Anchoring Technique ....!

[Valiente]

Originally Posted by ANCORALATINA

not that easy to participate to English speaking forums when English is not your mother tongue.. Is summer time here, and I send to you all a warm ray of sun !

Tudo bem...your English is fine, and besides, we are quite used to Portuguese syntax here.

As long as the discussion doesn't turn into an advertisement, I welcome the comments by anchor manufacturers to this thread and others like it. It is clear to me that anchor technology is still advancing, and that while there are many situations in which an older design will work for one boat in one place, the ideal is to find a design that will hold in the greatest number of situations. I highly doubt that, short of firing a grapnel from an explosive charge directly into the seabed, we will ever have a "one answer" anchoring solution, but if new designs can give most yachts equivalent holding power with less weight, or in a wider number of bottom types, I would never regret hearing an argument in their favour.

[xort]

ancora
are you saying the next gen anchors will never drag no matter what?

I did switch from CQR to manson supreme. I've yet to be "jolted" by a quick setting Manson. I have not dragged either; yet.

[ANCORALATINA]

Originally Posted by xort

ancora
are you saying the next gen anchors will never drag no matter what?

Absolutely not!.. Just saying that “next Gen” anchors are setting much faster and in a broader type of sea bottoms than the “old Gen” anchors… and nothing else!

[xort]

thanks for clarifying

[GaryHLucas]

Maine Sail,
Interesting post. I for one will admit to not being very good at anchoring. Back in the 80s it seemed like every time I anchored for the night, it dragged. So I could never get a sound sleep. My Etap 26 came with a 37 lb Danforth style anchor, that seems to hold very well, here in NJ. However the last time I anchored out for the night I got a rude surprise in the morning. We ate breakfast, and I started pulling up the anchor. Out of the water comes the rode at the 50 foot mark with 3 very tiny strands all that are left! We had anchored on the outside edge of a fleet of boats at around 11 PM. In the morning we were surrounded by additional power boats. One of them must have run across my rode in the dark!

Short of hanging mines on the rode to sink the bastards, what can you do about that?

[betodas]

Originally Posted by ANCORALATINA

Many Many thanks Scottyt, not that easy to participate to English speaking forums when English is not your mother tongue.. Is summer time here, and I send to you all a warm ray of sun !

Oi Ancora,

That was me who said that. May be I have to rethink it and get a Supreme instead.

[ANCORALATINA]

Betodas: Oi Ancora, That was me who said that. May be I have to rethink it and get a Supreme instead.

Oooopsss! I apologize Betodas, and thanks too for your king words!!

GarryHLucas: However the last time I anchored out for the night I got a rude surprise in the morning. Out of the water comes the rode at the 50 foot mark with 3 very tiny strands all that are left! we were surrounded by additional power boats. One of them must have run across my rode in the dark!
what can you do about that?

Perhaps this is where the “KELLET” may found a useful application, keeping the line down on the sea bottom.

[Maine Sail]

I finally got a question answered that has been nagging me for a while.

My three blade prop, in combination with my tranny and engine, at wide open throttle will develop a MAX of 880 lbs. of pull or thrust in reverse. This is a raw calculation and does not account for slip so in reality it is probably between 10-15% less efficient than 880 at WOT.

I like to know this because I set my anchor at 80% reverse throttle. The calculation at 80% accounting for slip is in the mid to low 500 pound range. Even at wide open throttle any anchor that can be dragged by 880 pounds of pull is not enough for a 30-38 footer..

My engine is 44hp and I swing a 16" three blade wheel. For the average 30-38 footer you would be at this level of reverse thrust or even less given HP & prop..

If you can drag your anchor in reverse at 80% throttle you should begin looking for a new anchor...!

[flyingwelshman]

I created an Excel spreadsheet to calculate how much rode to let out for different scopes for different depths, based on my boat.

Here is a screen shot of it:



You can see the formula that I used near the top in the formula window: =((A3 + 2)*3)+3-25

A3 = water depth; the first '2' = the depth of my transducer below the water surface (it's actually closer to 1 ft down, but this adds just a little safety margin); the '3' is the desired scope i.e. 3:1 - for 5:1 scope, this number would be 5 etc.; the '25' is the length of chain I have at the end of my rode.

The depth actually goes down to 90', but I only took a screen shot of the top portion of the page.

I printed this and there is a copy in my chain locker. That way when the anchor is set my crew only needs to know the depth and the desired scope and can let out the proper amount of rode without doing a lot of mental calisthenics.

I also played around and created a rode calculator that can be be used for any boat:



Just put in your boat's info, depth and desired scope and it tells you how much rode to let out.

I'm sure after a while, with more experience, this 'training wheel' won't be required, but I found it very useful.

Let me know what you think.

[betodas]

Originally Posted by flyingwelshman

I created an Excel spreadsheet to calculate how much rode to let out for different scopes for different depths, based on my boat.

Here is a screen shot of it:



You can see the formula that I used near the top in the formula window: =((A3 + 2)*3)+3-25

A3 = water depth; the first '2' = the depth of my transducer below the water surface (it's actually closer to 1 ft down, but this adds just a little safety margin); the '3' is the desired scope i.e. 3:1 - for 5:1 scope, this number would be 5 etc.; the '25' is the length of chain I have at the end of my rode.

The depth actually goes down to 90', but I only took a screen shot of the top portion of the page.

I printed this and there is a copy in my chain locker. That way when the anchor is set my crew only needs to know the depth and the desired scope and can let out the proper amount of rode without doing a lot of mental calisthenics.

I also played around and created a rode calculator that can be be used for any boat:



Just put in your boat's info, depth and desired scope and it tells you how much rode to let out.

I'm sure after a while, with more experience, this 'training wheel' won't be required, but I found it very useful.

Let me know what you think.

The formula should probably read a little differently. Correct me if I'm wrong but shouldn't the freeboard be added to the depth before subtracting the chain length? The formula you have has the free board being added to the chain length to be subtracted after you have multiplied the desired rode by the total depth.
Shouldn't it be =(B5*(B1+B3+E1))-E3
That way you have the desired rode (5:1) * your total depth (water depth + transducer + freeboard). Then subtract the chain.
So say you have a depth of 10 feet, transd is 2 feet and the free board is 3 feet. So you have a total depth of 15 feet. That would be 75 total feet of rode for a 5:1 ratio. subtract the 25 feet of chain and you should let out 50 feet of rode instead of the 38 listed.