm
On a clear night your height of eye is 20 ft. You are closing a light listed as 100 ft high, nominal range 11 nm.
Find its geographic range (how far off its light first clears the horizon for you) and the distance at which you should first see it. Take the nominal range as its luminous range on this clear night.
Use the horizon distance d = 1.17 × √h (nm, h in feet). Tolerance: 0.15 nm.
Geographic range: ________ nm First seen at: ________ nm
On a clear night your height of eye is 23 ft. You are closing a light listed as 100 ft high, nominal range 10 nm.
Find its geographic range (how far off its light first clears the horizon for you) and the distance at which you should first see it. Take the nominal range as its luminous range on this clear night.
Use the horizon distance d = 1.17 × √h (nm, h in feet). Tolerance: 0.15 nm.
Geographic range: ________ nm First seen at: ________ nm
On a clear night your height of eye is 13 ft. You are closing a light listed as 75 ft high, nominal range 18 nm.
Find its geographic range (how far off its light first clears the horizon for you) and the distance at which you should first see it. Take the nominal range as its luminous range on this clear night.
Use the horizon distance d = 1.17 × √h (nm, h in feet). Tolerance: 0.15 nm.
Geographic range: ________ nm First seen at: ________ nm
On a clear night your height of eye is 17 ft. You are closing a light listed as 70 ft high, nominal range 5 nm.
Find its geographic range (how far off its light first clears the horizon for you) and the distance at which you should first see it. Take the nominal range as its luminous range on this clear night.
Use the horizon distance d = 1.17 × √h (nm, h in feet). Tolerance: 0.15 nm.
Geographic range: ________ nm First seen at: ________ nm
On a clear night your height of eye is 12 ft. You are closing a light listed as 155 ft high, nominal range 20 nm.
Find its geographic range (how far off its light first clears the horizon for you) and the distance at which you should first see it. Take the nominal range as its luminous range on this clear night.
Use the horizon distance d = 1.17 × √h (nm, h in feet). Tolerance: 0.15 nm.
Geographic range: ________ nm First seen at: ________ nm
On a clear night your height of eye is 9 ft. You are closing a light listed as 140 ft high, nominal range 8 nm.
Find its geographic range (how far off its light first clears the horizon for you) and the distance at which you should first see it. Take the nominal range as its luminous range on this clear night.
Use the horizon distance d = 1.17 × √h (nm, h in feet). Tolerance: 0.15 nm.
Geographic range: ________ nm First seen at: ________ nm
Answer key
| No. | Answers | Problem |
|---|---|---|
| 1 | Geographic range: 13.3 nm First seen at: 5.0 nm | No. 21001 (worked solution) |
| 2 | Geographic range: 9.9 nm First seen at: 7.0 nm | No. 21002 (worked solution) |
| 3 | Geographic range: 16.9 nm First seen at: 11.0 nm | No. 21003 (worked solution) |
| 4 | Geographic range: 17.3 nm First seen at: 10.0 nm | No. 21004 (worked solution) |
| 5 | Geographic range: 14.4 nm First seen at: 14.4 nm | No. 21005 (worked solution) |
| 6 | Geographic range: 14.6 nm First seen at: 5.0 nm | No. 21006 (worked solution) |
| 7 | Geographic range: 18.6 nm First seen at: 18.6 nm | No. 21007 (worked solution) |
| 8 | Geographic range: 17.4 nm First seen at: 8.0 nm | No. 21008 (worked solution) |