Boat anchor

[rcain1]

I actually pulled an anchor up with my anchor last season. It had a 50ft line tied to it and it was in 70ft of water.
When i started to pull it in I was afraid it was a body, I kid you not!

AWAP do you dive Belton often? The only local diving I have done is at Stillhouse. I want to find some dive sites at Belton.


Oh, if you need more anchors, Belton seems to have a fairly good supply. Plus it is good practice using a lift bag.[/QUOTE]

 

[tiswango]

I had a big debate once if Dead boat diving was more, equally, or less dangerous than cave diving? I've done both, so I have no room to preach, but the boat is your number one safety device and the ability to bring it to you when the fit his the shan is a BIG plus. Don't you have any friends that want to spend some time on the water while you dive. Then if the anchor doesn't hold, the boat can still come to you. (Assumption is made that the person in the boat can operate it safely in case of emergency)

 

[rcain1]

There is a mathematical equation every boat owner knows
Boat = friends
We sometimes have friends come with us that don’t dive but most of the time everybody is a diver.
I may try diving down 20 to 40 ft and looping a rope around a stump or log and tying both ends off on the boat. When I get ready to go all I have to do is untie one end.

 

[tiswango]

Boat = friends

2 divers diving + 2 divers on the boat = a great day on the water with everbody diving. Referred to as the "2 up 2 down".

Only three friends....

AB go dive while C is on the boat. AC go dive while B is on the boat. BC go dive while A is on the boat.

Safety is a matter of good planning. The problem here isn't really the anchor, its making sure the boat is there at the end of the dive. There are better ways to solve that problem besides buying a new anchor or tieing into a log.

As I said, I have dead boat dove in the ocean once and we used the rule of 1/3s in gas planning so that we made darn sure we got back to the boat. I couldn't really relax so the dive wasn't nearly as much fun.

We also gave up on grapneling wrecks and switched to a "bruce" anchor on an orange ball for wreck diving. The bruce hits the sand, digs in, and we pull down to the wreck. Its a great set up.

But Pipedope already laid out the anchor wisdom, the next step is finding out what the bottom make up is to pick the right tool for the job.

 

[miketsp]

After having to chase my boat down on Belton once, I decided to go with a two anchor system.

It's obvious for those who know but for those that don't:
Both anchor ropes should attach at the same end of the boat.
Don't even think about leaving a boat unattended with 1 at the prow and 1 at the stern.

 

[DA Aquamaster]

As indicated above a heavy chain in front of the anchor helps to keep it in place. As a minimum, the chain should be at least as long as the boat and 2 times the boat lenght is preferred. The weight of the chain acts as a shock absorber and helps the anchor stay put better in rough seas.

An anchor line 5 times the depth is ideal but can be problematic in a relatively small but deep alpine lake or along a dam in a reservoir. For example in 150 ft of water you would want 750 ft of anchor line, but then you also end up having to be at least 730 ft (plus your boat lenght) off shore to prevent the boat from potentially going aground if the wind shifts even with an extremely steep bank. This can sometimes put you a long way from where you want to dive. This is where a longer and heavier chain can help compensate for a shorter than desired anchor line.

Leaving someone on board is a far better solution though and is a good idea in any situation where you are not tied to a well set mooring bouy.

If you use two anchors put them both off the bow. Actually, I would never put an anchor off the stern under any circumstances as if the seas pick up and the anchor holds, you will end up shipping a lot of water over the transom and you may in fact be the first to discover a new wrecksite at the end of your dive.

 

[saintsfan]

for the line,in a lot of cases thats not that easy to do especially on a small boat.I just read that yesterday on their website.I had always tried to follow the 5-1


{QUOTE=DA Aquamaster]As indicated above a heavy chain in front of the anchor helps to keep it in place. As a minimum, the chain should be at least as long as the boat and 2 times the boat lenght is preferred. The weight of the chain acts as a shock absorber and helps the anchor stay put better in rough seas.

An anchor line 5 times the depth is ideal but can be problematic in a relatively small but deep alpine lake or along a dam in a reservoir. For example in 150 ft of water you would want 750 ft of anchor line, but then you also end up having to be at least 730 ft (plus your boat lenght) off shore to prevent the boat from potentially going aground if the wind shifts even with an extremely steep bank. This can sometimes put you a long way from where you want to dive. This is where a longer and heavier chain can help compensate for a shorter than desired anchor line.

Leaving someone on board is a far better solution though and is a good idea in any situation where you are not tied to a well set mooring bouy.

If you use two anchors put them both off the bow. Actually, I would never put an anchor off the stern under any circumstances as if the seas pick up and the anchor holds, you will end up shipping a lot of water over the transom and you may in fact be the first to discover a new wrecksite at the end of your dive.[/QUOTE]

 

[Tiny Bubbles]

I dive off a small boat (the "tiny bubbles") and I second everything everyone says about a 5 or 7 to 1 scope on the anchor rode (that's the rope for you land lubbers), about not attaching an anchor to the stern (want waves breaking over your stern if your bow anchor drags?) and especially about a generous amount of heavy chain. The chain does act as a 'shock absorber' like DA said to some extent, but it's even better than that. It makes the anchor rode sag. It sags like your clothesline sags when you hang your heavy BC on it to dry. Imagine your boat is at one end of the clothesline, and your anchor is at the other. Hang a bunch of heavy chain in the middle. Your boat is now pulling the anchor DOWN into the ground and not UP towards the surface. I know...the chain will lay on the bottom and drag the anchor across the bottom and not down, but the flukes are angled down and the anchor will dig in, rather than being lifted up like it would be without any chain. Your plastic pail doesn't have flukes and it won't dig in, so I don't believe a heavy pail is the right answer. My advice about anchors: get one size bigger than 'recommended' for your boat, since it's GOTTA hold while you're diving. And get a minimum of 1 boat length (that's almost 4 times the length of chain you have!) of the biggest heaviest chain that you can connect to said anchor without getting too ridiculous about it. Even more chain would be even more better. Every foot of heavy chain makes a difference in how well the anchor will hold.

-Tiny-B.

 

[pipedope]

Just to make things more interesting there are more exceptions and tricks. Like I said, there are several books on the subject.

If the bottom is bedrock and is fairly slick such that nothing will hook into it then you either need to bolt a mooring into th rock or liveboat it. To put in a mooring requires all sorts of permissions and stuff to get permission.

The scope you need is variable depending on the type of anchor, the type of rode and the depth of water. A bruce anchor with combined chain/rope rode in >100' of water will happily hold on 3:1. A standard Danforth with a short chain and mostly nylon rode in 10' of water is going to want 7:1 or more to set although it may continue to hold on shorter scope once set.

If you set multiple anchors you have to decide if you want the boat to be able to swing or not. In a protected cove it might be better to anchor bow and stern and not let the boat swing. If the anchorage is exposed (most dive sites) then you want the boat to swing to face wind and waves but remember that you don't want the anchor rodes all tangled so the use of a good swivel is a good idea. There are a number of ways to rig a temporary mooring with normal anchors and a float ball. This is nice if you want to be in one location fro several days but want to be able to take the boat out to play without lifting and resting all of your ground tackle every time.

Good God, am I babbeling again?????

Maybe I will start writing this stuff up and putting it on a web site. WAY to much to type in this little window.

 

[tedwhiteva]

Back to a basic point - not an especially good idea not to have someone on the boat.

Why do you think OSHA requires a surface support team for all but recrational diving.