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Old 10-25-2012
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Advise on Weight & Type of Anchor for Islander 37

The Anchor is completely missing. along with lead chain and anchor line.

I did some searching and did not find a lot.

I assume, a Danforth anchor type would be a fair choice. The weight of the I37is 14.9 K. I did see that some the anchor weights for up different lengths but think these were for power boats.

I guessing, 50 to 75 lbs anchor weight, 6 ft. lead chain, 150 ft. of 1/2 inch nylon line.

I may need a 2nd anchor, guessing, 40 lbs., 6 ft chain, 150, 3/8 line.

If I'm off, let me know. I saw a I-37 set up this way for sale,thought that I might copy cat what they had but not sure.

Avery
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Re: Advise on Weight & Type of Anchor for Islander 37

I have a similarly sized boat. My main anchor setup at the moment is a 16kg/35lb Delta and an all-chain rode. I felt the 16kg Delta was a bit light and I wanted to get a new generation anchor so I upgraded to a 20kg/45lb Mantus. I haven't put the Mantus on yet as I will have to modify the bow roller a bit to make it fit. I have no doubt the 20kg Mantus is a much, much better anchor. I would think the same setup would be ideal for your boat (20kg Mantus and all-chain rode). 6 feet of chain really isn't enough, no matter what anchor you go with. Have a look at the threads and videos on new generation anchors before you decide on a Danforth.
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Re: Advise on Weight & Type of Anchor for Islander 37

Boy. Where are you going to anchor? Mud bottom Danforth can't be beat. Unless you are out for a 180 degree wind shift. Danforths don't reset well under those conditions.

I went through Hurricane Irene last year in Oriental (actually Whortonville) NC. The eye and 110 mph winds with a 10.5' storm surge. I had a Lewmar hook, with 6' of chain and 1/2 nylon as one set. I had 90' of heavy stainless steel chain and a 55 lb Rocna as the other. The 1/2 line broke and I lost the Lewmar. Rocna held. It was a 7000 lb Cal 9.2.

So 1/2" line isn't strong enough. If you want to be absolutely sure use all chain.

And to answer. 3 Anchors. A lunch hook with light line and a small danforth. A large danforth and a hook or a Rocna (expensive but worth it) and either all chain or 20' of chain and heavy nylon line. Here's a chart, it says 3/4 three strand nylon has a strength of 11,000 lbs. (there's a formula which accounts for all anchor stresses but hey, I'm an artist...)...err HEAVY.

Danforth- worthless on a rock or hard bottom. Hook-ok but not great in soft and hard, good in rock. Rocna-good anywhere.

NOW- I have a question. First do my fellow sailors agree with my NC taught opinions. 2nd and my pressing question is CQR anchors. I have two 45 lb at the moment. My HB40 and my Tartan both came with them. What is your experience with a CQR?
3 Strand Nylon Rope
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Re: Advise on Weight & Type of Anchor for Islander 37

What area are you in?

Anchor choice depends on bottom. The new generation anchors hold very well universally in most bottom except grass.

Get a Rocna or Manson Supreme as your primary. Jury still out on Mantus as its new although it looks like it may become an alternative. All three "new generation" anchors have similar shapes and abilities. You actually should laso have a backup anchor on bopard also and I would use the Danforth for that or the Mantus (I have one as a backup because it can be stowed apart.)

You should also have at least 30 ft of chain on the rode. Do you have a windlass of any kind?

We carry a 20kg NZ Rocna as our primary with 90 ft of 3/8 G4 chain and 350 ft 9/16 rope.
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Re: Advise on Weight & Type of Anchor for Islander 37

Quote:
Originally Posted by daledog View Post
... The 1/2 line broke and I lost the Lewmar. Rocna held. It was a 7000 lb Cal 9.2.

So 1/2" line isn't strong enough. If you want to be absolutely sure use all chain. [/url]
Do you attribute this to chafe causing the line to part?

I find it hard to believe the pulling forces alone caused the line to part. One of the benefits of three strand nylon is its ability to stretch 50% before parting. Your rope should have had approximately 7,500 lbs. tensile strength, almost enough to lift the entire weight of your boat out of the water.

I survived a brief period of 70-100 mph winds on 200' of 1/3" three strand nylon with a danforth-style anchor and 6' of chain. The rope held fine, although I could feel it stretching. I have since picked up a 25# CQR plow-style anchor and a larger 20# danforth-style anchor, both of which will be secured by 200' of 1/2" three-strand nylon and 6' of chain.

Finally, to the OP, I am not sure you need to carry around everyday ground tackle sufficient to withstand sustained hurricane-force winds.

Last edited by jameswilson29; 10-25-2012 at 08:34 AM.
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Re: Advise on Weight & Type of Anchor for Islander 37

Agreed you don't need to carry a storm anchor when daysailing. Cruising is different.

As for the broken rode, I had firehose for chafing. I didn't put her out, I was in Maryland. A friend did and he's very cerebral. He figured 8:1 would be good, but he didn't figure for storm surge. he put out 80' of rode on the Lewmar and 80' chain on the Rocna. When the surge came thru, something had to give....I'm glad it was the line...
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Re: Advise on Weight & Type of Anchor for Islander 37

Daledog.....

Quote:
A friend did and he's very cerebral. He figured 8:1 would be good, but he didn't figure for storm surge. he put out 80' of rode on the Lewmar and 80' chain on the Rocna.-Daledog
Well he may be cerebral, but he forgot 3 important facts,,,bow distance, tide change and storm surge.

80 ft of rode assuming you are anchoring in 6 ft of water is not 8:1. What most people forget is to also add the freeboard. Most boats freeboards are at least 6 ft so that in 6 ft that would make 12X8 or 96 ft of rode. If you add the 6 ft tide change and surge, and these are all very minimum, you need 18X8 or at least 144 ft of rode for 8:1.

I am sure you were in deeper than 6 ft or youd have been in trouble when the reverse winds came and blew the water out youd have been aground.

You should measure the true distance from your bow roller to the water to add to the depth when determining scope

You also should comnsider the normal tide change and predicted strom surge and also add to the initial water depth calculation before determining rode length.

It appears youre scope ratio at 6 ft depth was more like 4:1 not nearly enough/

Dave

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Last edited by chef2sail; 10-25-2012 at 10:35 AM.
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Re: Advise on Weight & Type of Anchor for Islander 37

Quote:
Originally Posted by HighFly_27 View Post
The Anchor is completely missing. along with lead chain and anchor line.

I did some searching and did not find a lot.

I assume, a Danforth anchor type would be a fair choice. The weight of the I37is 14.9 K. I did see that some the anchor weights for up different lengths but think these were for power boats.

I guessing, 50 to 75 lbs anchor weight, 6 ft. lead chain, 150 ft. of 1/2 inch nylon line.

I may need a 2nd anchor, guessing, 40 lbs., 6 ft chain, 150, 3/8 line.

If I'm off, let me know. I saw a I-37 set up this way for sale,thought that I might copy cat what they had but not sure.

Avery
An old rule of thumb is that one's anchor should equal, roughly, in pounds the LOA of the yacht. I.e., a 37 foot yacht should have an approximately 37# anchor, or with Fortress type anchors, the functional equivalent. In terms of chain/rope rode, the rule of thumb was chain equal in weight and length to the LOA of the yacht. Hence with a 37 foot yacht one would have 37' of chain weighing, roughly, 37#--e.g. 5/16" proof coil chain at 1# per foot. As for the size and length of the rope rode, size should be matched to the chain and length depends upon the depth one is likely to be anchored in measured from stem-head to bottom at high tide. For "storm" conditions, the suggestion was to double the effective weight of the anchor.

We have relied on minor variations of the foregoing for 40+ years without undue difficulty with due regard for bottom conditions, hence type of anchor used, and scope which I prefer be at least 5:1, stem-head to bottom at high tide. For short stops we have gone as little as 3:1 although I'm not comfortable with that and for more than an over-night prefer 7:1.

FWIW...
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Last edited by svHyLyte; 10-25-2012 at 11:35 AM. Reason: Correct typo
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Re: Advise on Weight & Type of Anchor for Islander 37

If you can afford it or if sometime in the future you are planning a carribean voyage .....just go out and buy a ROCNA ....Rocna Anchors // Rock Solid » Rocna Anchors ......they are the best of any anchors with out a doubt and the only one I would buy new .....
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Re: Advise on Weight & Type of Anchor for Islander 37

as for chain and anchor rode ........37 ft boat ...length of boat plus 50% of 1in chain and 150 to 250ft of anchor rode depending on where you are locally ......layout scope for anchor rode 5 to 1 [less than 15ft of water]
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