Anchor line length?

[mookieo2]

How much anchor line do I need for 100ft of water. I have a little less then 150' and can't hook up.

 

[skargo]

Re: Anchor line length?

Appox.300' to 700' or more depending on conditions.

150' isn't going to cut it.

What body of water is this?

 

[ziggy]

Re: Anchor line length?

i believe the typical scope is 7:1
ya might be able to get to 3:1 or ya may need 10:1 in bad weather.

that's a lot of rode for sure.

i suppose it could be irrelevant at them depths, but don't forget to add the height of the boat above water into the equation. for my boat, that'd be adding another 3' or so to the hundred ya all already got.

agree w/skargo. 150' feet of rode aint gonna get it. that's almost perpendicular. not quite, but close enough i can see why ya can't hook up.

 

[choochooharley]

Re: Anchor line length?

you may be able to get by with 3:1 but the recomded minimum like others have said is 7:1 and that is in calm weather in rough weather you should have 10:1. So in 100 ft of water you should have 700 to 1000 foot of line. Good luck finding room for that. Also at the end of the rope you should have galvanized chain to attach the rope to the anchor that helps hold the anchor in. Just curious what type of achor is it.

 

[barbosam]

Re: Anchor line length?

Ya 7:1 scope is usually recomended, but carrying 700' of line can be a challenge. 300' in most situations will be enough for you and is still manageable. What size boat do you have? One thing you can do to help improve hook-up is to increase the length of chain. Some people will tell you to use chain equal to the length of the boat, but again this can be difficult to manage I try to use half the length of the boat. Honestly it comes down to what you can fit on the boat and be able to manage because in anchoring the more line you let out the better your anchor will hold. If you can't add a significant amount of line add chain.

good luck!

 

[themaniam1]

Re: Anchor line length?

If you trying to anchor just to fish I would add chain, about the length of your boat is a good rule if anchoring off shore or have the length of your boat if your are on inland waters (smaller waves in general). You need chain to protect the line but more importantly to get the anchor to bite into the bottom. The chain weights down the the anchor line and helps keep the anchor shaft laying on the bottom so when the boat pulls on the anchor line it pulls the anchor horizontally along the bottom. The chain also helps the anchor stay set by reducing the effect of the boat rising and falling with the waves and taking out the shock by creating "sag" in the line.

For 100 ft of water.
3:1 = 300 ft of line good for light breezes up to 10 knots. This does not include the extra length that it takes to make up for your boats freeboard (the distance from the water to the top of your gunwale where the line is tied off). That distance is calculated by freeboard X scope.

5:1 = 500 ft and good to about 25 knot winds.

7:1 = 700 ft and good for about 60 knt winds or overnight anchoring.

These are all rough measurements but work. Remember anchor line length is water depth X ratio (angle).

 

[Home Cookin']

Re: Anchor line length?

I've always wondered why the advice and formulas bother to mention freeboard--whether you add 3' to 100' or 700' makes no practical difference. For a 40' tall freighter, maybe. Or am I missing something?

 

[themaniam1]

Re: Anchor line length?

I've always wondered why the advice and formulas bother to mention freeboard--whether you add 3' to 100' or 700' makes no practical difference. For a 40' tall freighter, maybe. Or am I missing something?

It is not 3' but 21' you add on a 7:1 with a 3' freeboad. You add the freeboad X scope to keep the angle of the line what the scope is. So to have a scope of 7:1 in 10' of water you need 70' of line, that is if measured at the surface of the water. But if you have 3' of freeboad, now the line is raise and additional 3' and thus changing the angle to less then 7:1, (By the way, 7:1 is the scope with strongest practical holding power, 10:1 has the most holding power). To correct that you need to add 3' (freeboard) X 7(scope)= 21 extra feet of line to correct that.

Reality, the higher your freeboard the greater the angle change. 3' freeboard (most cruisers have this unless really big) will not make much of a change to the scope, especially if it is 7:1 which is a shallowest of the angles. But mathematically it does make difference so those of us who know it state it. I just add the 9' (3:1), 15' (5:1) or 21' (7:1) because I know but that is me (I have a 3' freeboard).

I think having enough chain is way more important in setting and maintaining an anchorage than adding the freeboard on with our small recreation boats.

 

[dan t.]

Re: Anchor line length?

We regularly anchor in 180 to 220 feet to fish halibut. I have a 10 lb danforth,24 ft of 3/8 chain and 300 ft of line, works good for fishing but I would never trust it for an overnight hook or in any kind of blow

 

[mookieo2]

Re: Anchor line length?

Thanks Guys. I should have specified earlier. I have a 20ft cuddy with a full canvas top that acts like a sail. I can't hook up the anchor at the reef in 80; of water. I fish in Long Island either in the sound or Atlantic ocean. I have 150ft but since I;ve been looking around on anchoring I realized there is no chain on my anchor. I will pick up 10-15' of chain. What size should I get? I'll grab 300' of line again what diameter?

 

[barbosam]

Re: Anchor line length?

I'd recommend 3/8" line with 3/16" chain and 1/4" shackles.

 

[Fed]

Re: Anchor line length?

And an anchor yanker.

 

[choochooharley]

Re: Anchor line length?

1/4" should be good for the chain propaly 15 ft or so.... as far as the rope probably 3/8" with the size of your boat....another thing to keep in mind depending on your knot tying skills....if you buy another 300 ft of rope dont leave that 150 ft you have at home you may need to combine them on a windy or rough day also you probably if you add it all together have 30 to 50 ft of dock line that could be tied together just things to keep in mind in a pinch....but always remember a chain (or rope) is only as strong as its weakest link.....

 

[barbosam]

Re: Anchor line length?

Another important piece of information we haven't discussed is what type and weight anchor are you using. The most common/versatile for your setup would be a fluke anchor at 6-9 lbs.

Side note: on the chain, 1/4" is not necessary strength wise, but a little more weight won't hurt to help weigh down the line. It's usually recommended to use shackles one size larger than the chain.

 

[choochooharley]

Re: Anchor line length?

Thats a good point about the anchor style I agree that the fluke or danforth style is best and you shouldnt be using a mushroom style or basically a weight on a string it would never hold no matter how much line you buy or how much or how heavy chain you attach

 

[dan t.]

Re: Anchor line length?

For a good hook up I recomend 3/8 chain,same length as the boat, I use 1/2 in tripple braid line. You might want to look into a danforth style with the sliding ring on the shank, if it jams you can pull from the opposite direction and the ring will slide down the shank and pull it out. Saved cutting the line twice for me

 

[barbosam]

Re: Anchor line length?

I am personally against using oversize line, I would stick to the 3/8 line. If a large swell comes under your boat and lifts the boat, line stretch will be you friend! If you use line that is to heavy it can snap taught and rip the cleat right of the boat and you'd probably crack a few teeth in the process. A properly sized line will allow the line it to stretch in these conditions saving the cleat, boat and your teeth. Trust me anyone who has moored a boat in a hurricane prone area for a long time will tell you that the boats that end up on the shore are the ones that use oversize line or chain only rodes.

Your boat is not heavy enough to stretch 1/2" line. 3/8" is rated to at least 27', its more than enough for your 20'er.

 

[themaniam1]

Re: Anchor line length?

barbosam said it right. You want line that will stretch. Three strand twisted nylon is a great anchor line and cheap. Stay with the 3/8" line. It will stretch and help take the shock when the boat is heaving and rolling on the swells and waves.

 

[Fireman431]

Re: Anchor line length?

All the above are correct. One thing that wasn't mentioned...

Have you ever hauled up a 15# anchor attached to 300' of line and 20' of chain? Get an anchor ball and save your arms and back. It's not for the one time you have to pull it up, it's for the times when the first 2 drops didn't hook and you have to do it again! Anyone who has ever used an anchor ball has never gone back to doing it manually. Even if you have a windlass, it's a great way to save the motor on that thing!

 

[themaniam1]

Re: Anchor line length?

All the above are correct. One thing that wasn't mentioned...

Have you ever hauled up a 15# anchor attached to 300' of line and 20' of chain? Get an anchor ball and save your arms and back. It's not for the one time you have to pull it up, it's for the times when the first 2 drops didn't hook and you have to do it again! Anyone who has ever used an anchor ball has never gone back to doing it manually. Even if you have a windlass, it's a great way to save the motor on that thing!

I forgot about that. If you don't use a windlass or an anchor ball, make sure you have a pair of gloves. By the time you haul all that up you will have blisters on your hands. Not to mention your hands will ache. It is a good form of exercise though.