Please visit our home site at www.TRILOBOATS.com.

Anke and I are building our next boat, and writing about it at ABargeInTheMaking.blogspot.com. Access to the net comes and goes, so I'll be writing in fits and spurts.

Please feel free to browse the archives, leave comments where you will and write, and I'll respond as I can.

Fair winds!

Dave and Anke
triloboats swirl gmail daughter com

Saturday, March 3, 2012

Our Lead Line: Plumbing the Depths

The Boys wanted to pull a joke on the Old Man, who was famous for tasting the bottom as brought up by the armed lead. He claimed to be able to find his way around the coast and banks by taste alone, but was suspected of spinnin' yarn.

So they stowed away a choice specimen of soil from ashore, and bade their time. Soon enough a fog settled in to stay, and they felt their way along for a week before judging the time right.

On sounding, and without the Old Man seeing, they re-armed the lead with their impostor, handed the lead over, and awaited results.

As usual, the Old Man took a contemplative lick at the end of the lead.

His eyes popped wide, and he shouted, "Batten down, then say your prayers, Boys! Nantucket Island is sunk and we're hove to over Mrs. Grady's henhouse!!" 

The Boys could never decide how he'd come by the taste of that!

One of those Yarns sloshing about in the Tide


One of the most important bits of information to a sailor is the depth - of the bottom or of the water, depending on your focus... means the same.

With that knowledge, one can follow a bottom contour, determine depth for anchoring, detect a rising, falling or level bottom.

An ancient and honored means is the lead line, or simply, the lead.

This is a heavy weight at the end of a line which is marked off to indicate fathoms. Drop it overboard till it hits bottom, note the depth, bounce it a couple of times to get the feel, and pull it up. That's the short version.

It will often have a cup, at the bottom into which grease of some sort is smeared (arming the lead)... grit from the bottom sticks to the grease, giving further clues to bottom character.

Our lead isn't. By that I mean we hacksawed the end off a fat, stainless steel prop shaft from a beached wreck, that was nicely tapered and even drilled to accept the missing propeller. We filed  the corners smooth and strung it with nylon parachute cord. We've also used painted window sash weights, which work great. In either case, watch for chafe at the line loop.

There's a traditional way to mark the line... some system involving rag, leather, beads and washers or somesuch. Not having been taught at rope's end, I can't hang on to stuff like that! So we made our own system of knots, inspired by the abacus.

Knots appear in clusters, one fathom apart, measured and read from the knot nearest the lead. Each cluster may have one or two groups of knots.

Fathom 1 is a single knot, six feet from the bottom of the lead (bottom of the image to the left). One through four four fathoms are a single group cluster each, with one knot per fathom.

Fathom 5 is a single knot. From here on out, the first group of knots within a cluster represents a multiple of 5 fathoms, five per Knot. 
If there is only one group within a cluster, then it's the first group (that is, it indicates a multiple of five).

If there are two groups within a cluster, then the first group is fives, and the second is ones.
The trick is to space the knots in a single group closely, and separate the groups enough you can feel the gap blind-folded, with cold, gloved fingers (believe me, comes in handy!). To read (eyes closed, every time), we close our fingers on the lead side of the cluster and zii-iiip. That fast. If i's were knots that'd read 13ftm (okay... now we can peek).

You may notice that there are some ambiguities.  Fathoms 1 and 5, 2 and 10, 3 and 15, 4 and 20 have like clusters. In practice, this is no problem if you're even barely aware of how much line's going out.

We cast ahead in proportion to depth and the boat's forward motion. Ideally, we end up directly over the lead as it hits bottom. If we cast from the windward side, the boat doesn't overrun our line.

The line is clipped to its box, which is clipped to the boat. As it runs out, we hold our hand loosely, palm up, making an open ring with thumb and forefinger around the running line. We avoid slowing the run at all, but stand ready to pinch off if we have no bottom past a depth of interest. For example, if we're looking for 10ftm, no sense running out 20... we'll clamp down and haul in.

Once it hits bottom, we haul any slack and read the next cluster outboard, then bounce the lead once or twice. Information comes up the line; The suckkk of mud or silt, thud of sand, chshhh of gravel, TINK of bedrock or boulder, tink of cobble and limp lettuce feel of weed. In fact, we armed the lead for a year, but never learned anything further. It did confirm our sense of touch, however.

We haven't had much luck with reels (in few tries, I must say). On retrieval, we haul with a circular 'pedal' motion -palms up and coming from below the line (generally a good slack line movement... we practice speed as sometimes we need it!), spilling the fall onto deck (don't step in the bights!). We place the lead well clear of the heap between casts. Once done, we overhaul it, spilling it into its tackle box which lives in easy reach.

Call-out protocols help things run smoothly. Info gets shared with all on deck. It helps if we've already discussed our target (good holding in ten to five fathoms, say). Before casting we call, "SOUNDING!" (avoids heart-attack for the foredeck ape when the SPLASH of the lead surpises and gushes water). If no bottom is found, we call, "NO BOTTOM AT 15!" If we hit bottom, its, "SAND AT 8 FATHOMS."

Often, the one at the bow is standing by to drop anchor. Sometimes the helm calls the DROP, and sometimes the bow, by prearranged decision. In the latter case, they're waiting for the target result from sounding, and drop on conditions met.

All this is easier than it sounds, and practice makes perfect. The lead line is one of those things that can be made and practiced while waiting to get on the water. Even if one has electronic depth sounders, a lead-line is a fail-safe backup.

Our little plumber's helper!


NOTE: Spilling line means just dumping it in a heap. It's very fast and pays back out beautifully if left essentially undisturbed. We might carefully ease it to one side, but never handle it in a way that might 'toss' it like salad. Undoing snarls in the dark while racing toward shoals is a teachable moment!



11 comments:

  1. That's the next thing on our "for the boat" list, a good lead line. We've become a bit complacent sailing Florida's sandy/muddy waters.

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    Replies
    1. The only leadline marking I remember was blue serge, unlucky for some.. wink wink.. apparently the nuns used to have blue serge undergarments, or so the old lecturer at nautical college told us impressionable young cadets. We never got up the courage to ask him how he knew that.

      I reckon an electric depth sounder is the most important bit of electronics for any deeper drafted boat, would rate it above a gps for inshore work. I had it die on my last boat, it was a real hardship that my makeshift lead could not really make up for. Fitting two depth sounders for redundancy makes sense on bigger expensive boats. But maybe that is just my deep draughted perspective...

      I am really enjoying your writing Dave, thought provoking and well written.

      Delete
    2. ohh, forgot to mention, blue serge was 13 fathoms...

      Delete
    3. Hmm. Blue undies to signal, "Out of luck, Sailor!"?

      Delete
    4. Hmm. Blue undies to signal, "Out of luck, Sailor!"?

      Delete
  2. I use the traditional marks, which evolved for use in cold, dark conditions. I learned _red_ wool serge at 13 BTW. Anyway, it works well for me, at night you can usually tell the marks by touching them to your lips if needed. Hence the traditional mark system emphasized materials of different tactile presentation. I have string, cotton rag, wool serge and leather marks. My toggle is at 1 fathom as a first mark.

    Glenn

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    Replies
    1. Hi Glenn,

      My hat's off to ye!

      Not having tried it, I've wondered if the stringy bits might foul, especially if there's something at the end of it... ever have any problems with that?

      Could you give a run-down of the traditional system?

      Dave

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  3. I've never had my marks foul. The traditional marks are:
    2 Fa, 2 leather strips
    3 Fa, 3 leather strips
    5 Fa, White Cotton cloth
    7 Fa, Red Wool cloth
    10 Fa, Leather with a round hole in it (1/2" - 3/4" hole)
    13 Fa, Blue Serge cloth
    15 Fa, White Cotton again
    17 Fa, Red Wool again
    20 Fa, String with 2 knots in it

    I didn't remember the blue serge when I made mine, and just repeated the 3 Fa mark. I also used shot line (like Para cord, but about half the dia) instead of leather on the 2, 3 and 13 Fa marks. I didn't bother with 20 Fa, because it's the end of mine. Traditionally the sounding line would be 25 Fa long. My "lead" is one of those 3 1/2 pound bronze ones from Woodenboat(TM) which my brother gave me as a gift. I'm a small boat sailor (16 - 18 ft) and it's a lot easier to handle in a small boat than the 7 pound traditional weight.

    Glenn
    Master of the
    Sloop - Boat
    FEATHER
    and the
    Terror
    of
    Scow Bay

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    Replies
    1. Thanks, Glenn!

      I can see why my mind shies away from that like a spooked horse! I'm okay at 2,3... but then to odds is a stretch. Insert 10 and 20 with odds between. And the markings! 15 and 17 repeating 5 and 7 makes some sense to me, but thereafter I'm melting down.

      I must say that I'm surprised that one can tell red, white and blue apart in the dark, as well as cotton, wool and serge. Amazing.

      It's so interesting to me which traditional systems were utterly systematic (points system, for example) and which seem to be the workings of minds on a completely different track from mine.

      I generally favor tradition, as it's more likely to be held in common among sailors. But the important thing is to be able to grasp the system adopted, and set that as the ship's standard... which all aboard understand and can fluently use.

      Thanks again for the run-down!

      Dave

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    2. " must say that I'm surprised that one can tell red, white and blue apart in the dark, as well as cotton, wool and serge. Amazing."

      That's the point of the cotton, wool and serge. You can't tell the colours in the dark. But you can feel the difference between the fabrics; when hands are too numb, touch the mark to your lips. It helps to use a rough wool and a smooth serge, the serge is still pretty easy to tell from the cotton by feel.

      Glenn

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    3. Hi Glenn,

      Hmm... think I'll stick with our system... let my fingers do the walkin', rather than walkin' on my lips! 8)

      But thanks for the info. Always good to review the alternatives, and may come in handy on someone else's boat.

      Dave

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