Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 26-08-2016, 18:31   #91
Senior Cruiser
 
StuM's Avatar

Cruisers Forum Supporter

Join Date: Nov 2013
Location: Port Moresby,Papua New Guinea
Boat: FP Belize Maestro 43
Posts: 6,709
Re: Is all the new technology worth it?

Quote:
Originally Posted by skipmac View Post
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.
__________________

__________________
StuM is offline   Reply With Quote
Old 26-08-2016, 18:31   #92
Registered User
 
deblen's Avatar

Join Date: Oct 2014
Location: Grand Manan,N.B.,Canada N44.40 W66.50
Boat: Mascot 28 pilothouse motorsailer 28ft
Posts: 1,400
Images: 1
Re: Is all the new technology worth it?

Quote:
Originally Posted by deblen View Post
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

Click image for larger version

Name:	Fog.jpg
Views:	48
Size:	73.3 KB
ID:	130139
__________________

__________________
My personal experience & humble opinions-feel free to ignore both
deblen is offline   Reply With Quote
Old 26-08-2016, 18:35   #93
Registered User
 
deblen's Avatar

Join Date: Oct 2014
Location: Grand Manan,N.B.,Canada N44.40 W66.50
Boat: Mascot 28 pilothouse motorsailer 28ft
Posts: 1,400
Images: 1
Re: Is all the new technology worth it?

Quote:
Originally Posted by StuM View Post
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

Click image for larger version

Name:	<a title=Ferry bow.jpg Views: 53 Size: 90.5 KB ID: 130140" style="margin: 2px" />
__________________
My personal experience & humble opinions-feel free to ignore both
deblen is offline   Reply With Quote
Old 26-08-2016, 18:39   #94
Senior Cruiser
 
StuM's Avatar

Cruisers Forum Supporter

Join Date: Nov 2013
Location: Port Moresby,Papua New Guinea
Boat: FP Belize Maestro 43
Posts: 6,709
Re: Is all the new technology worth it?

Quote:
Originally Posted by deblen View Post
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
__________________
StuM is offline   Reply With Quote
Old 26-08-2016, 20:05   #95
Senior Cruiser
 
skipmac's Avatar

Cruisers Forum Supporter

Join Date: Oct 2007
Location: 29 49.16 N 82 25.82 W
Boat: Pearson 422
Posts: 12,373
Re: Is all the new technology worth it?

Quote:
Originally Posted by StuM View Post
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.
__________________
The water is always bluer on the other side of the ocean.
skipmac is offline   Reply With Quote
Old 26-08-2016, 20:14   #96
Senior Cruiser
 
skipmac's Avatar

Cruisers Forum Supporter

Join Date: Oct 2007
Location: 29 49.16 N 82 25.82 W
Boat: Pearson 422
Posts: 12,373
Re: Is all the new technology worth it?

Quote:
Originally Posted by deblen View Post
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.
__________________
The water is always bluer on the other side of the ocean.
skipmac is offline   Reply With Quote
Old 27-08-2016, 10:26   #97
Moderator
 
Don C L's Avatar

Join Date: Sep 2014
Location: Channel Islands, CA
Boat: 1962 Columbia 29 MK 1 #37
Posts: 4,375
Images: 34
Re: Is all the new technology worth it?

Quote:
Originally Posted by StuM View Post
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.
__________________
DL
Pythagoras
1962 Columbia 29 MKI #37
Don C L is offline   Reply With Quote
Old 27-08-2016, 13:40   #98
Senior Cruiser

Cruisers Forum Supporter

Join Date: Aug 2009
Location: between the devil and the deep blue sea
Boat: a sailing boat
Posts: 17,314
Re: Is all the new technology worth it?

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.
__________________
barnakiel is offline   Reply With Quote
Old 27-08-2016, 13:42   #99
Senior Cruiser

Cruisers Forum Supporter

Join Date: Dec 2010
Location: Cruising Indian Ocean / Red Sea - home is Zimbabwe
Boat: V45
Posts: 1,282
Re: Is all the new technology worth it?

....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.



Quote:
Originally Posted by deblen View Post
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
__________________
Bulawayo is offline   Reply With Quote
Old 27-08-2016, 14:06   #100
Moderator
 
Don C L's Avatar

Join Date: Sep 2014
Location: Channel Islands, CA
Boat: 1962 Columbia 29 MK 1 #37
Posts: 4,375
Images: 34
Re: Is all the new technology worth it?

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.
__________________
DL
Pythagoras
1962 Columbia 29 MKI #37
Don C L is offline   Reply With Quote
Old 27-08-2016, 14:31   #101
Registered User
 
Cadence's Avatar

Join Date: Dec 2008
Location: SC
Boat: None,build the one shown of glass, had many from 6' to 48'.
Posts: 6,053
Re: Is all the new technology worth it?

Quote:
Originally Posted by deblen View Post
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.
__________________
Cadence is offline   Reply With Quote
Old 27-08-2016, 14:41   #102
Senior Cruiser
 
Jim Cate's Avatar

Cruisers Forum Supporter

Join Date: May 2008
Location: cruising SW Pacific
Boat: Jon Sayer 1-off 46 ft fract rig sloop strip plank in W Red Cedar
Posts: 11,447
Re: Is all the new technology worth it?

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
__________________
Jim and Ann s/v Insatiable II , lying Port Cygnet, Tasmania once again
Jim Cate is offline   Reply With Quote
Old 27-08-2016, 14:51   #103
Moderator
 
Don C L's Avatar

Join Date: Sep 2014
Location: Channel Islands, CA
Boat: 1962 Columbia 29 MK 1 #37
Posts: 4,375
Images: 34
Re: Is all the new technology worth it?

Quote:
Originally Posted by Jim Cate View Post
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.
__________________
DL
Pythagoras
1962 Columbia 29 MKI #37
Don C L is offline   Reply With Quote
Old 27-08-2016, 15:44   #104
Registered User
 
deblen's Avatar

Join Date: Oct 2014
Location: Grand Manan,N.B.,Canada N44.40 W66.50
Boat: Mascot 28 pilothouse motorsailer 28ft
Posts: 1,400
Images: 1
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.
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

__________________
My personal experience & humble opinions-feel free to ignore both
deblen is offline   Reply With Quote
Old 27-08-2016, 16:04   #105
Senior Cruiser

Cruisers Forum Supporter

Join Date: Aug 2009
Location: between the devil and the deep blue sea
Boat: a sailing boat
Posts: 17,314
Re: Is all the new technology worth it?

Quote:
Originally Posted by deblen View Post
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.
__________________

__________________
barnakiel is offline   Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
New RO Filter Technology San Juan Sailor Plumbing Systems and Fixtures 0 29-01-2010 13:36
New Solar Cell technology!! shadow Off Topic Forum 14 05-11-2008 16:12
New solar technology on the way NoTies Electrical: Batteries, Generators & Solar 14 07-04-2007 14:00



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 05:09.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.