anchoring an empty dive boat

[jchaplain]

Well, sometimes people who don't own a boat (or in our case lived aboard one) don't understand that you cannot be onboard 100% of the time. However, the suggestions about contingency plans in case the boat DOES get away from you (or you come back up short of the boat) are good ideas. That's why I love this Board!

Smooth seas & fair winds,

I know, I like this board a lot too....I didn't mean to sound short when people were going off topic to the discussion, sorry if I did, I was just trying to pull it back to the subject. :57:

A lot of considerations about diving an empty boat are just common sense....don't do it in rough seas....don't do it in boating channels...etc....
But on a nice day on a flat sea it can be a pretty safe practice given that proper precautions are taken. Much similar to the discussion on safe solo diving.

John C.

 

[tedwhiteva]

I know, I like this board a lot too....I didn't mean to sound short when people were going off topic to the discussion, sorry if I did, I was just trying to pull it back to the subject. :57:

A lot of considerations about diving an empty boat are just common sense....don't do it in rough seas....don't do it in boating channels...etc....
But on a nice day on a flat sea it can be a pretty safe practice given that proper precautions are taken. Much similar to the discussion on safe solo diving.

John C.

John, the final choice is yours, but..
Been there, done that, and got the T-shirt - from the Coast Guard side of the problem.

SCUBA from an empty boat is a lot different than swimming from an empty boat. If nothing else, PLEASE have in your dive plan what you would do IF you came up and the boat wasn't there. No different than the other emergency planning done before a dive.

Safe diving

 

[matt_unique]

I've been tossing around ideas for anchoring my boat when I leave it at the surface empty. ( 24 foot cabin cruiser, 2 divers.) Of course, the last thing you want is to return to the surface to find the boat drifted away.

My first idea to prevent this was to go to an oversize anchor. This would of course help, but it's still not a positively sure thing.

My new idea is to dive to the anchor to check that it is secure as I always do, but now I have made up a large loop of chain and rope that I intend to have attached to the anchor and throw over some large nearby rock to ensure that even if the anchor does let go the boat will not drift away.
Because of the dive conditions in Boston ( very low vis) I now always dive with a reel to the anchor anyway and return there at the end of the dive, so it would be easy to undo the safety loop before returning to the surface.

My question is....has anyone else ever considered this or used similar techniques for safe anchoring while diving?

John C.

You may recall from previous conversations I used to do the same - anchor or moor the boat then dive with an empty boat (night and day). I had one instance at Halfway Rock that changed my mind about it. We dove for 45 min, surfaced, got aboard the boat, then a few minutes later while tearing down equipment we realized we had drifted about 50 yards. My boat drifted fast and far - could not believe the distance we had moved in a short period of time with an increase in the wind. If we were down longer we would have surfaced at HWR with one hell of a problem. Now I solo dive with dive buddy or whoever standing watch topside with laminated directions, procedures, and GPS coordinates. Not a lecture of course just my .02 on how my thinking changed about it. I used to do the U853 with no one on the boat....talk about a surface swim even IF we had no current...ha ha ha....7 miles to Block Island.....that's a party.

With that being said, if you're going to do it I think you got your bases covered. Good anchor, descend down the line to verify the set (set it better if necessary), run a reel from the anchor so you can return to your line, etc. I would use more scope for this purpose though. If the anchor did break free you would want sufficient line so that the anchor would drag on the bottom at the very least. Many of our sites around here (Halfway Rock as a perfect example) get deeper quick.

An extra support at depth as you described (chain around rock) just increases safety. There are many sites where this would not be an option unless you tied onto a wreck (if wreck diving).

--Matt

 

[jchaplain]

An extra support at depth as you described (chain around rock) just increases safety. There are many sites where this would not be an option unless you tied onto a wreck (if wreck diving).

--Matt

Yep, I agree, it IS a risk leaving a dive boat empty on the surface.

Yet, everything about scuba diving is risky, eh? Pretty much everything about life is risky. What we humans who manage to survive do ( in life, in scuba, and in boating) is take circumstances under consideration and then minimize the risk by preventative methods ( look both ways before crossing.....for scuba we use redundant equipment, etc....) until the safety level seems acceptable. Empty boat diving is the same.

John C.

 

[H2Andy]

Yet, everything about scuba diving is risky, eh?

somethings are riskier than others. for example, diving 40% Nitrox to 130 feet
is far, far, far riskier than diving air to the same depth.

likewise, diving overhead without training is not just risky, it's russian roulette.


i fear the level of "risk" entailed in leaving your boat unnatended exceeds
my definition of "acceptable risk"

(and we all know that safety is just an acceptable level of risk)

 

[jchaplain]

somethings are riskier than others. for example, diving 40% Nitrox to 130 feet
is far, far, far riskier than diving air to the same depth.

likewise, diving overhead without training is not just risky, it's russian roulette.


i fear the level of "risk" entailed in leaving your boat unnatended exceeds
my definition of "acceptable risk"

(and we all know that safety is just an acceptable level of risk)

On a calm day in good conditions in Boston Harbor it really is not very risky.
People do it ALL the time.

John

 

[H2Andy]

well, you have a point there

i was thinking "my" local conditions, off shore Jax

i'd never do it here

 

[matt_unique]

Yep, I agree, it IS a risk leaving a dive boat empty on the surface.

Yet, everything about scuba diving is risky, eh? Pretty much everything about life is risky. What we humans who manage to survive do ( in life, in scuba, and in boating) is take circumstances under consideration and then minimize the risk by preventative methods ( look both ways before crossing.....for scuba we use redundant equipment, etc....) until the safety level seems acceptable. Empty boat diving is the same.

John C.

I think you have your bases covered as I mentioned in the last note. 20 anchors and 100' of heavy chain would hold your boat in place (ha ha) but obviously not a good balance of benefit to effort. I think a line to the anchor is key - if your anchor does let go you will most likely be able to fin faster than she will drift in the wind.

We'll have to meet up sometime and raft while we dive.

--Matt

 

[Charlie99]

I think a line to the anchor is key - if your anchor does let go you will most likely be able to fin faster than she will drift in the wind.

Fin???!!! With a reel and line to the anchor rode, you just reel yourself in like a big fish

Have you ever actually tried to catch a boat drifting in the wind ?? --- lots of boat scoot along pretty fast, even in light winds, unless it has a deep V hull or a keel.

 

[Chuck Tribolet]

The real world of a small dive boat is that you are going to leave
it unattended.

Check the anchor at the beginning of the dive.
Make sure you have enough scope so that if it does drag, it the
anchor will still be on the bottom.
Make sure you have enough scope that it won't drag.
Use an appropriate anchor for your bottom type.
Check the rode periodically for wear and tight shackles.
Safety tie the shackles.
Attach the line to the boat twice, once at the bitter end, and
once at the appropriate lengh.
If you are going to upsize anything, go for a longer chain, not
a bigger anchor.