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!