Diving off small boats -- Questions

[Nemrod]

Rather than using a fender as a float I have a large inflatable 30" diameter orange commercial fishing buoy. It is a lot more visible than a fender and commercial boats are used to seeing them and won't confuse it with a lost fender. Plus it has a lot more buoyancy and would be harder to get pulled under by divers.

I also have a large inflatable bright yellow bouy. I often anchor and then set the anchor rode to the bouy and then tie the boat to my bouy. This way I can move off the anchor site if need be--and there are various reasons you might wish to do that.

I prefer to go up and down the anchor line whenever possible.

If you boat was dragging off your anchor is not right or you are just not setting anchor correctly. Once the anchor is on bottom you should back down on it to set it. I assume you have at least 15 feet of chain (or more) since I recall your boat is about 21 feet?

Diving from a small boat takes some practice to figure it all out. The boat, at anchor should be flying a dive flag and in your state I recall that the alpha flag is required as well and the tug skipper would be knowledgeable of it's meaning.

Do not anchor in a shipping lane.

When I anchor I always hit the "Fix" button on my GPS units and as well set the achor drift warning. This way I know I am drifiting and I also know where I left my divers (assuming I am skipper and not diving).

N

 

[Nemrod]

One other thing, rather than asking Gulf Coast folks or Wales folks or Easties how they do it, observe how the locals do it and then copy them. Each area has unique and time developed ways of doing things--because it works there--it may not work elsewhere.

In the Gulf we use grapple type anchors on wrecks often. I usually prefer to set my achor (a Fortress) beside the wreck in the sand or if it is live bottom then I definitly go for the sand. My side scan sonar is very helpful in determing the lay of things.

Oh, the captain is always in charge. I don't know which of you is the captain of your boat, but whoever it is, that is the person in charge.

N

 

[LeadTurn_SD]

I don't understand this -- I'm interested in the idea that it's preferable to have the boat upwind and drifting down on the divers. This is what our pilot was specifically trying to avoid. In current, it always seems that the boat tries to be downcurrent from the divers, and let them drift down on it; is it different in wind?

First, congratulations on your new boat! It sounds like you and Peter are examining all the issues related to safe boating carefully, asking the right questions, and learning the necessary skills very quickly. Well done!

I think you’ve gotten some good advice so far. I’ll just amplify a few points that were already made, from my perspective as an ex-Merchant Marine deck officer and current small boat owner / diver. Once upon a time I sailed aboard tankers, container ships and tugboats pulling large barges in your neck of the woods

1. Wind: Wind and chop will have a small effect upon a surfaced diver, but a large effect on the boat due to the “sail area” the boat presents. It is often best to position the boat UPWIND of the diver, and let it drift down towards the diver. This approach is preferred because it prevents a heavily loaded diver from having to “chase” the boat as it is blown downwind, and the boat can provide a lee for the diver(s). If you are worried about the boat “hitting” the divers as it drifts downwind, the boat captain/driver can position the boat so that it will “miss” the divers by a few yards and then simply tosses/hands a drift line to the diver(s) as the boat drifts by them (and “hitting” the divers is not really much of a safety concern in a “smallish” boat that is slowly drifting downwind since the divers will simply “fend off” as the boat gets to them).

2. Anchoring in or near shipping lanes in confined waterways: Ignoring any right-of-way and prohibited anchorage issues, if you are near the edge of an area that large vessels regularly pass though, I’d probably avoid anchoring the boat. My guess is that in the case you described, the tugboat was well aware of the position of the sunken barge and would stay on the deep-water side of it, so there was no real danger, but for safety reasons you should be able to quickly move your boat clear if needed. As already mentioned, a large ship or tug and barge will not be able to maneuver much. You’ll need to get out of their way.

3. Reliability & Redundancy on a small boat: I apologize if you’ve already have thought through all of these things, but here are some things I’ve learned on vessels large and small

• Electrical problems and fuel contamination are two biggies to watch for with small boats, but are easily avoided with diligent maintenance. A spare, good quality hand-held VHF radio is a good idea, just in case of a major short or battery failure that takes out both your engine and primary radio.

• Mechanical problems with modern outboards that are properly maintained are rare, but can occur. Just like with diving, think through the “what-if” scenarios, and try for redundancy in critical systems when possible. Two “what-ifs” are engine or steering failure. A backup outboard, called a “kicker” in some areas, is often a good idea on small boats operating in the ocean or other elevated-risk waterways to help reduce these risks. I prefer a manual-start over an electric-start kicker, so that it is completely independent of your battery/electrical system. The kicker needs to be big enough to actually push your fully-loaded boat, which probably rules out the small 9-12 hp engines in most cases. On my 21 foot boat I’ve found a 20 hp kicker to be about right, but it does take a strong pull on the rope to start it.


Have fun with your boat!

 

[SkipperJohn]

Excellent point on that chain. I one time lowered a 24 pound anchor in around 400 feet of water and with around 1,000 feet of line out it never hit bottom! (wild currents in an area known as the mud hole around 30 miles south of the mouth of the Hudson River).
I have since made a few changes to my rode when anchoring in that area.
Chain: 30 feet
Line: 1/4 inch
Anchor: 27 pound.
I know this is extreme but I never had a problem again.
In other areas I anchor with only 6 feet of chain and generally use my 24 pound anchor, but I stuck with the 1/4" line. The lower diameter allows it to sink faster and not be as influenced with the current. While anchoring along the continental shelf in over 600 foot of water the thinner line helps me store more of it in my locker. But here I bump up to 50 foot of chain.
While you will never need a setup like I described here, try lighter line and more chain.
Also, I NEVER use my danforths around wrecks. If it slides into a wreck you can kiss it good bye (although as a diver you have more options than a fisherman does... but do you really want to dive to recover your own anchor?). Here in the North East US we use wreck anchors-grappling hooks made to snare the wreck. Then when leaving you simple take in the scope then use the engines to gently straighten out the arms of the hook. Re-bend them back into place after retrieval.

 

[Peter Guy]

Just for the record -- I, Peter, was not on the boat and the skipper was an experienced (and CG Licensed) small boat handler.

Things will get better with time and experience.

 

[Charlie99]

. He was trying to position the boat so we could swim downwind to it, and it wouldn't be upwind and drift down onto us.

It's one of those things that is obvious after you hear it, but it's worth noting that if both you and the boat are adrift,then then effect of the current disappears. Any relative motion is caused the by significant wind-generated drift of the boat vs. the near zero effect of the wind on divers.

Currents and wind directions are often different. Swimming downwind to catch a boat is often a losing proposition since wind can move a boat surprisingly fast.

OTOH, even a very fast current has no effect other than making the timing of your release from the buoy a bit more critical.

Who's in charge, once the divers are on the surface?

Of course every person is always in charge of their personal safety, but in terms of a smooth reboarding it generally works best for the Captain to be calling the shots.

He knows what type of approach he plans on making. He probably has the better idea of what sort of wind drift his boat will have. He's the guy that has the best idea of the optimal time for divers to do things like letting go of the shotline/mooring buoy or for drifting divers to begin their swim of the last few feet to the boat.

 

[String]

Current can have more of an effect than wind on a boat, depends on boat and the strength of current.

Small RIB with a large(ish) draught will be far more current influenced than a big sided hard boat for example.

Wind and current in different directions are the most fiddly for a boat as it keeps trying to rotate.

 

[TSandM]

We really didn't have any current at this site; the whole challenge was the wind. We quickly learned that it affects the boat more than the divers! The good friend who was running the boat for me was facing a bit of a hurdle, too, because he's used to picking up divers off his own boat, which is a RIB and has very little windage.

I think one of the big things I've learned from this thread is that it's okay to position the boat upwind and let it drift down on the divers. That just seems like a very effective way of using the conditions instead of battling them, as long as it doesn't turn out to be a diver bashing with a boat

 

[dumpsterDiver]

....I think one of the big things I've learned from this thread is that it's okay to position the boat upwind and let it drift down on the divers. That just seems like a very effective way of using the conditions instead of battling them, as long as it doesn't turn out to be a diver bashing with a boat

Great! It only took 6-8 people telling you the same thing to get you to believe it!

 

[String]

I think one of the big things I've learned from this thread is that it's okay to position the boat upwind and let it drift down on the divers. That just seems like a very effective way of using the conditions instead of battling them, as long as it doesn't turn out to be a diver bashing with a boat

In those conditions id be tempted to approach dead into the wind. That way you can use the wind as a brake. Motor towards the divers in tickover and going to neutral for the last few meters and use the wind to stop you next to the divers.
Approaching the other way you run the risk of overshooting or hitting them.

Small RIBs generally its always better to do any slow speed stuff into the wind (or current, whatever has most effect) for that reason.