Techniques for boat diving without surface support

[scubaozy]

I did dive quite a bit in Mediterranean without a support, it is pretty common from a RIB actually. Diving is done shore near, in bays, you drop an anchor to rocky bottom. When descending ensure that anchor is nicely placed holding well. At the end of the dive, free the anchor from the crack you placed it in. End the dive, pull the anchor back. Mitigation is to swim back to shore.

 

[Tom_Ivan]

Agreed - but I’d actually call it extremely stupid!

I'm trying to figure out whether this thread is an example of normalization of deviance or some lesser known behavioral safety lapse.

I think we should start with a blanket statement, "This is neither recommended nor safe. However if you choose to do it anyway, here's how to decrease the risks. Somewhat."

In a way, all diving is normalization of deviance isn't it? You would be safer if you stayed home. We all have to decide for ourselves how how much risk is acceptible. For example, some divers are happy diving solo and others are not. Some divers will dive off a unattended boat and other will not.

The OP did not ask if we thought diving from an unattended boat was the right decision. He asked for advice on how to make himself safer, given that he was going to dive that way anyway.

 

[2airishuman]

When I dive from an unattended boat, I do so within swimming distance of shoreline that permits a safe exit.

In many cases this involves situations where the shoreline is privately owned, not readily accessible by car, or where there are laws/ordinances restricting shore diving. So I dive from my boat.

In some cases where the shoreline is public land but inaccessible by car I have found it easier to beach my boat and scuba dive from shore.

 

[Russjstewart]

As a former zodiac owner (Futura MK 11) my main concern is how is the bow cleat attached to the boat. Is it glued on, is it held into the fibreglass with self tapping screws or is is bolted on through the fibreglass with large washers underneath the glass.
Anything that is glued on will eventually fail and Murphy says it will fail at the worst time, self tappers are a bit better.
With my soft bottom Zodiac I put a stainless steel ring in the middle of a length of dyneema, then ran the dyneems through the grab handle on the bow and back to eyebolts mounted either side of the transom. This way all the load was on the transom, not on glued on attachments.

 

[Still Kicking]

As a former zodiac owner (Futura MK 11) my main concern is how is the bow cleat attached to the boat. Is it glued on, is it held into the fibreglass with self tapping screws or is is bolted on through the fibreglass with large washers underneath the glass.
Anything that is glued on will eventually fail and Murphy says it will fail at the worst time, self tappers are a bit better.
With my soft bottom Zodiac I put a stainless steel ring in the middle of a length of dyneema, then ran the dyneems through the grab handle on the bow and back to eyebolts mounted either side of the transom. This way all the load was on the transom, not on glued on attachments.

If a cleat on a fiberglass boat is not held in place with heavy (like 3/8") stainless through bolts and backed with fender washers AT LEAST, I would run away from that boat as fast as possible. You can bet the manufacturer cut lots of corners elsewhere.

On my inflatable, I always secured the anchor line with a stainless caribiner to the 3/8" lifeline that ran all the way the boat with a grommet about every 12." If that lifeline gave way, something very, very bad had happened and I had bigger problems to worry about.

 

[lowwall]

If that lifeline gave way, something very, very bad had happened and I had bigger problems to worry about.

 

[KeelsonGraham]

I see no real problem with leaving the dive boat unattended as long as certain conditions are met. Those who say it should never be done are probably right....for their areas and level of experience. In other areas, it's perfectly fine. In some areas, it's easy to see the boat from the bottom. Honestly, nowadays I would worry to much about theft and vandalism to leave the boat alone but each to his own.

Yes, it’s more about the boat and your level of seamanship. Sailboat owners (such as me) regularly leave their boats at anchor, unattended. Some do it for days on end. With the right anchor set-up it’s perfectly normal behaviour - not at all deviant.

On the other hand, a small inflatable would be best tied to a mooring ball.

I’m moving to the Caribbean soon, and can’t wait to dive at the locations of my choice, in weather and sea conditions that I’ve assessed with all the nav kit on board, at my own pace, and only when I feel in the mood. Not having to follow some sketchy dive guide, being able to potter about on the surface and descend when I’m ready, not when I’m told to, are further benefits.

If I think the on-board oxygen facility, is a backup worth having, then I’ll buy a set. It costs buttons compared with boat ownership.

The OP’s precautions are sensible. To that I would add a hand-held VHF radio, and a bungee cord to attach your BCD to the boat if you’re tired after surfacing. Finally, if you’re worried about retrieving your anchor, use a tripping line with buoy.