Manual depth finder

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APS

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In case my electronic Depth Sounder doesn’t function, is there a ‘marine’ plumb line I can buy or, at a push, any suggestions re how to make one to check depth in shallower waters?
 
For £25 plus postage and packaging I can supply a brick and a length of line up to 10 fathoms. Greater that 10 fathoms its £65.
 
Got the message & it’s clearly time to end the thread. On a serious note we used one a long time ago on coastal passage harbours & we certainly hadn’t made it ourselves so I just thought that there might be something for mariners not in possession of lumps of metal - probably a basic decorator’s will do the job.
 
I started saving the lead tops from wine bottles to make a lead, until my wife started chucking them away, and then they started using tinfoil and I gave up.

You might find the odd church roof still available.
 
For a quick indication, I use a length of line (about 10m) with a short piece of lead pipe on the end. Different colour corks are attached at 1.5m (boat's draft), 2m, 3m and 4m. This has helped to find the way through some shallow patches.

The trick is to have a loop round your wrist, then throw the weight out in the direction you want to find the depth. Noting the colours not floating gives a quick indication of depth in that direction.
 
When it was my only depth sounder I used a lump of lead maybe about a pound weight with a length of sash cord with various carefully whipped marking tags. Now occasionally I use an old heavy shackle with a bit of string just to check the electronic sounder offset and accuracy.

Actually sailing with just a leadline makes you much more careful: the first accidental grounding I had was shortly after fitting an early Seafarer II spinning-neon sounder - it let me cut corners that I wouldn't have dared otherwise.
 
But whatever you make or buy, use it and practice with it. Don't just keep it aboard for 'one day'. I got to grips with our leadline from our mooring one unsailable afternoon.

I've found that stretch free rope makes the world of difference as you can then 'feel' the weight contacting the sea bed, assuming that it's relatively firm. Otherwise it is relatively vague, especially if you or the water are moving at faster than a couple of knots.

And doing the RTI a few years ago I saw most of the Folkboat fleet using thin bamboo poles of about 7' long to sound out the bottom at Ryde Sands before going about. Anything to keep out of the head-on tide.
 
When I raced my RHOD depth sounders were not allowed, a bamboo pole with a lead weight taped at the bottom end worked very well. It had 1ft of red tape starting from 3ft, our draft, then 1ft of green tape. So the crew wielding the pole only had to say useful things such as “top of the green”, “middle of the red”, etc. Another useful indicator was the pitch of the voice which increased in inverse proportion to the depth��
 
I've raced on boats where electronics were not allowed. A 'dipping cane' is good.
With a lead line, there is a reason that a proper one is much heavier than a screwfix plumb bob. It needs to sink fast and overcome the drag of the line through the water.
It needs to hit the bottom before you overtake it!
If you go lightweight on the lead, you'll want very thin line on it, if you want to use it while moving rather than just to check the sounder in still water.
 
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