The Phreatic Zone

This excellent article was written by Paul Larrett (Cave 2, Tech 2) back in 2001 and well worth digesting!

REGULATOR ADVICE.pdf

When I was playing about with weigthing and trim a while back, I came up with the idea of an adjustable tailweight….This was ideal for finding out my exact CoG (Centre of Gravity) when trying to hone my horizontal trim and to balance my rig.

To counter head down/floaty feet

Mid position

To counter head up/feet down

 The best way to find your correct weighting is to get down to say 30bar and strart stripping weight, piece by piece from your weight belt and hand it to you buddy.

 Once you find the weight that is right for you…..get moulding your weight and if your going to use the wifes soup pot…buy a replacement quickly!

 *When melting lead, use protective equipment in a well ventilated area!

Having seen one of these bad boys in action on Cave 1, this was my first close look….and first impressions were good!

They have a more robust feel than that of the Halcyon Scout or scout copies i.e Photon or Solaris with the added security of a 2nd O-Ring, deeply knurled handle and a heat dissipation tube inside.

Out of the box
Instructions, spare O-Rings and catalyst pellets for NiMh cells

Stipped down

Side By Side with the Scout

Colour temperature comparisons, Heser on left

And again, Heser on left

Beam Pattern taken from 10M, Heser on right

Unfortuantely I do not have any footage of the heser versus rivals underwater, but I can assure you of one thing…..There really is no comparison for burntime, beam and colour temperature!!

The Halcyon Scout LED upgrade will cost you £88 each, added to the £59 for the standard scout which weights in at a hefty £147 per backup!

The heser is £110 to your door through Jack@dublinbaydiving.com

Click the picture to view the website

AGIR wings are the first wings designed specifically for European (e.g. Faber) double cylinders. They have the lift capacity of 38lbs / 17,3kg and 56lbs / 26kg. They are designed for use with medium- to heavyweight doubles together with aluminium deco cylinders and “common divegear”.

habrok- has fast become popular among divers (not just techdivers), who want comfortable and perfect trim both swimming and / or on deco. The design itself gives great stability, and prevents front tip over.

Additional advantages:

Short zip, not one inch more than necessary. A zip is a weak point, so it´s minimal.

Room enough for the backplate. It will not be squeezed to the cylinders.

Several holes for finding the right trim.

Rubber protection under the zip to avoid impact damages.

Cover made of nylon coated cordura

Innerbladder of strong 420 denier “puncturesafe” cordura lifejacket fabric.

Thicker cord to dumpvalve for easy grip.

The OPRV (dump) is placed to give best performance,
then used get the right leveltrim.

Price: €460/£315

Click the picture to view the website

salvo nimh 21 watt hid 9 Amp NIMH Battery Providing 240 Mins.(+/-5%)of Burntime
21 Watt HID with 1500 Lumen Output @ 6500 Kelvin
-New Dry Lid is completely sealed to prevent water intrusion due to cut cord or switch boot.
Dry Weight 7 lbs.(3.2kg) 3 lbs(1.36 kg) Negitive
Recharge Time from Complete Discharge 5 hours
Universal Input Charger. US Input Cord Provided, UK and
European Input Cord Available.
Canister and Head Machined from Solid Rod Delrin
10.75″(272mm) Length, 2.75″(69mm) Diameter

Price: €1100/£750

Click the picture to view the website

Powered by a 7.2 Amp 14.8 Volt Li-Ion Battery providing 4.5 hours of burntime.
Each battery contains electronics to ensure proper charge, discharge and short circuit protection.
New Dry Lid prevents water intrusion into canister due to cord or switch boot damage because it is completely sealed.
21 Watt HID is Focusable with 1500 lumen output at 6500 kelvin.
Dry weight of 5.2 lbs.(2.35 kg.) 2 lbs. (900 g.) negative.
Canister is 8.75″(22.2cm) height and 2.75″(7 cm) Dia.
Li-Ion Charger is universal input 90 to 240 volt, 50 to 60 hz.
European and UK input cords available.

Price: €1200/£825

Click the picture to view the website

Price: €1100/£750

Datasheet:  HID_Lugh_9Ah_1.PDF

 

Obviously a curve of some sort that drops down instead of going over the shroud would be a better…

Relay Modification

I decided to make a slight modification to the standard relay board to make it modular!

The relay conversion basically substitutes a 30A poor quality relay soldered to a custom board with a plug-in 60A relay.

When running on full load (diver with stages, dry suit etc. at full pitch) the motor will draw around 16-18A. If something gets stuck in the prop, even for a fraction of a second that peak current will increase to 40, 60 or 100A (who know’s?), what happens then is the clutch slips (if everything is set up correctly).

All this happens in a fraction of a second. That peak current is enough to weld the contacts closed on the poor quality 30A relay.

Trouble is, to replace it means un-soldering it from the board or replacing the whole board, hence the modification to a modular relay!

The standard relay is soldered to a PCB

UK Relay Mod

Batteries

In the UK the batteries you want is the Powersonic PS12180 (12v 18aH) which is wired in paralell to give you 24vdc, weighing in at 6Kg each, available here http://www.batterymasters.co.uk/proddetails.asp?ID=384&Department=SLA amongst other places!

PS12180

Power-Sonic Rechargeable Lead-Acid Battery, PS-12180 *12 volts (6 cells in a series) *Nominal Capacity 20 hour rate (900mA to 10.50volts) is 18.0 A.H. *Dimensions: 180 (L) x 76 (w) x 167mm (H)

PS12170

Power-Sonic 12 Volt, 18.0 Amp. Hrs. rechargeable SLA Battery PS12170 is air transport approved, and meets all current requirements set forth by the D.O.T., I.A.T.A., F.A.A., and C.A.B. U.L. recognises model PS-12170 under file number MH 14328 PRICED PER BATTERY Dimensions: L181mm x W76mm x H167mm (height over terminal 167mm) Weight 6.00

I have been reliably informed that the PS12170 is the same battery only without the flame retardent casing required for mod/industry applications, although the only datasheet I can find states that it is a 17aH battery!!

The price difference is negligable to be honest!

Burn-Tester

You need a 2 x 300W, 3Ohm resistors wired in paralell to give you a resitance of 1.5Ohm. I found the part numbers from RS Components http://rswww.com/cgi-bin/bv/rswww/home.do?cacheID=ukie

These are the resistors you want:-

OHMITE C300K3R1 3.1ohm 300W 040g

RS Stock no: 2508382142 Manufacturer: Ohmite Part no: C300K3R1 £16.19 each