Super-simple cheap depth gauging? Or will learning to splice cost me a fortune?

[Greenheart]

I like the idea of learning the depth while doing without electricity; but not the prospect of needing a line repeatedly knotted at intervals, making its use much harder.

Since light line is available in every colour today, perhaps I could revive the lead & line by splicing together short lengths in different colours - the shallowest 2 meters a deep blood-red, then 2 meters of orange, then of yellow, then pale green, then blue...

...such that when the lead hits the seabed, I needn't look for numbered knots to discern the depth & danger. The more red the colour, the shallower the water.

I begin to wonder if it hasn't been done already. Did you hear it here, first?

No use for accurate soundings sought while navigating, but handy for creek-crawling. Is splicing braided line a hard technique to learn slowly on long winter nights?

 

[oldbilbo]

That's all well 'n good, but it is rumoured that the original, recommended arrangement of a succession of 'leather strips, feathers, calico, serge' was to facilitate conning the sounding by feel, in the dark, while one's unlit 'darkened' frigate or man-o'-war was creeping into some unsuspecting Napoleonic harbour, intent on wreaking havoc.

These days, I s'pose one could do something similar, creeping OUT of some dim-lit marina or West Country harbour before dawn, thus avoiding the payment of mooring dues.

......it became traditional to tie marks at intervals along the line. These marks were made of leather, calico, serge and other materials, and so shaped and attached that it was possible to "read" them by eye during the day or by feel at night......

The question is whether you'll calibrate in traditional fathoms or EU metres.....

 

[Greenheart]

Hmm, thanks Bilbo. But if I anticipate any nocturnal navigation, I hope I'll have justified an electric sounder. My 'cleverness' is doing without lots of crud tacked on to the line.

 

[john_morris_uk]

That's all well 'n good, but it is rumoured that the original, recommended arrangement of a succession of 'leather strips, feathers, calico, serge' was to facilitate conning the sounding by feel, in the dark, while one's unlit 'darkened' frigate or man-o'-war was creeping into some unsuspecting Napoleonic harbour, intent on wreaking havoc.

These days, I s'pose one could do something similar, creeping OUT of some dim-lit marina or West Country harbour before dawn, thus avoiding the payment of mooring dues.





The question is whether you'll calibrate in traditional fathoms or EU metres.....

I am that sad sailor who has a lead line with those bits of callico and leather.

Its in metres and a slightly modified version, but I've stuck the references onto the board that the lead line is wound round and I varnished over the lot twenty five years ago... Its still going strong and gets occasional use.

 

[prv]

Polyester takes dye pretty well, I believe, and splicing the kind of very small braid usually used for lead lines will be fiddly. Why not paint each section with fabric dye instead? Much easier.

Pete

 

[vyv_cox]

My lead line has knots, one per metre up to five, then one every 5 metres. Assuming total darkness you don't need to be able to see them, they are easy to feel.

 

[LadyInBed]

I wouldn't bother putting markers at less than hull depth unless you are already aground and are trying to judge time to lift off

 

[lustyd]

The question is whether you'll calibrate in traditional fathoms or EU metres.....

How does an EU metre differ from the global standard looked after by the French? I assume by traditional you mean obsolete since there is now a very strong tradition of using ISO metres aboard boats.

 

[rob2]

I've always found splicing braid extremely difficult, although I'm told that brand new rope is easier as it's still slippery. I'd imagine, though, that you'll use more line to make the splices than to make the length! Personally I'd use three strand and short splices, as you don't need the strength of a long splice. The length of the splice will also have a mix of colours - perhaps you could use this to good effect as an extra level of graduation?

Rob.

 

[grumpy_o_g]

How does an EU metre differ from the global standard looked after by the French? I assume by traditional you mean obsolete since there is now a very strong tradition of using ISO metres aboard boats.

The French "standard" metre hasn't been a standard since 1960, when it was replaced by a suitably scientific definition of 1,650,763.73 wavelengths of the orange-red emission line in the electromagnetic spectrum of the krypton-86 atom in a vacuum. In 1983 the metre was re-defined as the distance travelled by light in a vacuum during a time interval of 1/299,792,458 of a second.

Although this could explain why I nearly ran aground last year I suspect it had a lot more to do with the fact that I glanced at the speed instead of the depth, thereby ensuring we accelerated onto the mud/shingle (actually I did run aground but we were able to reverse off so it doesn't count). Maybe I should stick to bits of string too.

 

[Wooden Boat Fittings]

Depending on how long you can get it, starter cord makes good leadline as it's strong and non-stretchy.

Instead of splicing or knotting the marks, you could try different-coloured twine to make short whippings at the appropriate locations, sewn through the line.

This is a 30' shoal-water line marked in metres for a client who wanted it to be able to be read by any of several amateur hands, during daylight. The client was a ranger in an aboriginal parks corporation in the NT --

The "lead" itself is a seven-pounder, in bronze as you can see.

And this is from an email to the client --

"The line is cored braided artificial non-stretch fibre.

The wrist-loop and thimble are both fastened with racking seizings in green twine that have been tested by dropping the weight in air for half the length of the line.

The markings were chosen for ease of use by laypeople -- one black binding for each metre up to four metres, a red binding at five metres, then a red and the appropriate number of black bindings for each metre up to nine metres. In addition, a narrow twist of black line has been added at each intervening half-metre. Each of these markings is not only bound to the line, it is also sewn through it to avoid slippage. The 'mark' at any point is the centre of the group."

And if you don't want the expense of buying a traditional lead, or a bronze substitute, you can always make your own lightweight version. See this link -- http://www.woodenboatfittings.com.au/public/leadline-home-made.pdf

Hope this helps.

Mike

 

[oldbilbo]

The French "standard" metre hasn't been a standard since 1960, when it was replaced by a suitably scientific definition of 1,650,763.73 wavelengths of the orange-red emission line in the electromagnetic spectrum of the krypton-86 atom in a vacuum. In 1983 the metre was re-defined as the distance travelled by light in a vacuum during a time interval of 1/299,792,458 of a second.

Although this could explain why I nearly ran aground last year I suspect it had a lot more to do with the fact that I glanced at the speed instead of the depth, thereby ensuring we accelerated onto the mud/shingle (actually I did run aground but we were able to reverse off so it doesn't count). Maybe I should stick to bits of string too.

Cooo, that's ever so esoteric! I'm very glad now I raised that particular hare....

As for running aground in places one shouldn't, howzabout right opposite the Royal Cornwall's terrace, when late on the tide and already late for lunch in their restaurant. 'Friend' on the helm passed the wrong side of one of those red sticky-up things, I didn't immediately notice, and we went from 5 metres to 0.5 metres, then 5 knots to 0.05 knots, in 0.005 of a second. I can still hear the laughter. Never lived it down. Never did it again. Never went hear there again.....

 

[LittleSister]

I would have thought that in a dinghy anything more than a couple of meters (1.0936133 fathoms for the traditionalists) was of little interest. A bamboo cane is probably the handiest gauge for that sort of depth - doesn't get in a tangle or bash your paintwork, and easy to store somwhere handy.

My leadline, bought years ago from a chandler, has no knots or bits of leather, but every metre has a stiff bit of cord (guess it's dipped in some sort of resin), and colour contrasted to the line. Easy enough to see or feel for the first few metres, but less handy if you wanted to check whether you were in 19 metres or 20.

We mainly use it to see which direction is shallowest once we've gone aground; or check whether the adequate depth we had when we started lowering the anchor has mysteriously disappeared (again!) now we've got the anchor dug in, 100ft of chain out, and snubber, anchor ball and light rigged!