Best way to tell 150'

tis · 08-22-2006, 12:56 PM

We were told by a marine patrol officer that if you couldn't read the numbers on the boat, you were ok. I assume that is meant for 20/20 vision. Course that doesn't help from land or docks etc. Has anyone else ever been told this before?

SBC · 08-22-2006, 04:51 PM

TIS,

About 40-60% of people with 20/20 or corrected vision can read 3" high block letters (display requirement in NH) at about 125'. About 85-90% at 100'. Other factors may affect one's ability to read those numbers such as the curve of the bow, un-contrasting letters, reflection of light, etc.

So, if the bow numbers are properly displayed it should be a given that if you can read them you should be going headway speed.

BTW, these percentages are based on my own personal experience while boating with friends. There is no substitute for my first mate though. She can spot the marker buoys before I usually do and she makes a great birdwatcher too.

Sometimes I use another method learned in BSA. With a person standing 150' away I extend my arm, close one eye and match the height of a finger or thumb joint or fingernail to that of the (avg. 6') person. For me it is my thumb tip to the first joint. Sometimes I can use this method to estimate a person's (read operator, passenger) distance from me.

When in doubt, slowing down is always an option. I may have said that before....

08-22-2006, 04:51 PM	#2
SBC Senior Member Join Date: Jul 2005 Location: NH fresh waters and forests Posts: 72 Thanks: 12 Thanked 2 Times in 2 Posts	150' judgement TIS, About 40-60% of people with 20/20 or corrected vision can read 3" high block letters (display requirement in NH) at about 125'. About 85-90% at 100'. Other factors may affect one's ability to read those numbers such as the curve of the bow, un-contrasting letters, reflection of light, etc. So, if the bow numbers are properly displayed it should be a given that if you can read them you should be going headway speed. BTW, these percentages are based on my own personal experience while boating with friends. There is no substitute for my first mate though. She can spot the marker buoys before I usually do and she makes a great birdwatcher too. Sometimes I use another method learned in BSA. With a person standing 150' away I extend my arm, close one eye and match the height of a finger or thumb joint or fingernail to that of the (avg. 6') person. For me it is my thumb tip to the first joint. Sometimes I can use this method to estimate a person's (read operator, passenger) distance from me. When in doubt, slowing down is always an option. I may have said that before....

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08-22-2006, 12:56 PM	#1
tis Senior Member Join Date: Jan 2006 Posts: 6,946 Thanks: 795 Thanked 1,493 Times in 1,040 Posts	We were told by a marine patrol officer that if you couldn't read the numbers on the boat, you were ok. I assume that is meant for 20/20 vision. Course that doesn't help from land or docks etc. Has anyone else ever been told this before?