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Advise on Weight & Type of Anchor for Islander 37

6K views 29 replies 14 participants last post by  Grumpymx 
#1 ·
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
 
#2 ·
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.
 
#3 ·
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
 
#5 · (Edited)
... 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.
 
#4 ·
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.
 
#6 ·
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...
 
#7 · (Edited)
Daledog.....

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

Dave
 
#8 · (Edited)
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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#11 ·
Coupla thoughts.

1-If it doesn't have the Islander logo on it, it really shouldn't be on the boat. (VBG)

2-Got an anchor locker? How big an anchor can you stuff in it? (Seriously.) And

3-If you can lift it, the anchor is too small. Get the biggest one you can grunt up.

Other than that, everything is a lunch hook. Everything works on some bottoms not others, everything is "enough" until the wind and waves get strong enough or the anchor doesn't hold in a particular bottom.

So I'm really serious when I suggest, the biggest and heaviest anchor you can work with, regardless of what type it is. Then if you want a lunch hook to keep on a bow roller, that's something else again.
 
#12 · (Edited)
HelloSailor,

So, I'm Really Serious.

I have found several (used) anchors for sale, and some of them are larger ones. Daily use, I can handle a 44/ 60 lb. anchor. I'd use the hvy. weight anchor (70/ 100 lb.) as my back up (storm) anchor. Reading here, important to buy Rocna or Manson or ???? anchor to hold the boat (for real). So, pay more for a good anchor that really holds.

I Need 37 ft. of 5/16 or 3/8 high grade chain and 3/4 in. nylon (11K rated), say 150 ft. with 38 ft. of chain attached. I will double this amount with a 2nd rig for HD storm anchor. I should be able to withstand a storm this way, need to play out 144 / 150 ft of rode to allow for sea surge, etc. .
 
#13 ·
Highfly, the advantage of using one of the new generation anchors (Mantus, Rocna, Manson) is that you don't have to carry around a bunch of different anchors for different bottoms. Also, since they have much better holding power you don't need to exaggerate on the weight of the anchor. A 45lb anchor for your boat is plenty.
 
#14 ·
Just to "weigh" in I agree with most the posts here. You should see a common theme, buy a third gen. I really like the Spade with it's weighted tip as well as the Rocna and Manson. Buying a good all around is for sure the way to go. Don't skimp on that little thing keeping you off the shore!
As a note, you will find many CQRs for sale (or in the dumpster), avoid at all cost. They are the (by far) worst (yet popular) anchor ever produced
 
#15 · (Edited)
Yes, I have just read about the Use's of the different anchors in the 2012 West Marine Catalog.

Now, I know (just pointed out above) that I do not need a heavy weight anchor. I need a anchor (best design) to dig in .. on any type of bottom and hold. I read about the Manson Supreme & Rocna Spade. I read that they hold on 4 different bottoms. I'm zeroing in on -- Rocna 20, 44 Lb. # 9261652 about $ 699.00 or the Manson Supreme, has about the same specs. . I found the attaching gear too - 9/16, 3 strand (250 ft.) anchor rope with 20 ft. of 5/16 HT G4 chain at
$ 150.00. I'm writing this stuff down because I want to get it right the 1st time (to be reviewed).
 
#18 ·
On a more serious note, personally I (32', 14k lbs) like the 3-anchor approach - lunch hook, overnighter, storm anchor. I use the lunch hook most often: 8lb Danforth, 10'chain, 150' line. I then have a 22lb Bruce - good for where I am (mud) - 20' 5/16 chain, 150' 1/2" line. And then a 35lb Manson. I am saving up for the chain/rode, but it will be 30+' 3/8 chain, 200' 5/8 line.....
 
#19 ·
80 feet of rode is only sufficient in a storm condition if you are in 1 inch of water with no freeboard.
10:1, including freeboard is the minimum I would use for a storm (and figure tide and surge predictions as well).

You and your cerebral friend got lucky you only lost an anchor.


Your Islander has lots of reserve buoyancy in the bow, and ground tackle is your primary insurance (the actual insurance is the last resort). 45 pounds of primary good anchor - and 100 feet of chain with 100 feet of rode would be my suggestion.

If you don't have a windlass you can carry a secondary (the danforth you have) with minimal chain and 100 feet of rope as a lunch hook from when you are lazy, or no wind is expected. That's also a good stern anchor to drop when needed.
 
#21 ·
Note: I have Not bought my anchors yet. I was talking about the Danforth because it's the 1st anchor that I read about, have not bought anything. My Islander 37 is being delivered on the 31st. The I-37 will not be in the water until April 2013. I will focus on all the (1st) important items -- needs Rudder repaired, needs 4 in. x 4 in. hole repaired that was cause by a accident (Hurricane). Next, go over the boat... top to bottom and make a do list. I talked to the owner a couple days ago. Now, I d know the boat faily well (thru him). He thinks it's ready to go after the rudder and the small hole is patched, he spent $ 20K on the boat (engine, drive, etc.).

Please bear with me, new guys to sailing .. ain't too brilliant. I have a note book 3/8 inch thick, started the 20th of Oct., the day I bought the I37.

Thanks,

Avery

So, I'm zeroing in one, two or three anchors I need for my boat. The Islander was sold without it's anchors. The Modern Designs are the answer, according to everyones vote's (above) with Mantus, Rocna and Manson Supreme as best choice. I'm really green and smiling.. when I read about the -- lunch, evening, storm anchoring (smiling, like a dummy) but I get the concept.
 
#22 ·
highfly, be very careful with the rudder. Once a rudder starts to fail, it fails in very clever ways, sometimes years down the line. If there is any penetration of the skin, any slight hairline crack, any failure of the seal where the rudderpost enters the skin, then water gets it, worked by the pressure from thermal cycling. Once the core gets wet it can take an incredible long time, months in hot dry air, and still not dry out. Then the problem is that the stainless rudder post, usually welded to a flat iron armature in the rudder, starts to corrode. Not simple rust, but the anoxic crevice corrossion that damp stainless suffers from, which is pretty much invisible until the day it suddenly fails.

You want to make Real Damn Sure that rudder is dry, and if necessary, rebuilt. Rebuilding them is not cheap, and there aren't many places who'll even touch the job. OTOH if you'll always be someplace where the loss of a rudder and a tow isn't a problem...there's less to worry about. You'll find other threads about rudders, failure, damage, if you want to pursue that someplace, rather than go OT here.
 
#23 ·
I should have specified -- the rudder was damaged in the storm. What happened, the boat broke free from it's morring. 2nd part of story, the boat keeled over (somewhat) when the tide went out. When the salvage crew righted the boat with air bags, the rudder was at a angle. The rudder was damaged, about 2 foot was busted off the bottom. I looked at the rudder on Monday. I had the yard master verify rudder travel as I ran the wheel through full travel (left/right). He did not see any sign of canting or anything wrong from a visual standpoint. I'm Not sure yet, the shaft may be bent. I will know this when I have time to check the rudder out (100%) at home. When I check it again, I'll straight edge & measure it as needed to verify condition. After removal, I'll determine if it's repairable or not. I have found -- 1 or 2 places that are highly recommended; will repair or replace the rudder for (est.) $ 1,000.00. I may do the job myself, capable of making/ repairing this rudder &, have a fully tooled shop.

Thanks for the Heads Up,

Avery
 
#24 ·
A fully tooled shop, that's cheating. (G)

Forigve me is this is old news but assuming the piece that broke off is gone, you may also want to track down abother I37 in order to carefully match rudder shape. If the shape is not 100% the balance will change and some of the Islanders had exceptionally fine balance, worth trying to keep.
 
#25 · (Edited)
I'm a aviation mechanic and built my own plane from plans in 1991. I did not realize that the Rudder was on boats were / or can be a Tuned Item. I'm going to try to find another I37MS owner and get rudder measurements. I did not pay attention to my rudder, to check if it had taper or is a straight run rudder from top to bottom.

So, I'm looking for another I-37 MS owner to let me know what the I37 rudder measurments are ____________ ? The boat needs to be out of water or measurement had been recorded before (when boat was in dry dock) otherwise it will be a little bit wet to get them (little joke).

I talked to the previous owner about the Rudder. He said, it's an effective Rudder, he had No complaint, including reverse. He said, he'd cut about 8 to 9 inches off the bottom. not return it to it's 100% size. I asked why, he said that the Rudder was always at risk with it's (nearly) 6 ft. draft. He was always at risk to hitting the bottom of the Rudder. The rudder was very effective and he had verified this (again) when he bought the boat in FL. He was caught in a storm back to Gulf Port, MS with a 50 knot winds and heavy sea conditions. I did not say anything but did get his point about the rudder at risk (6 ft.) and subject to getting hit all the time. I don't know if taking 8 or 9 inches off... was a good idea or Not ?!? I know in the aircraft repair world, I'd never be authorized to change one thing about the rudder (never) or anything else on a aircraft. However, aircraft have a fine line of balance (center of gravity & control response) and subject to crashing if you screw it up.

Information from yard master, he motored the boat home from Gulf Port to his yard in Biloxi with 2 feet busted off. He said, it worked OK, but he would not take it out in weather conditions. He thought that the boat would sail (motor) just fine to Panama City, FL. He said, I would save $$$ on the trucking expense and the cost of demasting the boat. I said, I would not chance it and wanted the boat 100% before it went anywhere.

So, I get your point and will make sure that the new rudder or repaired rudder is very close to the old rudders exact size & airfoil shape. I was sent a great article & picture of his new ( not for I37)rudder from two of the members, see my other post on needing a rudder repaired on Islander 37.

Avery
 
#26 ·
Oh, one of those guys who complains every time a pilot brings back an airplane in "used" condition. (VBG) No, seriously...you sound very much aware of the issues. The keel and rudder are just two airfoils (the hull actually is a third) on a boat and even now that there are computers, the art of tuning all three to make a boat sweet instead of a mule is partly black art.

I don't know about the I37, do know some Beneteaus are notorious for having a rudder that is deeper than the keel and as such, a real danger for grounding damage. I wouldn't want a rudder deeper than the keel, but I'd be loathe to chop one down. If I was going to tackle that kind of problem, I think I'd make the keel deeper rather than chop the rudder.

Consider, as you heel the boat the rudder effectively becomes shorter, it doesn't extend down into clear undisturbed water, and with some boats that means you lose steerage one you heel over too far. Steering balance, sail balance, these are all three dimensional multi-variable euqations on a boat, or four-dimensional as they also change with speed.

Some rudders certainly CAN be improved. With potential rudder post damage and fully two feet busted off, and no way to know if the internal armature was still firmly attached versus beginning to come off the post...Trucking would definitely be the more conservative way to go.

It is also possible that you might find a used rudder from a consigment shop or breaker's yard. I don't know any good lists but you might try Sailorman in Fort Lauderdale, there's another one in Tampa/St.P. I can't remember the name of, sometimes you get lucky and someone can drum up the part.

Or I suppose you could drop the rudder, ship it home by motor freight, rebuild it and then ship it back before sailing the boat home. Between shipping costs and time...trucking the boat home might be the way to go, so the rest can be done without any rushes or risks.

Having been up close and personal with the "professional" replacement of a rudder by a certain leading name company in that business, I can only say be careful. The difference between a certified aviation mechanic and a shadetree greasemonkey comes to mind. (G)
 
#27 ·
HelloSailor,

1st of all good advice & insight ref. I37 rudder.

I'm too far down the road in regard to motoring home or trucking it. I had the dropped mast down and the cashier's check is sent out. The boat needs TLC and I don't know the boat either.. it was a easy choice to ship it home. I see hours & hours of work to be done over a 5 month period. The boat will be parked next to my shop, 150 yards from my house.

Regarding the rudder, I will continue to gain information. Hopefully, I can connect with another I37 owner and get the measurements I need. Also, contact the larger salvage yards and see what comes up. From what I read.. the I37 Islanders are not that common.

Thanks a lot,

Avery
 
#28 · (Edited)
On my 35 foot 13000# boat, I have a 48# CQR, a 48# Bruce, a 25# CQR, and a smaller Danforth for a "lunch"anchor. My rode is 3/4" 3-strand nylon (have many hundreds of feet aboard) and a 60' 3/8" chain leader. I think the 3/8" chain is a must as are the over-sized anchors. There is no guesswork. They set, they hold. Screwing around with minimal sized ground gear is asking for trouble sooner or later. Next season I plan on buying a 45# Mantus and increasing to 200' of chain as well. Being able to sleep at night is important when you're cruising.

As far as a "storm" anchor, I always have my eye out for a Luke or equivalent "Fisherman's" type anchor for a good price. For odd grassy or rocky bottoms they work well. I used to have one on a previous boat. It saved my butt a couple of times. Wish I still had one. Probably a 75# would do on your boat.
 
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