Welcome to Total Bottom Time!

Total Bottom Time is my online personal dive log. A place where I can share my dives with friends, family, other divers, and the world. You can find out a bit more about me and see my full log of dives by clicking on my profile on the right. Feel free to subscribe to my dives via email or RSS.

Below are just some of my latest dives.

After a long time off, I got my first dive of the season under belt. The weather has been even windier than normal in Wellington but the Taputeranga Marine Reserve was relatively calm. The visibility was bit cloudy in places but overall it was a great afternoon for a dive.

Shortly after descending we headed west and ran into this school of fish. Not exactly uncommon but this was one of the more sizeable schools I've seen at Mermaid's Kitchen.

School of fish

Further along, I stumbled across the shell of the head of a crayfish. It was still very colourful and intact. Hard to know how it died. I had hopes that maybe an octopus had preyed upon it but a search of the area didn't turn up any signs of an octopus (not that they're easy to find).

Shell head of a crayfish

After about 25 minutes of heading out, we started to make our way back in. Came across a white sea cucumber and a blue moki that are common in the area.

White sea cucmber

Blue moki

Towards the end of the dive the swell started to pick up. The ocean was ...

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The third and final training dive of the Self-Reliant Diver Course was essentially a dive planned and led by me. I choose the dive profile and the route taken then led the dive as if I were solo. I chose a max depth of 10 metres and a max time of 35 minutes with a turn around time limit of 17.5 minutes or 133 bar, whichever came first. That profile didn't require as much air as the second dive of the course so I only had to bring the little 2.7 litre pony bottle with me.

But the third dive still had a number of objectives:

1. Write the depth and time on a slate at 20 bar intervals
2. Turn around at a predetermined time limit or air pressure limit
3. Navigate the entire dive without assistance
4. Switch to the redundant air supply
5. Deploy a surface marker buoy (SMB) on reel with a line while breathing off of the redundant air supply
6. Do all of the above within the planned dive profile 

I used the same slate as the second dive to write the depth and time since the slate has multiple "pages".

Navigation was a combination of compass ...

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The second training dive of the Self-Reliant Diver Course involved some planning. The main item to plan was how much air would be necessary for the dive using the surface air consumption (SAC) rate determined on the first dive of the course, which was 20 litres/minute.

Here are the formulas:

Air required = SAC * ((depth + 10 metres) / 10) * time * 1.5 reserve

Cylinder size in litres = air required / maximum pressure

For the second dive we planned for a max depth of 12 metres for 50 minutes and here's how the formulas worked out.

Air required = 20 * ((12 + 10) / 10) * 50 * 1.5 = 3300 litres

Cylinder size = 3300 / 200 = 16.5 litre cylinder

I was using an 11 litre cylinder main tank, which meant I need an extra 5.5 litre cylinder. However, the pony bottle I used on the first dive was only a 2.7 litre cylinder. That meant I need a larger cylinder as my redundant air supply and the only larger cylinders available were the 11 litre cylinders.

So I went on the dive with one 11 litre cylinder on my back and one 11 litre cylinder in front of me clipped to the left-hand side ...

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