Tips for Buying a Dive Computer

Do you dive with Nitrox?

If there's even the slightest chance of you using nitrox, or wanting to in the future, then it makes sense to buy a dive computer that supports nitrox diving. Generally, these dive computers only cost a little more, and buying one that can match your pace as you advance through your training and diving experiences will prove cheaper in the long run.

Do you want to show your cylinder contents?

Air-integrated dive computers monitor how much gas you have remaining during a dive, and your breathing rate. They will tell you how much time you have left at a given depth (whether that's limited by your remaining air, or your dive time). The dive computer can also work out, if you're breathing slow, that you've absorbed less nitrogen and therefore can permit you to stay down longer. Longer dives - what's not to love?

Wrist or Console?

Generally this is a matter of preference. Bear in mind that if you choose a console computer and don't plan on taking your regs on your next dive trip, you'll either need to hire and use a dive computer you might be unfamiliar with, or take the dive computer console off of your regs and put it on the hire regs. Some people go for the 'big watch' style dive computers and wear them every day. Our preference, especially for technical and cave diving, is for a large, easy to read wrist mounted dive computer.

Safety Tip

Time-to-fly is the time you must wait between your last dive and ascending to altitude. Most dive computers display the amount of time remaining until residual nitrogen levels drop to the point where the computer considers a subsequent dive to be the same as a non-repetitive dive. This time may be described as a time-to-fly. However, even after considerable study, flying after diving recommendations remain controversial and continue to evolve. Decompression sickness statistics from Divers Alert Network (DAN) make it very clear that no current decompression theory and computer algorithm is able to account for all the complexities of decompression introduced by flying after diving. Instead, we encourage you to follow the May 2002 Flying After Diving Workshop recommendations published by DAN:

For a single no-stop-required dive, a minimum preflight surface interval of at least 12 hours is suggested.

For multiple dives in a single day, or multiple days of diving, a minimum preflight surface interval of at least 18 hours is suggested.

Wait substantially longer (i.e., 24 to 36 hours) if you have done any decompression-stop-required diving.

Portland Bay Reef

Reef Dive | Boat access

Depth: 10 m (33 ft) to 15 m (49 ft)

Level: Open Water and beyond.

Portland Bay Reef (aka Corkscrew Reef) lies off the end of the "corkscrew" in Portland Bay (aka Henty Bay) on Victoria's Discovery Coast.

The original 'Corkscrew' was built as a gift to the Portland Harbour Trust in 1960 by the contractors who constructed the port. It had an observation deck approximately 10 metres above sea level. It was replaced in 2018 as the original structure was unsafe and in dange of collapse.

Diving Portland Bay Reef

Corkscrew, Portland
Source: Portland Tourist Association

Portland Bay Reef rises from 15 to 10 metres deep and is roughly circular in shape. Weedy Seadragons and Crayfish can be seen as well as a variety of fish. A very nice area for photography.

Location: Portland, Victoria 3305

Safety First: Portland Bay Reef is just outside the Portland Harbour entrance. Check for shipping movements before anchoring here. Best to keep the boat live.

Best dived in good conditions with a low swell. See WillyWeather (Portland Harbour) as a guide for the tide times and the height of the tide.

Portland Bay Reef can be accessed by boat from the Portland Harbour, Lee Breakwater Road North Ramp or the Portland Harbour, Lee Breakwater Road South Ramp.

Finding the Portland Bay Reef

We are not very confident that the GPS mark we have for Portland Bay Reef is accurate. If anyone has an accurate mark, please pass it on to us.

Divers have the opportunity to catch Southern Rock Lobster (aka Crayfish) at this dive site. Remember your catch bag, current Victorian Recreational Fishing Licence, rock lobster measure, and cray tags. Once you get back to the dive boat, or shore, make sure you clip the tail and tag your Crayfish as per Fisheries requirements. Please abide by all current fishing regulations if you intend to catch crays. See article-catching-crayfish for practical cray hunting advice from The Scuba Doctor, plus melbourne-cray-dives for a list of other crayfish dive sites near Melbourne. For tips on cooking your Crays, please see article-cooking-crayfish.

Gunditjmara country

Traditional Owners — This dive site is in the traditional Country of the Gunditjmara people of far south-western Victoria which continues over the state border into a small part of south-east South Australia and is bordered by the Glenelg River to the west and the Wannon River in the north. This truly ancient Country extends 100 metres out to sea from low tide and also includes Deen Maar (aka Lady Julia Percy Island) where the Gunditjmara believe the spirits of their dead travel to wait to be reborn. We wish to acknowledge the Gunditjmara as Traditional Owners. We pay respect to their Ancestors and their Elders, past, present and emerging.

Portland Bay Reef Location Map

Latitude: 38° 20.706′ S (38.3451° S / 38° 20′ 42.36″ S)
Longitude: 141° 37.645′ E (141.627417° E / 141° 37′ 38.7″ E)
Datum: WGS84 | Google Map
Added: 2022-05-17 08:04:27 GMT, Last updated: 2022-05-24 12:48:39 GMT
Source: Navionics Chart
Nearest Neighbour: Whalers Reef, 1,518 m, bearing 309°, NW
Portland, Discovery Coast.
Depth: 10 to 15 m.

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DISCLAIMER: No claim is made by The Scuba Doctor as to the accuracy of the dive site coordinates listed here. Should anyone decide to use these GPS marks to locate and dive on a site, they do so entirely at their own risk. Always verify against other sources.

The marks come from numerous sources including commercial operators, independent dive clubs, reference works, and active divers. Some are known to be accurate, while others may not be. Some GPS marks may even have come from maps using the AGD66 datum, and thus may need be converted to the WGS84 datum. To distinguish between the possible accuracy of the dive site marks, we've tried to give each mark a source of GPS, Google Earth, or unknown.