Is all the new technology worth it?

[StuM]

Originally Posted by skipmac

Hi Len,

No argument at all with your first point.

Regarding the math yes I've done it. 20 knots works.out to 121,520 feet per hour or approximately 34 feet per second. 6 knots works out to about 10 feet per second. Assume a medium-sized freighter has a beam of 200 feet.

For simplicity's sake ignoring the length of the sailboat it would take about 20 seconds to go 200 feet. In those same 20 seconds the freighter would go approximately 700 feet. So based on that math if a freighter was 1000 feet away and you were totally insane you could probably cross in front of it and make it in one piece.

It's so much easier in metric

A large container ship has a beam of about 50 m.
Assume 10m sailboat and 10m either side to clear the bow wave, so distance required to cross = 80m
6 knots = 3m/s. Time required = 80/3 or about 27 sec
20 knots = 10m/s. Distance traveled by freighter = 27x 10 = 270 meters.

[deblen]

Originally Posted by deblen

You have obviously never sailed in Maine fog surrounded by Maine lobster boats
Good luck with "right of way",AIS,chartplotter,horns,bow watch,etc. & NO Radar.
Len

The fog of which I speak

[deblen]

Originally Posted by StuM

It's so much easier in metric

A large container ship has a beam of about 50 m.
Assume 10m sailboat and 10m either side to clear the bow wave, so distance required to cross = 80m
6 knots = 3m/s. Time required = 80/3 or about 27 sec
20 knots = 10m/s. Distance traveled by freighter = 27x 10 = 270 meters.

Yes-it is easier in metric.
Make sure you are wearing metric underwear / L

Ferry bow.jpg Views: 122 Size: 90.5 KB ID: 130140" style="margin: 2px" />

[StuM]

Originally Posted by deblen

Yes-it is easier in metric.
Make sure you are wearing metric underwear / L

Attachment 130140

I'd need at least 10 litre capacity underwear if I ever saw that bearing down on me

[skipmac]

Originally Posted by StuM

It's so much easier in metric

A large container ship has a beam of about 50 m.
Assume 10m sailboat and 10m either side to clear the bow wave, so distance required to cross = 80m
6 knots = 3m/s. Time required = 80/3 or about 27 sec
20 knots = 10m/s. Distance traveled by freighter = 27x 10 = 270 meters.

Of course it's easier in metric.

The most difficult part of metric...................................

trying to teach it to Americans.

[skipmac]

Originally Posted by deblen

Yep. Assuming one is totally insane,the bow wave doesn't get you,the wind isn't blanked by the tanker or the engine doesn/t die,-it is mathematically possible.
When cutting it that close,wear dark colored underwear & keep some touch-up paint aboard

Fair winds / Len

Of course, the whole point in doing that math is to show how easy it would be to avoid a collision with a big ship. If you happened to be asleep at the wheel, or in limited visibility or for whatever reason suddenly became aware that there was a ship bearing down on you (like the photo for example) it would only take seconds to get out of the way.

With the exceptions already noted, I've always felt like the risk of colliding with a ship to almost zero, assuming you're keeping watch with the Mark I eyeball and not too distracted posting to your facebook page.

[Don C L]

Originally Posted by StuM

It's so much easier in metric

A large container ship has a beam of about 50 m.
Assume 10m sailboat and 10m either side to clear the bow wave, so distance required to cross = 80m
6 knots = 3m/s. Time required = 80/3 or about 27 sec
20 knots = 10m/s. Distance traveled by freighter = 27x 10 = 270 meters.

Hmmm... the math... at least where I am I'm crossing the shipping lane every time I go out and that is the only part of the trip that gives me the willies... when you are going 4 or 5 or 6 knots and they are going 20, it is pretty darn amazing how fast they show up. And there are days when they come in a parade out of L.A. going north or west. I always feel like a sitting duck. Of course with radar you can see them coming and AIS will even do the math for you and let you know if you are on a collision course... but still I prefer a pretty clear day and and watching them with my trusty hand bearing compass at times to be sure the angle between us IS changing. I've never had a really close encounter but being a child of the old school, I won't cross the shipping lane in the fog, radar/ais or no.

[barnakiel]

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.

[Bulawayo]

....and then there are the clowns that think its fun to play with us little sail boats.
A few years ago I read about the captain of a Chinese boat that was arrested in Aden for running down a sailing boat on purpose. The radio transmissions had been recorded. The captain denied it was his vessel but the give away was the mast entangled in his anchor which he had not noticed.
In 2000, a date we recorded in detail, we were motoring in the GoA and were watching another Chinese vessel (an LPG carrier) approaching from astern. The weather was crystal clear and sea state was mirror flat. We called the LPG carrier several times via the VHF and received no response and when they were still about 1.5NM astern of us we turned on our second engine and changed course substantially, northwards, to move away from the ships course. It was immediately worrying to see the ship also change course to intercept us. We then excuted a 180 degree course change and increased our revs to 3200 rpm (flat out) and immediately they also changed course. Scared? You bet. We were transmitting repeatedly on the VHF with no response. The LPG carrier was closing rapidly on us when another voice came over the radio. It was the captain of a Singaporean registered vessel advising that he was recording the radio messages and was logging his radar and advising the LPG carrier to adjust his course immediately. This happened and the carrier passed us by around 150 meters away. We could clearly see the Chinese crew watching us from the bridge. We shall never know their intentions but we did video the whole matter, and still have the clip. We were preparing to drop our RIB into the water and rely on our 25hp to get us clear - we were scared like you cannot believe, especially with young children on board. We were tempted to open fire but believe that would have provoked the situation further and given the boat justification. This was an isolated incident and we have never had anything like it repeated. However, we are still super cautious of Chinese vessels. Nowadays, with AIS you at least know the name of the commercial vessel. In my opinion, AIS is one the most useful tools aiding in our safety.

Originally Posted by deblen

It never ceases to amaze me how some posters insist on their "right of way" (No such thing in COLREGS) & seem to believe that they have right of way due to wind or light colors & can "quote" such.
This makes it appear that they have memorized COLREGS & follow it to the letter.
But somehow,Rule 2 is forgotten.

Attachment 130137

Blame for collisions is usually apportioned to both parties.
Club racing rules are not a defence.

Len

[Don C L]

AIS tells quite a bit. I wouldn't be surprised if they start including who the captain is at the time. I have one experience with trying to hail a Chinese ship many years ago. They weren't trying to run us down though and to their credit they did at least pass along the message (as they approached Singapore) that they saw a vessel that appeared to be in need of help. We guessed at the time it was a language barrier issue.

[Cadence]

Originally Posted by deblen

Yes-it is easier in metric.
Make sure you are wearing metric underwear / L

Attachment 130140

I've seen that once. Don't wish to see it again. All of the electronics in the world would not have made a difference. Fortunately I caught my own stupidity and watched for lights on the ship, when you can see a red and green, and didn't luff crossing her bow. Between to jetties, you had someone looking out for you.

[Jim Cate]

Bulwayo, one can not begin to guess the intentions of the Chinese ship, but I wonder if this was a case of misunderstanding when the ship was attempting to actually avoid you, and you as the stand on vessel kept dodging about? We will never know...

But in the case that he was indeed attempting to hit or at least scare you, well, we're so often told how very slow to answer the helm large ships are, taking long distances to execute a turn. Seems to me that if in that situation, holding course until the ship was< a half mile distant, and then powering at right angles to his course at top speed would easily avoid collision... but then I was not there, fearing an apparent madman at the helm!

And the story of the mast hanging from the anchor... i've heard that for years, always with a different set of players. I think it is an urban... no, a yotties myth.

I'm pretty ready to believe stories of incompetence in ships officers (consider the well researched and reported case of Jessica Watson vs the Chinese ship), but a ship chasing a yacht around with malevolent intent is hard to take seriously.

Jim

[Don C L]

Originally Posted by Jim Cate

But in the case that he was indeed attempting to hit or at least scare you, well, we're so often told how very slow to answer the helm large ships are, taking long distances to execute a turn.
Jim

Funny, that's what I thought. But the incident we had, the freighter that passed us hung a u-turn to come back to check us! It was listing as it turned! We were all pretty shocked. It came back and hung another u-turn and left, without any radio communication attempt or response. The crew was all out on the bridge looking at us though.

[deblen]

Originally Posted by barnakiel

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.

No problem with Cat ferries. At 45kt,you will just have time to duck while a hull passes each side of you.
Watch for that rooster tail though

https://www.youtube.com/watch?v=2jMWgy57wlo

[barnakiel]

Originally Posted by deblen

No problem with Cat ferries. At 45kt,you will just have time to duck while a hull passes each side of you.
Watch for that rooster tail though

Yes. Very funny.

What about THEIR bridgedeck clearance? It is a known fact that deficient cat bridgedeck clearance leads to premature dismasting of monos that may try to sail in between the multi hulls.

;-)
b.