archive – Diver TestsTEC UNIT MARES XR

IT’S NOT OFTEN THAT I GET the chance to dive with a twin-tank set-up nowadays. The usual location would be in UK waters, but over the past few years my ventures to the South Coast have been limited by short summer seasons, boat logistics, poor weather and overseas commitments.
So it was a breath of fresh air when I was able to take such a tec rig with me on a recent trip to Indonesia, and dive beyond the limits of single-tank scuba.

Mares is normally associated with recreational gear, but the Italian giant has recently produced a full technical range it calls “XR” (Extended Range).
This includes modular wings, backplates and harnesses, regulators and essential accessories.
I took advantage of Business-Class baggage allowances, packed everything I would need (and a lot of stuff I didn’t), and relocated the DIVER Test juggernaut to Bali for a few weeks.

The Regulators
XR regulators comprise two full-metal-bodied balanced diaphragm 25XR first stages and two DR second stages. The first stages are a mirror-image of each other except for the high-pressure ports, which are angled to send the hoses in exactly the same direction regardless of orientation.
Two medium-pressure ports on each first stage are angled downwards, and all three ports are positioned on the same side of each body.
The 25XRs are environmentally sealed with a dry coldwater kit, which keeps water, silt and contaminants out of the main spring chamber. The bodies are constructed from nickel-plated marine-grade brass and feature heat-exchange fins. They come only with a DIN tank connection.
The high-performance DR second stages are all-metal-bodied standard downstream models. Made of nickel and chrome-plated brass, they feature Mares’ own vortex design with a bypass tube and a metal-mesh front cover with central purge button. They are available in right-hand-side configuration only.
The Full Tec set tested comprised two 25XR first stages, two DR second stages, one short (56cm) and one long (210cm) mp hose plus a silicon neck bungee and a single small deadbolt snap-clip. It came in a zip-up regulator bag with foam inlays.

The Wing
I had been given an XR wing bladder in a horseshoe configuration, but doughnut-style bladders are also available for both twin- and single-tank configurations.
The wing bladder has 20kg lift capacity and is made of hardwearing 1200-denier ballistic nylon with a 600-denier polyester exterior.
The black polyurethane internal air-cell can be accessed through a semi-circular zipped opening in the front of the wing with a heavy-duty plastic long-toothed closure.
The wing inflator is centrally placed at the top of the bladder to avoid interfering with the first stages and aids for dumping air when in an upright position under water.
The “K-style” inflator has chrome-plated brass buttons adding a bit of heft to the end of the 35inch corrugated hose.
A single low-profile dump-valve is located at the left-hand base of the bladder, and has a knobless pull-cord. The wing is black, with silver-grey inserts and white embroidered Mares XR livery on each side-panel.

The Backplate & Harness
Mares offers a choice of two XR backplates: a heavy-duty stainless-steel model or the lighter aluminium version I had on test. The latter is made from 6061 marine-grade anodised aluminium alloy and coloured graphite black.
Both backplates are laser-cut with 13 etched slots. Eight of these are to optimise positioning of the harness webbing, and there are four additional slots to take twin cam-bands for single-cylinder attachment, and a single 2in-wide crotch-strap slot.
Three holes down the centre of the spine allow for direct steel-banded twin-tank connection via a threaded rod and wingnuts, and a lower vertical slot provides lateral adjustment for misaligned band bolts and the wing bladder.
Further holes around the periphery allow accessories or the maker’s sidemount butt-plate to be attached. The steel and aluminium backplates are identical in size and profile and have laser-cut XR logos. The bare aluminium version weighs in at 750g.
The backplate was delivered with the harness factory-threaded, so required a simple adjustment. The harness uses 3.5m of logo-embroidered webbing, and the shoulder sections have no break-points.
There are two bent and two straight black aluminium D-rings, locked in place by aluminium bar slide buckles. The two buckles on the shoulder sections have smooth slots, and the two on the waist-belt have toothed slots to prevent the lower D-rings slipping when sidemount stage-tanks are attached.
A standard weightbelt buckle is fitted on the belt’s left side. A separate webbing crotch-strap with a fixed front loop is attached to the lower slot on the backplate, and comes in a 1.5m length with front and rear D-rings for scooter or ancillary equipment attachment.
Elasticated retainers act to stop loose ends of the webbing flapping about.

The Ancillaries
Mares supplied an all-metal submersible pressure gauge (SPG) with a short 56cm high-pressure hose.
The gauge body features a double-chrome mirror-plated brass housing with a tempered glass screen and a reliable copper-beryllium Bourdon tube mechanism, said to be the preferred design of instrument for DIR divers.

I spent a few hours Facetiming my contacts in Bali, trying to locate a twin-tank set-up suitable for use on this test. The wing bladder wasn’t fitted with camband slots, so the only way I could get it to work was in tandem with steel-banded twin tanks which, I was told, were rarer than hen’s teeth on the island.
My old friend, expat Paul “Jockeyboy” Stephens, came to the rescue and undertook a six-hour drive to deliver his own twin 12-litre tank package to my guest villa before my arrival.
He also supplied a Custom Divers quick-release mounting system for attaching the wing and backplate to the twin-tank set.
Thank you, Jockeyboy, I owe you one.
The ethos of the Mares XR range is to provide dive-rigs for extended-range diving in line with the DIR training philosophy.
If you’re not familiar with “Doing it Right”, or the Hogarthian way, it is “to eliminate the unnecessary while configuring the necessary in the most streamlined way possible. Simplicity and efficiency is the key. If you don’t need it, don’t take it.”
With this in mind, I configured the first and second stages to deliver both short and long second-stage mp hoses behind the rear of the wing, both emerging on my right-hand side.
The short-hose second stage ran from the right-hand first stage and was fitted with the supplied silicon neck bungee.
The 2.1m hose was supplied from the left-side first stage and fitted with the small bolt-snap to clip it off on a shoulder D-ring when not in use.
The mp hose supplying the wing inflator was run diagonally from the right-hand first stage and the hp hose and the gauge from the left. This probably sounds complicated but, in the world of twin-tank, twin-regulator set-ups it doesn’t get any simpler.

Under Water
The XR25 and DR regulator combination was a delight to use. Breathing was smooth and natural, with very little cracking effort needed when starting to inhale (a characteristic of the very top regulators).
The second stages were slightly negative in the water, which caused them to droop a little and end with the exhaust port resting against my chin. In fact this became an advantage, because I didn’t need to bite down hard on the soft silicon mouthpiece to keep everything in place.
The large, centrally placed purge button was easy to access, and delivered gas in a progressive manner.
The wing was large, and when fully inflated at the surface provided more than enough lift to pull my head and shoulders clear of the water, even wearing the heavy steel twin tanks.
As with most back-inflation air-cells, this one tended to push me face-first into the water, but I soon realised that by releasing a bit of gas it would behave differently and hold me upright and steady while still keeping my head above the surface.
Under water the lack of compression bungee straps became evident, with the bladder tending to flap around under my arms when completely deflated.
With only two dump-valves on the wing this forced me to twist and contort my body to get into a position to dump gas.
The lack of a second kidney dump on the bottom of the right horseshoe didn’t help, and left me wishing I’d opted for the doughnut-bladder version.
The minimalist harness system was amazing. Once adjusted to my size and profile it was easy to slip into, and held its heavy payload securely in place.
The lack of padding on both the shoulder-straps and backplate wasn’t an issue, even when wearing a 3mm wetsuit. The crotch-strap proved essential to stop the unit rising up my back, and seemed to tie the whole thing in place.
D-ring placement was excellent and gave me ideal locations to place my DSMB and reel plus a primary torch.
The SPG sat neatly by my side, clipped off to a waist-mounted D-ring. Its weight kept it in place and it was easy to access. The shorter-than-usual hose helped to streamline the rig.
The silicon neck-strap was possibly the best I’ve ever used, keeping the secondary reg firmly in place without it flopping about and becoming a nuisance.

It’s a wonderful feeling being the only diver with 24 litres of gas at his disposal on any given dive. My buddies and guides had single-tank set-ups, and were rightly getting a little edgy after 80- or 90-minute immersions while watching me settle on another photo subject.
There were a few annoyances with the wing. The lack of a pull-dump at the top of the inflator hose and a secondary dump at the right kidney required wriggling to expel gas from the cell, and the absence of compression straps caused it to flap about a bit.
The rest of it was a joy. This is a high-quality set-up built to impressive standards and designed for the tried and tested Hogarthian configuration, and it did its job very well. Kudos to Mares – its journey into the world of extended-range diving seems to have got off to a great start.

PRICES: 25XR with DR full tec set £730. Aluminium backplate & harness £174.
20kg twin-tank wing bladder £228
FIRST STAGES: 25XR, balanced diaphragm, left- & right-handed. environmentally sealed
PORTS: 2 mp, 1 hp
SECOND STAGES: DR all-metal body, mesh grid cover, standard downstream valve
MP HOSES: Primary reg 210cm. Secondary reg 56cm
BUOYANCY CELL: Horseshoe, twin-tank wing bladder
BACKPLATE: Laser-cut 6061 marine-grade anodised aluminium
HARNESS: “Heavy Light”
D-RINGS: Six black aluminium with bar slides
CONTACT: www.mares.com
WING 7/10

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Appeared in DIVER September 2016



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