anchoring an empty dive boat

[Nemrod]

I would not anchor my boat and leave it without someone to sit watch unless your within swimming distance of the shore. It is just common sense. In calm conditions, well traveled area, near shore, sure.
I also am not sure throwing chains over reefs or rocks is very ecologically sound.

I don't think salvaging an anchored boat with a dive flag up is legal, if a person salvaged my boat when I found them they might need medical attention afterwards. Just me maybe. N

 

[jchaplain]

Thank You Submariner!

I was wondering if others do this and looking for additional input on the technique. Your response is the only worthwhile response so far.
A Bahama sling! I'm just glad to know it is a used practice.


Geez...What is it about this hobby of diving? It's impossible to get a straight answer around here without people responding things like...

"Did you call your mama on shore first?"
"Never do that..you might die if you leave your boat empty....lol....."

John C.

We used to use this technique a lot on our sailboat in the Bahamas, where it was called, fittingly enough "a Bahamian Mooring".

It works very well.

 

[jchaplain]

Though from what I understand laws have changed over the years, I would be worried that someone finding a boat with nobody on board might consider it abandonded and/or salvage and tow it away, regardless of the fact that it is anchored. It's bad enough when someone tries to steal your dive flag while you're tied to it...

Nobody is going to salvage or loot a boat that is sitting for a half hour anchored with a dive flag on it...at least not in Boston Harbor.....thats the least of my worries.

John C.

 

[jchaplain]

1) the right anchor for the holding conditions. One of the best all-round anchors is a Bruce.
2) the right size anchor for your boat. The usual rule of thumb is 10 pounds per foot, then adding some for good measure. So with a 24' boat you probably should think about a 25-30# anchor.
3) lots of rode with several feet of chain.
4) setting the anchor properly. Once you put it down, drop back to set it.
5) deploying the right amount of scope. THIS, along with the weight of the chain is what actually keeps your anchor at the right angle to stay put. In good conditions, 7:1

Here's a good article about anchoring: http://www.texasgulfcoastfishing.com/anchors.htm

Bonne chance,

I know that....but even using the right anchor, rode, length of line...etc....an anchor can still drag if it is not caught on good bottom.
I was asking about using an additional sling.
But thanks for the post.
John C.

 

[Charlie99]

You don't think a loop of chain/rope attached to the anchor and tossed over a 2000 lb rock might prevent the boat from drifting?

Am I missing something? I'm not tryng to be a wiseguy...really!

Since you have a reel and line to the anchor, a drifting anchor just means your boat becomes a really, really big float ball

The problem is separation of you and your boat, not a dragging anchor.

It's impossible to get a straight answer around here without people responding things like...

"Did you call your mama on shore first?"

You fix potential problems two ways:

1. Make it very unlikely to occur, and/or
2. Minimize the consequences so that it's not as big a deal if the problem does occur.

When dead boat diving, even if the boat is well anchored, you still have the potential problem of not finding the anchor line for some reason, coming up downcurrent, and not being able to swim back to the boat.

One way to minimize the consequences of this is to have a way to activate a search and rescue in a timely fashion, in the right spot. It's a bit more than "Did you call your mama on shore first?", but I didn't spell out the details because I figured they were obvious. Perhaps it isn't.

 

[jchaplain]

One way to minimize the consequences of this is to have a way to activate a search and rescue in a timely fashion, in the right spot.

Thanks,
I really do appreciate the response, but the question was....

"Has anyone tried an anchor sling?"

And the statment of concern really was the possiblility of a dragging anchor and how to prevent that. The best anchors have been know to drag depending on the bottom.

I like to stay on topic and I was trying to find out if anyone else uses such an anchor sling or has any additional comments/hints on making or using one.

John C.

 

[saintsfan]

A large rock will definately hold the boat.My concern is either rope or chain slipping(depending on the shape of rock) and if using rope ,cutting.I have a firm belief in chain and rode the coastguard reccomends a 7-1 ratio .I always decend the anchor and considering I have 50' of heavy chain I rarely see the pressure even make it to the anchor.usually only 10-20' of chain is off the bottom and the rest is just laying there.Ohyeah I have a 26' cabincruiser.I would prefer to just toss out a second anchor as mentioned previously. I think the sling would work as a second option as well. as far as topics go this one is doing pretty well staying on course

 

[DA Aquamaster]

A 2 to 1 ratio of heavy chain to boat lenght is a good idea. It acts as a shock absorber for the whole system, it keeps the rope off the bottom and away from potential abrasion and it helps maintain the flukes on the anchor at the proper angle.

With regard to a safety loop around an object on the bottom, wreck divers tie the anchor into the wreck all the time and then "anchor" on what amounts to a very short nearly vertical rode that is then used as an ascent line. A critical difference though is that the dive boat is never unattended and the line is rigged so that the boat can cut away if neccesary and leave a float in place to provide an ascent line for the divers and faciliate resecuring the boat to the line later.

I would agree that the more safety and redundancy the better in the case of diving from an unattended boat. But you also have to realize that even with two anchors with at least one tied into the bottom that a failure could still occur and a plan to get yourself rescued is still a very good idea. In Boston harbor, a cell phone in a water and pressure proof container may be very handy to have along.

 

[SubMariner]

Thank You Submariner!

I was wondering if others do this and looking for additional input on the technique. Your response is the only worthwhile response so far.
A Bahama sling! I'm just glad to know it is a used practice.

Absolutely. It's even more fun when you have tidal currents that totally reverse. So you have to drop an anchor off the bow, set it, then walk the 2nd anchor to the stern & then set that one. Mucho fun.

Geez...What is it about this hobby of diving? It's impossible to get a straight answer around here without people responding things like...

"Did you call your mama on shore first?"
"Never do that..you might die if you leave your boat empty....lol....."

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!

I know that....but even using the right anchor, rode, length of line...etc....an anchor can still drag if it is not caught on good bottom.
I was asking about using an additional sling.
But thanks for the post.

My apologies. Your posts didn't indicate your level of experience.

Smooth seas & fair winds,

 

[jchaplain]

A large rock will definately hold the boat.My concern is either rope or chain slipping(depending on the shape of rock) and if using rope ,cutting.I have a firm belief in chain and rode the coastguard reccomends a 7-1 ratio .I always decend the anchor and considering I have 50' of heavy chain I rarely see the pressure even make it to the anchor.usually only 10-20' of chain is off the bottom and the rest is just laying there.Ohyeah I have a 26' cabincruiser.I would prefer to just toss out a second anchor as mentioned previously. I think the sling would work as a second option as well. as far as topics go this one is doing pretty well staying on course

50 feet of heavy chain????? WOW!!!
You MUST have a windlass, right? Either that or you have the arms of Popeye! :11:

I like it, and I also have an extra amount of heavy chain, but I couldn't imagine hoisting all that chain without a windlass ( and I don't have one.)

I agree, the concern is both object slipping, either the anchor or the sling......
The topology of Boston Harbor waters is such that there are usually a lot of rocks around of various sizes to sling to. The sling I made is about six feet in diameter and is about 1/3 chain ( for weight ) and 2/3 rope. I will be using as a redundancy anchoring method to increase the safety involved in leaving an empty dive boat on the surface.

John C.