Most fish are not stupid and a lot of them are pretty clever, especially if they have been caught before.
Your aim as an angler is to make the hook bait look natural, like the loosefeed you are feeding.
Unless you do it properly, youТre not going to catch anything and unless you know the depth of your swim youТve got no chance. Plumbing your swim is absolutely vital and is something you must do before you bait a hook on any venue.
With pole fishing itТs really easy too, just a case of adding a weight heavy enough to sink the float youТre using and lowering it down slowly on a tight line.
With hooks of a decent gauge wire like B611s I prefer the bell-shaped plummets with the cork in the bottom. These can bend fine wire hooks like B511s though, and with these I prefer the ones your hook sits into, or for muddy bottoms the ones with the large, flat, brass base.
You are not just plumbing one convenient area in front of you though I'm afraid.
You should plumb at all distances out from you, and also to the right and the left, to build up an underwater picture of the bottom.
You are looking to see where any ledges are, if there are any holes, how quickly the bottom slopes away etc, and only then can you decide where to fish.
If bream are your target, for instance, you need to find a flat bit, as bream will only feed comfortably on flat areas. If the flat area is at 12 metres, IТm afraid thatТs where you will have to bait up and fish.
Roach, on the other hand, will feed on slopes happily, although donТt forget groundbait will roll down slopes and this can take the fish out of range.
I recall one world championship on a rocky venue in Finland where the French blitzed the field.
The bottom was like a sloping, snaggy reef, and a nightmare, but they worked out that if you could find a one foot square flat bit of rock, and groundbait onto that, you could catch roach just off bottom.
No-one else caught roach in any numbers, because no-one else had worked out how to be just off bottom all the time.
That taught me a lesson about plumbing and if it takes you 20 minutes, thatТs fine. Having a clear picture in your head of what the venue is like under water is vital.
The actual process of building the picture up is easy. With the rig set overdepth you will feel the СbumpТ as the plummet hits the bottom. You can then hold it there for a second to gauge how far over depth you are and then move it away from you, to the side, etc as you build the picture up.
If you find a sudden ledge, even if itТs a drop of only three inches, this will be a natural fish-holding area as it will be a Сswimming lineТ parallel to the bank that the fish naturally follow.
Fishing just beyond it can produce great results when all around you are struggling, and if I find a ledge I like to mark where it is on the butt of the pole where my thumb will sit.
If you find a steep drop off... bingo! Bait this accurately and you should catch just beyond it.
When you've decided where to fish, you should always set the float to the exact depth to start with, even if you plan to fish overdepth or off the deck.
Once youТve got it exactly right, with the plummet resting on the bottom and only the very float tip is showing, bring the rig in, noting how far out you are fishing by looking at the butt section.
Un-ship so the rig swings to hand and tuck the hook into the bottom section so the rig sits tight to the pole, and mark where the pole float sits on the pole with Tippex.
I prefer to mark the top and bottom of the float.
The Tippex scrapes off easily at the end of the session with your thumbnail without damaging your carbon.
If you are fishing with more than one top kit, you absolutely must plumb each rig up separately.
Lining one section up against another on the bank and putting all the floats the same distance from the bottom of the section will not work, because different elastics will stretch the high tech line by different amounts when placed under tension.
All you have to do now is set the depth for fishing. Normally for bream, tench and carp youТll be better off starting a few inches overdepth, while for roach, position your hook so it sits a couple of inches off the dead depth.
Gareth Purnell, Improve Your Coarse Fishing

1. Flat based plummets
Flat based plummets are ideal for those venues having silty bottoms, and very unlikley to come off due to the silicone tubing which secures them.

2. Stonfo plummets
These are fast and ideal with bloodworm because you plumb up an inch off deck. But I've had trouble with them falling off with small, finer wire hooks.