Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 24-07-2016, 10:06   #151
Registered User
 
hoppy's Avatar

Join Date: Sep 2009
Location: Melbourne, Australia
Boat: Jeanneau Sun Odyssey 40
Posts: 2,766
Re: Do use Day Shapes

Quote:
Originally Posted by Lodesman View Post
What part of (this is not a debate about whether 500 yards is appropriate, it's just an example for this illustration) was unclear to you? I just picked an arbitrary figure to illustrate that a slow moving boat, as one under sail, needs to make a larger course alteration, than the faster boat would, to have the same effect. The example had you altering at a distance of 2 miles - that is not a "last minute panic manoeuvre."
You apparently didn't understand the context of my original point, and seem reluctant to actually read and understand further explanation. Believe what you will. I'm not wasting any more time on this.
You picked an arbitrary figure to make your point and made that figure large enough to get some wow factor out of the numbers you calculated. You could perhaps moonlight for Fox News.

If you have a show boat, an unmanoeuvrable boat, you will sail it accordingly and plan further ahead.

Plan ahead and don't end up in irons.....
__________________

__________________
S/Y Jessabbé http://www.jessabbe.com/
hoppy is offline   Reply With Quote
Old 24-07-2016, 10:13   #152
Registered User
 
TeddyDiver's Avatar

Join Date: Aug 2010
Location: Arctic Ocean
Boat: Under construction 35' ketch
Posts: 1,685
Images: 2
Re: Do use Day Shapes

Quote:
Originally Posted by hoppy View Post
You picked an arbitrary figure to make your point and made that figure large enough to get some wow factor out of the numbers you calculated. You could perhaps moonlight for Fox News.

If you have a show boat, an unmanoeuvrable boat, you will sail it accordingly and plan further ahead.

Plan ahead and don't end up in irons.....
So to keep you happy lets assume it's you motorsailing 6kn and a ferry doing 25kn
__________________

__________________
TeddyDiver is offline   Reply With Quote
Old 24-07-2016, 11:32   #153
Registered User
 
hoppy's Avatar

Join Date: Sep 2009
Location: Melbourne, Australia
Boat: Jeanneau Sun Odyssey 40
Posts: 2,766
Re: Do use Day Shapes

Quote:
Originally Posted by TeddyDiver View Post
So to keep you happy lets assume it's you motorsailing 6kn and a ferry doing 25kn
I still don't see the point of throwing up figures to highlight the bleeding obvious that hopefully all here already understands. It's like using maths to explain why a slow truck needs a much bigger gap in oncoming traffic to overtake a vehicle than a high speed sportscar needs.

If you drive a slow car you overtake within its limitations which includes planning ahead more than the driver of a fast car needs to.

If you sail a slow boat, you plan ahead more and then you don't end up in irons (unless you screw up)


Sent from my iPhone using Cruisers Sailing Forum
__________________
S/Y Jessabbé http://www.jessabbe.com/
hoppy is offline   Reply With Quote
Old 24-07-2016, 12:20   #154
Senior Cruiser

Cruisers Forum Supporter

Join Date: Nov 2005
Location: Out there doin' it
Boat: 47' Olympic Adventure
Posts: 2,444
Re: Do use Day Shapes

Quote:
Originally Posted by hoppy View Post
I still don't see the point of throwing up figures to highlight the bleeding obvious that hopefully all here already understands.
It's clearly not bleeding obvious to some here. If you assume the motorsailing vessel is sailing, then you might also assume it's going at a comparable speed to yourself - your little "couple degree" manoeuvre made in due time will be insufficient when that vessel is suddenly a lot closer, a lot sooner than expected. Then any corrective action will only have to be that much larger.
That is why power gives way to sail, except where the rules state otherwise. No one has "right of way" as you previously implied.
__________________
Lodesman is offline   Reply With Quote
Old 24-07-2016, 12:57   #155
Moderator
 
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: [S]Hamble (Spring and Fall)[/S], Cowes (Winter), Baltic (Summer) (the boat!); somewhere in the air (me!)
Boat: Cutter-Rigged Moody 54
Posts: 17,233
Re: Do use Day Shapes

Quote:
Originally Posted by hoppy View Post
You picked an arbitrary figure to make your point and made that figure large enough to get some wow factor out of the numbers you calculated. You could perhaps moonlight for Fox News.

If you have a show boat, an unmanoeuvrable boat, you will sail it accordingly and plan further ahead.

Plan ahead and don't end up in irons.....
Now that we're actually talking about appropriate crossing distances, although Lodesman didn't want to --

500 yards or meters is roughly 2 1/2 cables. That's far too close if passing ahead of a fast moving ship. For that you really want at least a mile. I was in this very situation just a few days ago, crossing the Gulf of Finland from Helsinki to Tallinn, going through the gap in the TSS. Two tankers coming from St. Petersburg in the West-bound lane showing CPA of a cable or two, or less than a cable. I was having such a great sail -- hard on the wind, making 8 to 9 knots in 12 to 14 knots of wind -- it was glorious and I really didn't want to go around or heave to. I couldn't alter to starboard because I would have run into the TSS. I talked to the Russian tanker driver and agreed that he would alter to starboard as soon as the other tanker passed him, which he kindly did. In the event, the CPA was less than a mile, but CPA in a perpendicular crossing doesn't occur when you're on the other vessel's course line. I was about a mile off when I crossed his course line. Tight but marginally ok. It looked scary and I would have never done it without AIS. 500 yards?? Fuggedaboutit.

Crossing behind is a different story, however. In open water and good viz, 4 or 5 cables might be enough.

500 yards? Might be ok in crowded coastal waters, but never crossing ahead.

Between two yachts maybe less than 500 yards would be ok, even in open water.

In any case, there's nothing to object to in Lodesman's hypothetical.
__________________
Dockhead is offline   Reply With Quote
Old 24-07-2016, 13:21   #156
Registered User
 
hoppy's Avatar

Join Date: Sep 2009
Location: Melbourne, Australia
Boat: Jeanneau Sun Odyssey 40
Posts: 2,766
Re: Do use Day Shapes

Quote:
Originally Posted by Lodesman View Post
It's clearly not bleeding obvious to some here. If you assume the motorsailing vessel is sailing, then you might also assume it's going at a comparable speed to yourself - your little "couple degree" manoeuvre made in due time will be insufficient when that vessel is suddenly a lot closer, a lot sooner than expected. Then any corrective action will only have to be that much larger.
That is why power gives way to sail, except where the rules state otherwise. No one has "right of way" as you previously implied.
That sounds like poor seamanship to just "assume" they are doing a comparable speed. You should be observing the other yacht and taking bearings.

It's very easy for two similarly sized yachts to be doing several knots different speeds in the same wind conditions, in fact that can apply to identical yachts. I know that with my yacht, in some conditions I can pinch to windward at 4 knots and pick up another 2 knots by baring away by 20 or 30 degrees.

So if you're not paying attention, you're going to get caught out by other sailing vessels. I suppose that if you are on port tack and the fast sailing yacht is on starboard, you will end up in irons when at the last minute you realise that they are actually sailing.
__________________
S/Y Jessabbé http://www.jessabbe.com/
hoppy is offline   Reply With Quote
Old 24-07-2016, 13:30   #157
Registered User
 
hoppy's Avatar

Join Date: Sep 2009
Location: Melbourne, Australia
Boat: Jeanneau Sun Odyssey 40
Posts: 2,766
Re: Do use Day Shapes

Quote:
Originally Posted by Dockhead View Post
Now that we're actually talking about appropriate crossing distances, although Lodesman didn't want to --

500 yards or meters is roughly 2 1/2 cables. That's far too close if passing ahead of a fast moving ship. For that you really want at least a mile. I was in this very situation just a few days ago, crossing the Gulf of Finland from Helsinki to Tallinn, going through the gap in the TSS. Two tankers coming from St. Petersburg in the West-bound lane showing CPA of a cable or two, or less than a cable. I was having such a great sail -- hard on the wind, making 8 to 9 knots in 12 to 14 knots of wind -- it was glorious and I really didn't want to go around or heave to. I couldn't alter to starboard because I would have run into the TSS. I talked to the Russian tanker driver and agreed that he would alter to starboard as soon as the other tanker passed him, which he kindly did. In the event, the CPA was less than a mile, but CPA in a perpendicular crossing doesn't occur when you're on the other vessel's course line. I was about a mile off when I crossed his course line. Tight but marginally ok. It looked scary and I would have never done it without AIS. 500 yards?? Fuggedaboutit.

Crossing behind is a different story, however. In open water and good viz, 4 or 5 cables might be enough.

500 yards? Might be ok in crowded coastal waters, but never crossing ahead.

Between two yachts maybe less than 500 yards would be ok, even in open water.

In any case, there's nothing to object to in Lodesman's hypothetical.
Call me chicken, but 1 mile is not enough distance for me to feel happy about crossing in front of a ship. If I do it, it's only because I've seen on my AIS that the ship has changed it's course to pass behind me. In that situation, I'm not going to change course, I keep it steady and let the ship dictate the CPA.
__________________
S/Y Jessabbé http://www.jessabbe.com/
hoppy is offline   Reply With Quote
Old 24-07-2016, 13:51   #158
Moderator
 
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: [S]Hamble (Spring and Fall)[/S], Cowes (Winter), Baltic (Summer) (the boat!); somewhere in the air (me!)
Boat: Cutter-Rigged Moody 54
Posts: 17,233
Re: Do use Day Shapes

Quote:
Originally Posted by hoppy View Post
Call me chicken, but 1 mile is not enough distance for me to feel happy about crossing in front of a ship. If I do it, it's only because I've seen on my AIS that the ship has changed it's course to pass behind me. In that situation, I'm not going to change course, I keep it steady and let the ship dictate the CPA.
Good for you. I agree. I said one mile is a minimum for me. In any case, I much prefer to pass behind.

I had a very interesting conversation about this with commercial mariners on G Captain. We were discussing how to cross. They were very surprised to hear how much we hate to pass ahead.
__________________
Dockhead is offline   Reply With Quote
Old 24-07-2016, 14:02   #159
Registered User
 
hoppy's Avatar

Join Date: Sep 2009
Location: Melbourne, Australia
Boat: Jeanneau Sun Odyssey 40
Posts: 2,766
Re: Do use Day Shapes

Quote:
Originally Posted by Dockhead View Post
In any case, there's nothing to object to in Lodesman's hypothetical.
Except that it is out of context of the topic....

If the faster vessel is appears to be sailing and would be the stand on vessel, then he will need to change course. If it turns out that they were indeed sailing, he made the right course of action, if they were motor sailing, he still made the right course of action, even if he was the stand on vessel.

If you want leave a half mile CPA to another sailing vessel, you are going to have to change course well before you'll be able to see an inverted cone. If the other yacht is motorsailing with their headsail up and you are both (motor) sailing to windward, you are probably not going to see the cone until you have crossed tacks.

In a crossing situation the stand on vessel has very little say about how much the CPA will be.

If the other yacht only has the main up, then it is likely that you will assume they are motorsailing, regardless of whether they have a cone or not. If you guessed it wrong, then you have to deal with it anyway.

The only real problem is when you know the other yacht is motorsailing, so you hold course, but they continue to pretend they are sailing and don't stand to.
__________________
S/Y Jessabbé http://www.jessabbe.com/
hoppy is offline   Reply With Quote
Old 24-07-2016, 14:07   #160
Registered User
 
hoppy's Avatar

Join Date: Sep 2009
Location: Melbourne, Australia
Boat: Jeanneau Sun Odyssey 40
Posts: 2,766
Re: Do use Day Shapes

Quote:
Originally Posted by Dockhead View Post
I had a very interesting conversation about this with commercial mariners on G Captain. We were discussing how to cross. They were very surprised to hear how much we hate to pass ahead.
I've always thought that all car drivers should first ride a motorcycle in traffic to give them a better appreciation of what it's like for us bike riders.

Maybe all commercial mariners should go sailing around shipping before they start working on ships.
__________________
S/Y Jessabbé http://www.jessabbe.com/
hoppy is offline   Reply With Quote
Old 24-07-2016, 14:16   #161
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: 10,051
Send a message via Skype™ to Jim Cate
Re: Do use Day Shapes

I think it would also be beneficial for yotties to spend time on the bridge of a merchant vessel. My one time thus gave me a very different idea about how visible we are to them. The big difference is that we,being low to the water, see them, and other yachts silhouetted against the sky, and they see us against the sea... a much less distinctive contrast. I was surprised how hard it was to see yachts, even in excellent conditions.

Jim
__________________
Jim and Ann
s/v Insatiable II, back in Hobart for slipping and other unpleasant activities.
Jim Cate is offline   Reply With Quote
Old 24-07-2016, 14:24   #162
Registered User
 
El Pinguino's Avatar

Join Date: Aug 2013
Location: el campo
Boat: 39' Westerly Sealord
Posts: 3,478
Re: Do use Day Shapes

Minimum CPA? Far too many variables to lay down any rules.......

Sound signals? Don't think any big ships will be listening....
El Pinguino is offline   Reply With Quote
Old 24-07-2016, 14:29   #163
Guy
Registered User

Join Date: Feb 2013
Location: Boat is on the Rio Dulce
Boat: Seafarer36c
Posts: 3,584
Re: Do use Day Shapes

[QUOTE=Jim Cate;2173670] I was surprised how hard it was to see yachts, even in excellent conditions.

That must be why a big ship captain told me we should sleep at night, not during the day. They can see our lights just fine at night.
__________________
Guy is offline   Reply With Quote
Old 24-07-2016, 17:39   #164
Senior Cruiser

Cruisers Forum Supporter

Join Date: Nov 2005
Location: Out there doin' it
Boat: 47' Olympic Adventure
Posts: 2,444
Re: Do use Day Shapes

Quote:
Originally Posted by hoppy View Post
That sounds like poor seamanship to just "assume" they are doing a comparable speed. You should be observing the other yacht and taking bearings.

It's very easy for two similarly sized yachts to be doing several knots different speeds in the same wind conditions, in fact that can apply to identical yachts. I know that with my yacht, in some conditions I can pinch to windward at 4 knots and pick up another 2 knots by baring away by 20 or 30 degrees.
Taking bearings? Are you serious? If a risk of collision exists, then there is very little to no change in bearing - how do you propose to determine the other vessel's speed with no bearing change?

So if another SO40 is coming at you on the opposite beam reach, and you can only get 3 kts out of the light wind, you'll assume the other guy is going 9 kts, because otherwise it would be bad seamanship?
__________________
Lodesman is offline   Reply With Quote
Old 24-07-2016, 17:46   #165
Registered User

Join Date: Apr 2007
Location: Australia
Boat: Island Packet 40
Posts: 1,298
Images: 7
Re: Do use Day Shapes

Quote:
Originally Posted by Jim Cate View Post
I think it would also be beneficial for yotties to spend time on the bridge of a merchant vessel. My one time thus gave me a very different idea about how visible we are to them. The big difference is that we,being low to the water, see them, and other yachts silhouetted against the sky, and they see us against the sea... a much less distinctive contrast. I was surprised how hard it was to see yachts, even in excellent conditions.

Jim
Precisely, it's similar to lefty voting - vote early and vote often. Dodge early, dodge often and keep dodging.
__________________

__________________
RaymondR 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 Najad Hull Shapes: Are They Good for Cruising? Nilus Monohull Sailboats 23 24-02-2015 15:38
Galley shapes, along side , 'L' or 'U' ReneJK Challenges 34 23-09-2014 23:49
Day Shapes searcher Rules of the Road, Regulations & Red Tape 10 09-09-2010 12:58
Day Shapes Steve Kidson Navigation 21 11-10-2007 20:52


Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 09:26.


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.