New flies

Weather has finally moved into warm water mode.

Three new flies made from the scraps to float close to the surface and disturb it on the retrieve. The first shown is just a single hook. The other two have a small flying treble.

The last one in the sequence was the first of the batch. The top one was manufactured next. The middle one was the last and came out the best. The white thread is very friable and I need to get a stronger variety.

New Moon at Mangaf

Low tide. Nearly a full spring tide.
Weather:  High of 30^oC low of 19^oC, Sunny, Wind 8kph from SSW.  Sea calm.
New Moon (0%).  Oct 24 2014.
Sun rise 0554 Sunset 1709
Moon rise 0609 Moon set 1736
Fishing prediction from "Fishing Times Lite v1.2" app for iPhone was "Good".
Low tide 0540 (0.6m)  High tide 1210 (2.3m)  Low tide 1730 (1.1m)  High tide 2340 (2.7m).
MLWN 1.5m  MHWN 2.2m  MLWS 0.6m MHWS 2.7m.  Full Spring tide due 25th Oct.

Tidal data  for Mina Al Ahmadi : 29^o04.0'N 048^o10'E from "Tide Planner v4.3" app for iPhone.

Views at low tide after last week's rough seas.

1. Looking North

2. Underwater obstacles

3. Looking East to Fahaheel Sea Club marina entrance 

4. Rocky outcrops

5. Underwater obstacles

6. Rocky outcrops

7. Old Coast Guard vessel

From 6 a.m. to 7 a.m. the water was quite busy with needle fish and half beaks chasing the boobies, though not actually greeting the hook points attached on their bony mouths / "beaks". Switching to a white sparkly fly in this water of 1m depth, I then tempted this short-fin goatfish on to the line.

Short-Fin Goatfish (Upeneus oligospilus Lachner, 1954), 

with a 10g lead weight for comparison

Not having caught one of these before, I went to www.fishbase.us to find out what it was, from the Kuwait list of fish species. It turned out to be easy to ID with its bright yellow barbels.

Physics and Fly Fishing.

Objects moving in a fluid generate friction between the fluid and the object’s surface.  This viscous drag can be calculated using Stoke’s Law for a spherical object.

F = 6ph r v

Where F is the viscous drag measured in newtons (N), h (eta) is the viscosity of the fluid in newton seconds per metre squared (Nsm^-2), r is the radius of the object in metres (m), and v is the velocity of the object in metres per second (ms^-1).

This all got me thinking.  Temperature affects the viscosity of water.  In the winter the water will be more viscous than the hot summer months, especially in a shallow lowland lake or pond.  Flies will sink faster and be dragged through the water faster.  Now I understand that Stoke’s Law is for spherical objects and would only really apply to an “egg” fly but he principle will be still applicable to the other shaped flies as well as the fish, which will also be able to move through water at a faster speed in the summer months.

In salt water, the effect will be heightened, especially in tropical saltwater flats where in the summer months the salinity will increase further.  Do we adjust our fly fishing retrieve speed and counting for sinking to depth for the temperature?  Even within the water column the temperature will vary with depth. In the winter and summer there are temperature zones as their densities vary.  In the spring and autumn the mixing occurs in the water column and the zones disappear as everything gets stirred up.

I am aware that in NE England floating flies attached to sinking lies are prohibited and other flies have lead and brass (gold) head beads etc. added to allow rapid sinking.  That would imply that flies available are either floating or sinking.  With a floating fly and a floating line everything seems simple enough.  When adding in a sinking line you can buy slow sinking, medium sinking or fast sinking casting lines.  That is to say, they are all negatively buoyant.  In winter and summer however, they will be in different temperature water and therefore different density water so with sink at different rates.  Your fly will sink because it has a metal hook and may have lead or copper wire added or a metal head bead. 

Why are all hooks (that I’ve ever seen) made of metal?  Why not ceramic, or hard, clear plastic?  Does anyone make a neutrally buoyant fly that stays at the depth the sinking line drops to and goes no further?  With a floating line it could hover just below the surface.  With a sinking one it would not drop straight to the bottom and could be working its way down slowly with the line.  I don’t suppose for one minute that a dead insect or fish hurtles through the water to the bottom. They drift down slowly.

Is it about time the manufacturers redesigned the hook and fly for its position in the water column?