Source: www.matweb.com

Internally we use an aluminium motor compartment, all stainless fasteners, copper alloys for the electrical studs and HDPE and clear unbreakable polycarbonate bulkheads.

What batteries are used, and where can replacements be purchased?

We use only Genesis batteries, the best scooter should only use the best batteries! Genesis batteries, in the 26 and 42 a/h sizes, significantly outperform other batteries of the same size and weight.

In fact, the Genesis 26 A/h has the same burn time as the Powersonic 33A/h battery, for less weight and scooter size.

Other advantages of the Genesis, longer life (2-10 years), greater cycle life, deep discharge recovery, and the possibility of faster charging times. With the Interacter 5 Amp charger, recharge times are approximately 3 hours for the UV-18, 5 hours for the UV-26 and 9 hours for the UV-42.

Replacement batteries are available:
Set of 2 batteries for UV-18, G16-EP
Set of 2 batteries for UV-26, G26-EP
Set of 2 batteries for UV-42, G42-EP

***note G42-EP batteries can replace Yuasa NP-38-12B batteries
as used on UV-38 model***

What is the UV depth rating?

UV scooters are now rated to 120m /400 feet. 1 UV-18 has been dived more than 9 times to sub-500 feet, including 1 dive to 616 feet.

HDPE hull vs PVC hull?

PVC industrial pipe is fairly impact resistant, however HDPE pipe is virtually indestructible, including freezing temperatures. Industrial PVC pipe has a working temp of 33 to 140F,
below 33F it becomes brittle. HDPE (as used in the UV scooters) has a brittleness temperature of <-100F (-78C)

What about crush depth, PVC vs HDPE?

The crush strength of a pipe exposed to external pressure decreases as the distance between bulkheads increases. As a rule of thumb, the ideal bulkhead spacing is 1 diameter.

At a distance of 10 diameters, the bulkheads offer little to no added strength. Luckily, the bulkheads in the UV scooters also act as battery supports, and the battery length is less than 1 diameter, hence we have a near ideal bulkhead spacing.

Submerge rates the UV scooters to 120 meters/400 feet. Facts: To this date, the deepest known use has been 170 meters or 560 feet. Also, a UV-26 has been left as a safety scooter in a cave for 5 days at 120 meters/400 feet without incident.

The calculations below must be approached with caution. They can not be used to calculate the exact crush depth. These formulas were used as a basis of comparison between different available pipe materials and thicknesses.

The goal was to select a HDPE pipe which was at least as likely to withstand 500 feet as PVC 10" Sch 40 pipe, which is known from actual dives to tolerate 500 feet.

These calculations have been confirmed and proven by real dives.

Primarily, we chose HDPE over PVC due to it's superior impact resistance, especially in freezing temperatures, black color so that scratches would not show, and to differenciate the Submerge UV scooter from the competion. We lead, not follow.

		UV scooter
	PVC 10" Sch 40	HDPE
Diameter	10.75"	10.75"
Min wall thickness	0.375"	0.632"
Poisons Ratio	0.33	0.4
Modulus of Elasticity, psi	200,000	119,000
Weight, lb/f	7.5	8.5
Brittleness temp, celcius	approx 0	<minus 78 C
When burned, smoke is:	toxic	less toxic
Ullta violet light rating	titanium/good	carbon/good
Crush depth, Roark	544 feet	1055 feet
Crush depth, Flugge	135 feet	504 feet

According to Roark, FORMULAS FOR STRESS AND STRAIN, 1961
According to Flugge, HANDBOOK OF ENGINEERING MECHANICS, 1962

Notes:

We used 0.625" in the calculations for the HDPE hull thickness.

For distance between bulkheads, we used 8" for both materials.

Above program taken from a website from "P-Subs", no longer active or we would have given a credit/link.

HDPE = High density Polyethylene.

The Mako motor has an aluminum tail cone with captured o-rings, and this mates to the flexible plastic aft end cap of the scooter.

To minimise the possibility of the plastic flexing in this area, the UV scooters have an aluminium motor compartment, which extends down into the endcap close to the motor seal, adding an enormous amount of rigidity to those o-ring surfaces. The motor compartment itself seals the batteries from the motor with double o-rings, and has a back up system (hydrogen catalyst) to deal with any internal gas leaks in the scooter.

How fast is the UV compared to other scooters?

Only some aquazepp scooters are significantly faster than UV scooters. UV scooters use a custom wound Oceanic Mako motor, which significantly improves performance. Speed up to 200 ft/min for a diver with double 104's and 2 stages is fast, and this pace can be kept for long periods due to relatively low current draw.

More importantly than speed, the design of the Tekna/Mako motor is very efficient, providing torque at relatively low RPM's which eliminates the need for gear reduction drives.

Are the people at Submerge UV scooter divers?

Absolutely! Rodney and Suzie dive both wreck/open water and in Florida caves.



Husband and wife dive team Rodney Nairne and Suzie Dudas, owners of Submerge Inc.

To whom is the engineering credit for the UV scooters due?

Without a doubt, the original design team on the Tekna scooter, circa approx 1984, deserves all the credit for a brilliant thruster design. The kort nozzle and hydrofoil propellers, variable pitch speed control, low rpm/high torque motor and simple circuitry, were all part of the original design which is used to this day in Oceanic Mako scooters, as well as the deeper rated Submerge scooters.

I was obviously influenced in the design of the Submerge scooter by the renowned Gavin scooter, however I made many changes which have over the years been widely accepted as significant improvements to the state of the art.

In particular, the tapered back end, milled out shroud support arrangement, ridgid aluminium motor compartment and the ergonomic and simple handle come to mind. Some of which have been "adopted" by the seller of the Gavin scooters.

How should I configure my equipment to get the best performance out of a UV scooter?

More than any other factor, your speed through the water and your enjoyment of the dive will be enhanced if you configure your equipment in a streamlined manner.

Submerge recommends a Hogarthian configuration for double cylinder diving. Hogarthian is named after Bill Hogarth Main, who is one of the most respected Florida cave divers. His equipment has remained virtually unchanged for 28 years! It should be noted that Bill himself did not design or develop most of the equipment and techniques, but adopted the ones that worked.

The Hogarthian configuration is not "static" and will continue to evolve as new techniques are developed and proven. An example is stage scooter diving techniques and gas management first used by the dive team of

Bill Main and Bill Gavin, and since developed to acheive unprecedented distances by the WKPP, and in the last few years Hogarthian has been used to form the backbone of the "DIR" marketing system.

The system consists of Manifolded 104 steel cylinders, backplate and harness, canister light on the right waist. Only 3 D-rings. Aluminum only stage cylinders all on the left side. More than anything it is so simple it seems he is missing a bunch of gear when you see him in the water. With this system and a 1/4 century of experience, Bill and his dive buddies often swim further than most divers can manage with a scooter!

The Hogarthian philosophy could be summarised with "keep it simple". Another description would be it is minimalist. It you don't absolutely need it, don't carry it. In an emergency, poorly configured and
extraneous equipment can become a liability. Solo diving is accepted but not recommended, and a buddy team should such that your buddy is your backup and bailout gas.

Here are some key points related to streamlining for scootering:

* Eliminate all "danglies". Anything hanging into the prop wash will slow you down.

* A canister light is preferred, with a palm mounted light head held in the left hand. (The right hand operates the trigger). This allows you to point the light in any direction. Logically, depth gauge/bottom timers/compasses should be on the right forearm so that they can be checked with the light in the left hand, without lifting the trigger.

* Submerge recommends a harness and backplate for scooter diving, as the backplate provides an excellent, stable attachment for the crotch strap, which is what actually pulls you through the water. Look for back plates with a crotch strap slot which can accommodate 2 "webbing, which is more comfortable than the 1."

* If you find a harness difficult to don/doff, try loosening the shoulder straps. If you still have have difficulty, before you switch to a soft pack BC, try a clip under the left shoulder D-ring.

* Keep the scooter in front of you as far as possible for best speed. Don't be "on top" of the scooter. Your right arm should be almost fully outstretched.

The most streamlined BC's seem to be the simple wings style (No Bungy on the wings unless you just can't live without it ;), these "classic" wings have been made for years by Diverite, and are now also offered by OMS and Halcyon.

Rebreathers: No common configuration has emerged from the dozens of possible configurations. The best advice is keep it as simple as possible, avoid danglies, and figure a way to check your P02 without
waving your light about (very distracting to other divers, and a big no-no in cave diving!)

You should also be able to check your P02 on the fly, ie without stopping the scooter. Ideally you will have your PP02 readouts on your right forearm so you can shine your light on them while scootering with the right hand.