View unanswered posts | View active topics It is currently Sun Feb 25, 2018 5:19 pm



Reply to topic  [ 13 posts ] 
 lead line (sounding) 
Author Message
Moderator
User avatar

Joined: Tue Apr 12, 2005 9:34 am
Posts: 1471
Location: Virginia, USA
Post lead line (sounding)
I was having a discussion elsewhere about the procedure for casting the lead line to sound the depth of the sea. My thought was that the line was cast from the lee side of the ship. It was pointed out to me that in "The Oxford Companion To Ships and the Sea" (edited by Peter Kemp) "The lead is always cast from the weather side..." However, the book does not explain why. This comment is found (in my edition) on page 471 in the section titled "Lead Line". I also read the sections on "sounding" with no enlightenment.

Here is my thought process. Assuming, as the book does, that the ship is making a modest headway (10 knots or less), the lead line is heaved ahead of the ship so when the lead reaches the bottom, the line will be vertical beneath the ship. Why isn't the line also cast in the direction of the drift (to leeward) of the ship for the same reason? This could not be done from the weather side.

Is my logic flawed? Are there other sources that agree or disagree with Kemp's sources?

_________________
Don Campbell
"Whoever is strongest at sea, make him your friend."
Corcyraeans to the Athenians, 433 BC


Sat Mar 19, 2011 1:06 am
Profile
Lieutenant

Joined: Mon Oct 19, 2009 5:12 pm
Posts: 56
Post Re: lead line (sounding)
My only thought is that if the ships is leewardly then casting to lee could cause the line to snag on the hull and other protruberances. Casting to windward means that the line is naturally carried clear of the hull and it's tumblehome.

Only a guess of course.

Cy


Sat Mar 19, 2011 12:29 pm
Profile
Moderator
User avatar

Joined: Tue Apr 12, 2005 9:34 am
Posts: 1471
Location: Virginia, USA
Post Re: lead line (sounding)
cy wrote:
My only thought is that if the ships is leewardly then casting to lee could cause the line to snag on the hull and other protruberances. Casting to windward means that the line is naturally carried clear of the hull and it's tumblehome. Only a guess of course. Cy

Cy, are you agreeing with my logic or Kemp's book? The major difference is where the line is cast from -- the weather chains or the lee chains.

A sailor stationed in the weather chains (Kemp) can only cast straight ahead (or weatherly) otherwise, as you said, he would hit the ship. From the weather side, even casting straight ahead, the ship would move away from the line, creating a large angle with the bottom and an error in sounding the depth.

It makes sense to me that the line is cast from the lee side and cast even further to leeward. The ship will then drift toward the line causing the line to be vertical when the reading is taken.

_________________
Don Campbell
"Whoever is strongest at sea, make him your friend."
Corcyraeans to the Athenians, 433 BC


Sat Mar 19, 2011 2:10 pm
Profile
Lieutenant

Joined: Sat Oct 11, 2008 10:13 am
Posts: 106
Location: Sussex, England
Post Re: lead line (sounding)
Instinctively I would assume it to be cast from the leeward side, and would be interested to know why Kemp states otherwise.

As a bit of a tangent, I guess there would have to have been south paws on board to cast from the larboard side. Left handers make up about 10% of the population; on a small vessel that might mean only three or four men amongst the crew. How much of a skill was casting the lead; something that an ordinary seaman could undertake, or would he have to have been able?

_________________
Badger


Sun Mar 20, 2011 7:26 am
Profile WWW
Moderator
User avatar

Joined: Tue Apr 12, 2005 9:34 am
Posts: 1471
Location: Virginia, USA
Post Re: lead line (sounding)
Badger wrote:
Instinctively I would assume it to be cast from the leeward side, and would be interested to know why Kemp states otherwise.

Alaric, it is a shame that Kemp does not give a complete list of his sources. In the Preface, in addition to mentioning that he consulted many sources, he lists only three that might contain this information:
The Seaman's Dictionary - Henry Mainwaring
Marine Dictionary - William Falconer
Admiralty Manual of Seamanship

I found the last on-line in pdf format but using the weather side is not mentioned. I could not find copies of the first two. If anyone has access to either, could you check? Thanks,

_________________
Don Campbell
"Whoever is strongest at sea, make him your friend."
Corcyraeans to the Athenians, 433 BC


Sun Mar 20, 2011 1:54 pm
Profile
Lieutenant

Joined: Sat Oct 11, 2008 10:13 am
Posts: 106
Location: Sussex, England
Post Re: lead line (sounding)
Well a quick look at Falconer also puts the man to windward:

Sounding with the hand-lead, which is called heaving the lead by seamen, is. generally performed by a man who stands in the main-chains to windward. Having the line all ready to run out, without interruption, he holds it nearly at the distance of a fathom from the plummet, and having swung the latter backwards and forwards three or four times, in order to acquire the greater velocity, he swings it round his head,, and thence, as far forward as is necessary; so that, by. the lead's sinking whilst the ship advances, the line may be almost perpendicular when it reaches the bottom. The person founding then proclaims the depth of the water in a kind of song resembling the cries of hawkers in a city. Thus, if the mark of fathoms is close to the surface of the water, he calls 'By the mark five!' and as there is no mark, at 4, 6, 8, &c. he estimates those numbers, and calls, 'By the dip four,' &c. If he judges it to be a quarter, or an half more than any particular number, he calls, 'And a quarter five! and a half four,' &c. If he conceives the depth to be quarters more than a particular number, he calls it a quarter less than the next: thus, at four fathom and 3/4, he calls 'A quarter less five!' and so on.

_________________
Badger


Sun Mar 20, 2011 3:42 pm
Profile WWW
Moderator
User avatar

Joined: Tue Apr 12, 2005 9:34 am
Posts: 1471
Location: Virginia, USA
Post Re: lead line (sounding)
Badger wrote:
Well a quick look at Falconer also puts the man to windward:

Sounding with the hand-lead, which is called heaving the lead by seamen, is. generally performed by a man who stands in the main-chains to windward.


Thanks for looking Alaric. This information from Falconer certainly explains why Kemp said the weather side. But it still doesn't explain why. If an allowance is made for the forward progress of the ship, why isn't an allowance made for the leeward drift?

BTW: the reason I could not find William Falconer's book is that I was using the title listed by Kemp. After you found this quote, I double checked and found that the correct title is "An Universal Dictionary of the Marine". I was able to locate a pdf file (using Google Books) and downloaded it. For anyone else checking this, the information in Falconer's book is listed under the "Sounding" section.

_________________
Don Campbell
"Whoever is strongest at sea, make him your friend."
Corcyraeans to the Athenians, 433 BC


Sun Mar 20, 2011 5:44 pm
Profile
Lieutenant
User avatar

Joined: Mon Oct 19, 2009 3:27 am
Posts: 108
Location: East of everywhere, Canada
Post Re: lead line (sounding)
timoneer wrote:
If an allowance is made for the forward progress of the ship, why isn't an allowance made for the leeward drift?


Because if there is a current, the lead line will also be carried sideways along with the ship as it sinks?

Because you are probably going faster forward than you are to leeward, (unless you are hove to in a lot of wind or something) so the drift in the time it takes for the lead to hit bottom, would not be that great? (10kt is a pretty good clip for a square rigger. I've seen 9kt with just a reefed foresail, & had we used one, the lead would quickly be heading aft no matter how hard you flung it, never mind sideways)

Because if you are heeling, (which you certainly would be at nearly 10kt) you don't want a guy on the lee chains in case he fell in? He'd certainly get wetter... You always climb the weather shrouds; perhaps this just follows the tradition of staying on the weather side when possible?

Pardon for butting into the discussion... just some random guesses.

_________________
Alison

...life on land is DRY :(


Mon Mar 21, 2011 4:06 am
Profile
Moderator
User avatar

Joined: Tue Apr 12, 2005 9:34 am
Posts: 1471
Location: Virginia, USA
Post Re: lead line (sounding)
Alison wrote:
Because if there is a current, the lead line will also be carried sideways along with the ship as it sinks?
Alison, I gave some thought to current but since the original information was only directed at correcting for the forward progress, I wanted to know why some similar correction was not made for drift. One step at a time was my thought. Is the current as easy to estimate as forward progress and drift especially in strange waters? I don't know. And that is why I didn't want to complicate my question. I kind of hoped that any rationale (from a source like Falconer) for using the weather side might also address the current as well as the drift.

Alison wrote:
Because you are probably going faster forward than you are to leeward, (unless you are hove to in a lot of wind or something) so the drift in the time it takes for the lead to hit bottom, would not be that great? (10kt is a pretty good clip for a square rigger. I've seen 9kt with just a reefed foresail, & had we used one, the lead would quickly be heading aft no matter how hard you flung it, never mind sideways)
Ten knots was listed as the "maximum" that the sounding should be made. I guess throwing forward would have some limit based on human strength so any faster would be impossible to correct. In such a case, the lead would only hit the bottom after the ship had passed over giving an incorrect measurement. The sails could have been adjusted to made sure that the 10 knot limit was not exceeded. I agree that the drift should not be as great as the forward progress but if the ship is barely moving, the drift might be the only significant correction needed. Or, as you pointed out, the current, if it were significant.

Alison wrote:
Because if you are heeling, (which you certainly would be at nearly 10kt) you don't want a guy on the lee chains in case he fell in? He'd certainly get wetter... You always climb the weather shrouds; perhaps this just follows the tradition of staying on the weather side when possible?
A good comment but whether I was in the weather chains or the lee chains, I would certainly like a rope around my waist and maybe a mate on the other end. There would probably be someone nearby anyway to relay my soundings.

Alison wrote:
Pardon for butting into the discussion... just some random guesses.
Your thoughts are very welcome. Your comment that staying on the weather side is just tradition might be dead on. Staying on the weather side when climbing the rigging is certainly safer and might have carried over to the procedure of taking a sounding. I have found that when reading contemporary texts, the authors left out a lot of reasoning or explanation because, in many cases, it was so obvious to sailors of the period. To lubbers several hundred years later, it is not so obvious. My attempt to find a period reason for using the weather side may never be realized just because nobody thought to comment on it.

_________________
Don Campbell
"Whoever is strongest at sea, make him your friend."
Corcyraeans to the Athenians, 433 BC


Mon Mar 21, 2011 6:35 am
Profile
Commander

Joined: Sat Mar 31, 2007 12:27 am
Posts: 389
Location: Australia
Post Re: lead line (sounding)
THe lead was heaved ahead clear of the weather bow to avoid the possibility of the line catching on the hull or rudder - a very real possibility if the lead was heaved from the leeward chains. However, if the deep sea line was being used, the ship would usually be brought to and, if making leeway, the lead would sometimes be passed around the ship and heaved from the leeward chains and recovered to weather. If the ship was going free the lead could be heaved from the jib boom end and recovered at the mizen chains (where the soundings were read).


Wed Mar 23, 2011 11:09 am
Profile
Lieutenant

Joined: Sat Oct 11, 2008 10:13 am
Posts: 106
Location: Sussex, England
Post Re: lead line (sounding)
That makes perfect sense; thanks, Ionia.

_________________
Badger


Wed Mar 23, 2011 11:43 am
Profile WWW
Moderator
User avatar

Joined: Tue Apr 12, 2005 9:34 am
Posts: 1471
Location: Virginia, USA
Post Re: lead line (sounding)
IONIA wrote:
The lead was heaved ahead clear of the weather bow to avoid the possibility of the line catching on the hull or rudder - a very real possibility if the lead was heaved from the leeward chains.
Peter, If I read your post correctly, the aspect that you are focusing on is "after" the lead strikes the bottom or, in other words, during recovery of the line. If the line is on the lee side, the ship could drift into the line and foul the stern or be fouled by the side of the ship. That does make perfect sense. Is this from modern sailing experience or do you have a period source?

_________________
Don Campbell
"Whoever is strongest at sea, make him your friend."
Corcyraeans to the Athenians, 433 BC


Wed Mar 23, 2011 12:46 pm
Profile
Lieutenant
User avatar

Joined: Mon Oct 19, 2009 3:27 am
Posts: 108
Location: East of everywhere, Canada
Post Re: lead line (sounding)
timoneer wrote:
Is the current as easy to estimate as forward progress and drift especially in strange waters? I don't know. ...

Well, probably not. But then, it wouldn't be that much. Haven't got my notes handy, but when researching West Indies currents, I think I read the currents around Jamaica were listed as 3/4 kt or something like... Just for example.
Also haven't got my tide book handy, but I live near some of the highest tides in the world, & up the channel we see something like 3-4kt on a spring tide at its fastest. Generally they would see a lot less current unless they were going through similar smaller channels, which is why I thought it might be a negligible effect.
timoneer wrote:
whether I was in the weather chains or the lee chains, I would certainly like a rope around my waist and maybe a mate on the other end. ...

Um... I don't think they did that...! If you didn't get a safety line going aloft you sure wouldn't get one tucked into a channel! Unless it was really rough... Or DID they...?
timoneer wrote:
I have found that when reading contemporary texts, the authors left out a lot of reasoning or explanation because, in many cases, it was so obvious to sailors of the period. To lubbers several hundred years later, it is not so obvious.

Wow... I'll say. So many little details you would like to know, & you can't find ANYWHERE, just because everyone took some things for granted. I would love to find the contemporary equivalent of "Seamanship for Dummies" :mrgreen:

_________________
Alison

...life on land is DRY :(


Wed Mar 23, 2011 9:08 pm
Profile
Display posts from previous:  Sort by  
Reply to topic   [ 13 posts ] 

Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group.
Designed by STSoftware for PTF.