Most are around 8-10cm in length, but some species can grown to 40-50cm. They’re not dangerous, but if you pick one up, mind the mouth - they have a particularly nasty pair of jaws that can bite you.
I’m generally opposed to two hooks on a fly, but in the case of the rag worm imitations, it really makes sense. The worms are slow and have absolutely no defence against a sea trout, so sea trout really don’t hit them hard, and it seems they have no preference to hit the head, as they often do on for instance sand eels.
On the fly, they are hooked on the trailing hook as often as they are on the front hook. I’ve made a bit of an experiment this year. I’ve incorporated a little flash in the dubbing loop on the front hook. The purpose is to see if I can bias the sea trout to the front hook this way.
This imitation is an amalgamation of The One Worm and my own Fur Worm. The One Worm is usually tied with marabou - I use rabbit for these, and on smaller imitations, I use mink. Later today I’ll try thin strips of kangaroo that I just found in a box - it looks good.
I tie them both weighted (with a tungsten bead on the front hook) and un-weighted. Un-weighted are important, I think, because often the worms (and the sea trout) are as likely to be in 20cm of water as they are in 1m of water. You *can* just fish the weighted ones faster, and that works well, but I do like to try and imitate the natural behaviour of the worms.
The un-weighted ones in particular can be a bit hard to sink, and if you falsecast to many times, it’s dry enough to float for the first 2-3 strips. The un-weighted I fish in low water, and often to spotted fish, so casts are not that long usually, so it’s not a big problem. When I’m done tying the flies, I place them in a bowl with warm water and washing up liquid and simply wash them to get of any natural oils that might remain in hairs, and that seems to help a little.
Weighted or un-weighted, do throw a dry one out there - it’ll float forever. Stick the fly in the water and squeeze out all the air and make sure its thoroughly wet.
Tied entirely of rabbit fur (on soft spinning line) the fly is incredibly mobile and is never completely at rest. Even when left alone it’ll pulsate, making it a very good fly. My friend, Daniel Holm, has made a movie on the tying technique - he uses marabou dubbing, but the basic technique is the same. You can find the movie here. I tie mine using Ahrex NS 172 Gammarus hooks (#10-12 for the rear hook, #4-6 for the front hook).
This is one can of worms I *will* be opening very soon.
Have a great weekend! Lars