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Old 28-08-2016, 12:03   #106
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Re: Is all the new technology worth it?

Quote:
Originally Posted by barnakiel View Post
That math is full of holes!

There is the bow wave (that can flood any small boat) and then there is also the wind shade created by the big boat, etc.

So it is not just 50 meters that you have to cover to avoid getting hit, pooped, or sucked in. It is way more.

BTW I think cat and tri fast ferries are way wider than 50m, NO?

b.
Oh I totally agree the math is full of holes, many holes. I thought I tried to indicate something like that in a previous post.

The whole point of the math is just indicate that it doesn't take 10 or 15 minutes to get out of the way of a freighter. Of course trying to clear it by 20 seconds is ridiculous and the bow wave and other factors would probably end up swampng or sinking you anyway but even 3-45 minutes should be enough to get out of the way of a freighter and into a safe zone.

This of course does not account for fast ferries, high speed cats hydrofoils and other fast boats.
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Old 28-08-2016, 16:01   #107
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Re: Is all the new technology worth it?

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Originally Posted by skipmac View Post
Oh I totally agree the math is full of holes, many holes. I thought I tried to indicate something like that in a previous post.

The whole point of the math is just indicate that it doesn't take 10 or 15 minutes to get out of the way of a freighter. Of course trying to clear it by 20 seconds is ridiculous and the bow wave and other factors would probably end up swampng or sinking you anyway but even 3-45 minutes should be enough to get out of the way of a freighter and into a safe zone.

This of course does not account for fast ferries, high speed cats hydrofoils and other fast boats.
Your point is valid. My comments were half in jest

If one were to inadvertantly get caught in in a close crossing situation,it is useful to know the "math".

My personal opinion,& I'm probably wrong,is to reverse or alter course to avoid crossing the bow of ships if at all possible,unless I've had radio contact with same,he can see me, & he has agreed to my plans.
Too often,a large ship cannot (or will not) detect a small vessel on radar or visually. The reasons don't matter at that moment.

It is my interpretation of Rule 2b ( & natural self preservation) that I do all that is possible to avoid collision-regardless of so called "right of way".

I've had a couple of "skid mark in shorts" experiences that have reinforced my opinion

Safe travels / Len
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Old 28-08-2016, 19:07   #108
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Re: Is all the new technology worth it?

Your point is valid. My comments were half in jest

Only half?

If one were to inadvertantly get caught in in a close crossing situation,it is useful to know the "math".

Exactly. The main reason I did the math.

My personal opinion,& I'm probably wrong,is to reverse or alter course to avoid crossing the bow of ships if at all possible,unless I've had radio contact with same,he can see me, & he has agreed to my plans.
Too often,a large ship cannot (or will not) detect a small vessel on radar or visually. The reasons don't matter at that moment.

When I first started cruising I knew small boats weren't good radar targets but always assumed we were at least somewhat visible, at least a close range. Then one night in the Straights of Florida on a particularly nasty night I learned otherwise. I saw a strange configuration of lights on a vessel ahead and coming my way. The highest, brightest lights indicated a tow and as we got closer I could see red and green lights, dimmer and close to the water that had to be the barges but I couldn't decide what the bright lights in the back were. Got the guy on the radio and yes he was towing a string of barges and the lights I couldn't figure out were on another tug that was following him. I asked if he saw me and was OK with our crossing. At that point I estimated we were about three miles apart. He said yes I can running lights and gave the bearing which I confirmed but he also said he did not see me on radar.

Now it was pretty rough and he probably had the sea state filter turned up but still it was a bit disconcerting to know we were that close and I didn't show at all on his radar.


It is my interpretation of Rule 2b ( & natural self preservation) that I do all that is possible to avoid collision-regardless of so called "right of way".

That was always my plan of attack plan but recent discussion on colregs, AIS, etc made me think about this a bit. Dockhead wrote about his experience with AIS crossing the English Channel and the fact that he could see ships had altered course to increase the CPA of his sailboat many miles out and well before he could visually identify the vessels course and whether or not that vessel was on a constant bearing or not. So if Dockhead had altered course it would have thrown off the change already made by the approaching ships.

I still plan to adhere to the philosophy of get out of the way but will try to maintain my obligation to stand on, if I am in that position, until it is very clear that the other guy isn't altering and risk of collision is clear.


I've had a couple of "skid mark in shorts" experiences that have reinforced my opinion

Safe travels / Len

Haven't had to change shorts yet but had a couple of pucker factor surprises when I hadn't been paying attention for a bit too long and happened to look up and HELLO!! Where did you come from.
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Old 28-08-2016, 20:20   #109
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Re: Is all the new technology worth it?

Quote:
Originally Posted by skipmac View Post
Your point is valid. My comments were half in jest

Only half?

If one were to inadvertantly get caught in in a close crossing situation,it is useful to know the "math".

Exactly. The main reason I did the math.

My personal opinion,& I'm probably wrong,is to reverse or alter course to avoid crossing the bow of ships if at all possible,unless I've had radio contact with same,he can see me, & he has agreed to my plans.
Too often,a large ship cannot (or will not) detect a small vessel on radar or visually. The reasons don't matter at that moment.

When I first started cruising I knew small boats weren't good radar targets but always assumed we were at least somewhat visible, at least a close range. Then one night in the Straights of Florida on a particularly nasty night I learned otherwise. I saw a strange configuration of lights on a vessel ahead and coming my way. The highest, brightest lights indicated a tow and as we got closer I could see red and green lights, dimmer and close to the water that had to be the barges but I couldn't decide what the bright lights in the back were. Got the guy on the radio and yes he was towing a string of barges and the lights I couldn't figure out were on another tug that was following him. I asked if he saw me and was OK with our crossing. At that point I estimated we were about three miles apart. He said yes I can running lights and gave the bearing which I confirmed but he also said he did not see me on radar.

Now it was pretty rough and he probably had the sea state filter turned up but still it was a bit disconcerting to know we were that close and I didn't show at all on his radar.


It is my interpretation of Rule 2b ( & natural self preservation) that I do all that is possible to avoid collision-regardless of so called "right of way".

That was always my plan of attack plan but recent discussion on colregs, AIS, etc made me think about this a bit. Dockhead wrote about his experience with AIS crossing the English Channel and the fact that he could see ships had altered course to increase the CPA of his sailboat many miles out and well before he could visually identify the vessels course and whether or not that vessel was on a constant bearing or not. So if Dockhead had altered course it would have thrown off the change already made by the approaching ships.

I still plan to adhere to the philosophy of get out of the way but will try to maintain my obligation to stand on, if I am in that position, until it is very clear that the other guy isn't altering and risk of collision is clear.


I've had a couple of "skid mark in shorts" experiences that have reinforced my opinion

Safe travels / Len

Haven't had to change shorts yet but had a couple of pucker factor surprises when I hadn't been paying attention for a bit too long and happened to look up and HELLO!! Where did you come from.
OK Agreed

The other half was to not encourage those less experienced from attempting to outrun an approaching ship,especially if they are the privileged vessel -& I'm sure you weren't encouraging that.

AIS,or whatever,should be used to assess & avoid a possible close quarters situation-long before it gets to that point.

I agree fully with your stand on obligation remarks.

My years of experience as a marine electronic tech. plus some time fishing commercially -all year round in Atlantic Canada-proved to me that the best radar does well to pick up another 50ft vessel @ 4-5 nm when conditions are snotty.
Vessels are rolling 20+ deg,the weather can be clear enough to eyeball the other vessel,both vessels have metal mast,boom & other above deck structures & equipped with radar reflectors & 2 radars-hard to believe-but 4-5 nm is about all you can depend on.
So I'm not the least surprised with your tugboat encounter.

On a calm day-same radars will detect the same targets 15-20nm.

Ships are slab sided & easily detected much further.

AIS is definitely a great device. Sadly,the majority of small vessels are not equipped.
That is why I believe radar is currently more important than AIS if you travel in any conditions where visibility is limited by weather,darkness-whatever.


Len
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Old 28-08-2016, 20:39   #110
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Re: Is all the new technology worth it?

The other half was to not encourage those less experienced from attempting to outrun an approaching ship,especially if they are the privileged vessel -& I'm sure you weren't encouraging that.

Well, wasn't trying to but sometimes on the internet it's amazing how statements can be (mis)interpreted.

AIS,or whatever,should be used to assess & avoid a possible close quarters situation-long before it gets to that point.

I do confess to an aversion to last minute, white knuckle maneuvers to avoid sudden death.

I agree fully with your stand on obligation remarks.

I look forward to adding AIS and making another passage to see more exactly what's going on 8-10-12 miles out.

My years of experience as a marine electronic tech. plus some time fishing commercially -all year round in Atlantic Canada-proved to me that the best radar does well to pick up another 50ft vessel @ 4-5 nm when conditions are snotty.
Vessels are rolling 20+ deg,the weather can be clear enough to eyeball the other vessel,both vessels have metal mast,boom & other above deck structures & equipped with radar reflectors & 2 radars-hard to believe-but 4-5 nm is about all you can depend on.
So I'm not the least surprised with your tugboat encounter.

On a calm day-same radars will detect the same targets 15-20nm.

I was motoring off the coast of Central America once on a dead calm night and we could see wood dugout canoes quite clearly a few miles away. We could even see the profile and shape.

Ships are slab sided & easily detected much further.

AIS is definitely a great device. Sadly,the majority of small vessels are not equipped.
That is why I believe radar is currently more important than AIS if you travel in any conditions where visibility is limited by weather,darkness-whatever.

I have radar, plan to add AIS. Both are best but if I had only one it would have to be radar. Of course my first 2-3 years cruising my total electronics package was fathometer, VHF and autopilot and I managed to survive. Was probably just beginner's luck.
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Old 28-08-2016, 21:00   #111
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Re: Is all the new technology worth it?

I have radar, plan to add AIS. Both are best but if I had only one it would have to be radar. Of course my first 2-3 years cruising my total electronics package was fathometer, VHF and autopilot and I managed to survive. Was probably just beginner's luck.

Jeepers! You were well equipped.

I remember going lobstering with my Gramp all day in the '50s.
Wooly thick-saw nothing but the dock & some nav buoys.
All he had was a compass & a Westclox Silver Bell nailed to the dash.
Think he was part gull
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Old 28-08-2016, 21:18   #112
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Re: Is all the new technology worth it?

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Originally Posted by deblen View Post
I have radar, plan to add AIS. Both are best but if I had only one it would have to be radar. Of course my first 2-3 years cruising my total electronics package was fathometer, VHF and autopilot and I managed to survive. Was probably just beginner's luck.

Jeepers! You were well equipped.

I remember going lobstering with my Gramp all day in the '50s.
Wooly thick-saw nothing but the dock & some nav buoys.
All he had was a compass & a Westclox Silver Bell nailed to the dash.
Think he was part gull
[
ATTACH]130217[/ATTACH]
I see your grandfather was also well equipped. His clock had a minute hand.
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Old 28-08-2016, 21:29   #113
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Re: Is all the new technology worth it?

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I see your grandfather was also well equipped. His clock had a minute hand.
Aha!! That was his secret

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Old 28-08-2016, 21:38   #114
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Re: Is all the new technology worth it?

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Originally Posted by skipmac View Post
I see your grandfather was also well equipped. His clock had a minute hand.
The mind boggles as to how Slocum managed with that tin clock (sans minute hand). I'm just busy learning celestial navigation, granted the tables and methods in use today is much easier and less confusing than the ones used back in the day...

The only thing I can think of is that he must have sailed latitudes, had mad Dead Reckoning skills or possibly there's some trick to determining GMT at sunrise or sunset? Any old salts with the secret to his witchery willing to share?

From my personal experience even seconds make a huge difference, minutes would be problematic, but fractions of hours - I'm clearly too stupid to figure this out...
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Old 29-08-2016, 01:28   #115
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Re: Is all the new technology worth it?

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Originally Posted by Eben View Post
The mind boggles as to how Slocum managed with that tin clock (sans minute hand). I'm just busy learning celestial navigation, granted the tables and methods in use today is much easier and less confusing than the ones used back in the day...

The only thing I can think of is that he must have sailed latitudes, had mad Dead Reckoning skills or possibly there's some trick to determining GMT at sunrise or sunset? Any old salts with the secret to his witchery willing to share?

From my personal experience even seconds make a huge difference, minutes would be problematic, but fractions of hours - I'm clearly too stupid to figure this out...
Eben
I did some Googling Searching for Slocum's clock - Ocean Navigator - January/February 2003

Not sure if it was really missing minute hand (all the time).
Somewhat embarrassed to admit that I have never read Slocum.
Well aware of his voyage-I live in the area.

I'm old-but don't consider myself in the league of "old salts" like my forefathers or Slocum types when it comes to nav. skills.
I try to accept that "a (person) has to know his limitations"

Dead (deduced) reckoning position-relies on a "confirmed" position in the "past" & a clock/compass/speed over bottom/ tidal current/ in the interim.
Relatively easy in open ocean.
Damn difficult close to land.
Both above IMHO.






No personal experience beyond what I have read re celestial/lunar navigation.
Substantial experience in coastal navigation/cruising/fishing in foggy Gulf of Maine/Fundy/New Brunswick/Nova Scotia area.

When I read of "obtaining a sun/moon position once every 24hrs -with an accuracy of +/- one Nm"(in clear weather),it seems obvious to me,that this is useless for my inshore purposes.
Hence, the local reliance on clock(with minute hand) ,along with learned experience of tidal currents,etc. & now, thankfully,all the electronic assistance I can afford-AS A BACK-UP.(of course!

IMHO-For offshore navigation from point to distant point,celestial/lunar navigation ability would be a definite desirable skill.

IMHO. For offshore,long distance navigational purposes,to know where you are,within a mile (or several ) is "good enough" to get close to your objective.
IMHO-this is the easy part.

When you get near land,you must start using "inshore" skills/knowledge to fine tune your position.
Many thousands of fully qualified "ocean going" captains have run aground on approach to port.
There is a reason for local pilots.
There was/is? a reason for a "crows nest"lookouts,firing cannon/making noise to listen for echos,noticing "shorebirds", noticing currents,smells,etc.

Slocum was a Nova Scotian "vesseler",as was my G G father.
They earned their living "vesseling (quote my Gram),carrying goods from/to the world at the time. The same practice was common all over the world.
It was a normal "job" at the time.

How did they do it without "electronics" & "education" ?

They were well motivated-
Need to eat,feed families,earn $$-whatever.
They grew up in an age/area where a "captain" had the same elite status as a current sports/movie star/etc. has.
They WORKED their way up to captain/navigator & "Darwin" eliminated the slackers.
Land jobs were scarce.
Get away from .....etc.,etc.,

Celestial/Lunar navigation was a Required survival skill in those days.

It is still a valuable skill today if "ocean going".

IMHO
Concentrate on your "coastal" skills.
You will spend more time around "coastal" hazards.
Learn ocean navigation as required for "ocean" trips.

Again-just my opinions.

Fair winds/ Len
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Old 29-08-2016, 01:53   #116
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Re: Is all the new technology worth it?

Quote:
Originally Posted by deblen View Post
Eben
I did some Googling Searching for Slocum's clock - Ocean Navigator - January/February 2003

Not sure if it was really missing minute hand (all the time).
Somewhat embarrassed to admit that I have never read Slocum.
Well aware of his voyage-I live in the area.

I'm old-but don't consider myself in the league of "old salts" like my forefathers or Slocum types when it comes to nav. skills.
I try to accept that "a (person) has to know his limitations"

Dead (deduced) reckoning position-relies on a "confirmed" position in the "past" & a clock/compass/speed over bottom/ tidal current/ in the interim.
Relatively easy in open ocean.
Damn difficult close to land.
Both above IMHO.






No personal experience beyond what I have read re celestial/lunar navigation.
Substantial experience in coastal navigation/cruising/fishing in foggy Gulf of Maine/Fundy/New Brunswick/Nova Scotia area.

When I read of "obtaining a sun/moon position once every 24hrs -with an accuracy of +/- one Nm"(in clear weather),it seems obvious to me,that this is useless for my inshore purposes.
Hence, the local reliance on clock(with minute hand) ,along with learned experience of tidal currents,etc. & now, thankfully,all the electronic assistance I can afford-AS A BACK-UP.(of course!

IMHO-For offshore navigation from point to distant point,celestial/lunar navigation ability would be a definite desirable skill.

IMHO. For offshore,long distance navigational purposes,to know where you are,within a mile (or several ) is "good enough" to get close to your objective.
IMHO-this is the easy part.

When you get near land,you must start using "inshore" skills/knowledge to fine tune your position.
Many thousands of fully qualified "ocean going" captains have run aground on approach to port.
There is a reason for local pilots.
There was/is? a reason for a "crows nest"lookouts,firing cannon/making noise to listen for echos,noticing "shorebirds", noticing currents,smells,etc.

Slocum was a Nova Scotian "vesseler",as was my G G father.
They earned their living "vesseling (quote my Gram),carrying goods from/to the world at the time. The same practice was common all over the world.
It was a normal "job" at the time.

How did they do it without "electronics" & "education" ?

They were well motivated-
Need to eat,feed families,earn $$-whatever.
They grew up in an age/area where a "captain" had the same elite status as a current sports/movie star/etc. has.
They WORKED their way up to captain/navigator & "Darwin" eliminated the slackers.
Land jobs were scarce.
Get away from .....etc.,etc.,

Celestial/Lunar navigation was a Required survival skill in those days.

It is still a valuable skill today if "ocean going".

IMHO
Concentrate on your "coastal" skills.
You will spend more time around "coastal" hazards.
Learn ocean navigation as required for "ocean" trips.

Again-just my opinions.

Fair winds/ Len
That sheds some light on it. Also who said I'm concentrating all my efforts on celnav? Keep in mind that in our case it's practically mandatory, we only have solar to rely on for anything electrical, due to the fact that we have no inboard engine - sure we have an outboard but the alternator on it is too small to be of much use.

The older generations were not un-educated! We can all learn quite a lot from them. It pains me how my generation takes the older knowledge for granted and refuse to learn from those who's forgotten more than we've even learnt!

Cel-nav is not that hard (well the arithmetic is, but that's a different embarrassment that I have to come to terms with). It's more time consuming that using a GPS, sure!

As for not reading Slocum, it's on gutenber.org, you have no excuse - it's an awesome read, while you're at it, read Voss too! There's a lot that can be learnt from those books if you read them with the right mindset!
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Old 29-08-2016, 04:36   #117
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Re: Is all the new technology worth it?

Quote:
Originally Posted by Eben View Post
The mind boggles as to how Slocum managed with that tin clock (sans minute hand). I'm just busy learning celestial navigation, granted the tables and methods in use today is much easier and less confusing than the ones used back in the day...

The only thing I can think of is that he must have sailed latitudes, had mad Dead Reckoning skills or possibly there's some trick to determining GMT at sunrise or sunset? Any old salts with the secret to his witchery willing to share?

From my personal experience even seconds make a huge difference, minutes would be problematic, but fractions of hours - I'm clearly too stupid to figure this out...
You're right. In the standard celestial navigation seconds do count, a lot. My first trip using celestial my best "fixes" were 30 mile or larger triangles and got worse as the trip progressed. I quadruple checked my math, techniques and could find no problem. Finally figured out the stop watch I was using to set against WWV and then mark for the shots was messed up and was off by many seconds.

Slocum was using a different technique for celestial navigation called lunars that does not require knowing the exact time but does involve much more complex math. I confess I really don't know anything at all about the technique but if I recall involves using the angle hour of the moon (hence the name lunars) instead of knowing the exact time.

On my trip I ran into another shortcoming with celestial, no sky. Went for days and days with a full overcast. Finally the day my DR showed we were off the eastern Bahamas I had a clear sky just at evening twilight and managed to get a latitude from Polaris (which doesn't require accurate time fortunately) that put me right on my DR latitude. If my DR longitude was correct then that put us about 20 miles due east of Hole in the Wall light on the south tip of Andros. Sure enough, just as it got dark I could see the loom of the light flashing on the horizon. What a great feeling that was.
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Old 29-08-2016, 04:50   #118
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Re: Is all the new technology worth it?

Quote:
Originally Posted by deblen View Post
Eben
I did some Googling Searching for Slocum's clock - Ocean Navigator - January/February 2003

Not sure if it was really missing minute hand (all the time).
Somewhat embarrassed to admit that I have never read Slocum.
Well aware of his voyage-I live in the area.

I'm old-but don't consider myself in the league of "old salts" like my forefathers or Slocum types when it comes to nav. skills.
I try to accept that "a (person) has to know his limitations"

Dead (deduced) reckoning position-relies on a "confirmed" position in the "past" & a clock/compass/speed over bottom/ tidal current/ in the interim.
Relatively easy in open ocean.
Damn difficult close to land.
Both above IMHO.






No personal experience beyond what I have read re celestial/lunar navigation.
Substantial experience in coastal navigation/cruising/fishing in foggy Gulf of Maine/Fundy/New Brunswick/Nova Scotia area.

When I read of "obtaining a sun/moon position once every 24hrs -with an accuracy of +/- one Nm"(in clear weather),it seems obvious to me,that this is useless for my inshore purposes.
Hence, the local reliance on clock(with minute hand) ,along with learned experience of tidal currents,etc. & now, thankfully,all the electronic assistance I can afford-AS A BACK-UP.(of course!

IMHO-For offshore navigation from point to distant point,celestial/lunar navigation ability would be a definite desirable skill.

IMHO. For offshore,long distance navigational purposes,to know where you are,within a mile (or several ) is "good enough" to get close to your objective.
IMHO-this is the easy part.

When you get near land,you must start using "inshore" skills/knowledge to fine tune your position.
Many thousands of fully qualified "ocean going" captains have run aground on approach to port.
There is a reason for local pilots.
There was/is? a reason for a "crows nest"lookouts,firing cannon/making noise to listen for echos,noticing "shorebirds", noticing currents,smells,etc.

Slocum was a Nova Scotian "vesseler",as was my G G father.
They earned their living "vesseling (quote my Gram),carrying goods from/to the world at the time. The same practice was common all over the world.
It was a normal "job" at the time.

How did they do it without "electronics" & "education" ?

They were well motivated-
Need to eat,feed families,earn $$-whatever.
They grew up in an age/area where a "captain" had the same elite status as a current sports/movie star/etc. has.
They WORKED their way up to captain/navigator & "Darwin" eliminated the slackers.
Land jobs were scarce.
Get away from .....etc.,etc.,

Celestial/Lunar navigation was a Required survival skill in those days.

It is still a valuable skill today if "ocean going".

IMHO
Concentrate on your "coastal" skills.
You will spend more time around "coastal" hazards.
Learn ocean navigation as required for "ocean" trips.

Again-just my opinions.

Fair winds/ Len
Great post. Yes back in the day Nova Scotians were legendary sailors, like Gloucester fishermen. Wonderful heritage to have.

All very on point regarding celestial nav. When you're offshore 99.9% of the time a position within a few miles is more than adequate. If passing some offshore hazard just give it plenty of sea room. When making landfall if possible aim for a spot an easily identifiable landmark like a big lighthouse, tall headland, city, etc. Then you can use piloting skills from there. Making landfall on a low, flat, unlit coast was always the tricky one, especially at night.
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Old 29-08-2016, 05:16   #119
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Re: Is all the new technology worth it?

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You're right. In the standard celestial navigation seconds do count, a lot. My first trip using celestial my best "fixes" were 30 mile or larger triangles and got worse as the trip progressed. I quadruple checked my math, techniques and could find no problem. Finally figured out the stop watch I was using to set against WWV and then mark for the shots was messed up and was off by many seconds.

Slocum was using a different technique for celestial navigation called lunars that does not require knowing the exact time but does involve much more complex math. I confess I really don't know anything at all about the technique but if I recall involves using the angle hour of the moon (hence the name lunars) instead of knowing the exact time.

On my trip I ran into another shortcoming with celestial, no sky. Went for days and days with a full overcast. Finally the day my DR showed we were off the eastern Bahamas I had a clear sky just at evening twilight and managed to get a latitude from Polaris (which doesn't require accurate time fortunately) that put me right on my DR latitude. If my DR longitude was correct then that put us about 20 miles due east of Hole in the Wall light on the south tip of Andros. Sure enough, just as it got dark I could see the loom of the light flashing on the horizon. What a great feeling that was.
As far as I know you can only use the moon at day time!? Apparently it's too bright at night or dusk/dawn... I have no experience with this, yet...

It certainly warrants more reading...
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Old 29-08-2016, 07:11   #120
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Re: Is all the new technology worth it?

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As far as I know you can only use the moon at day time!? Apparently it's too bright at night or dusk/dawn... I have no experience with this, yet...

It certainly warrants more reading...
No, you can shoot sun or moon at anytime they are visible...sextants have filters to reduce brightness. If the conditions are right, you can shoot them both. Big objects like sun & moon are much easier to shoot than a small star from a pitching small boat.
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