Many years ago, a salty old retired USCG chief taught me the rule of thumb that
you should have one pound of anchor and one foot of chain for every foot of
boat length.
I decided this current discussion would be a good time to double check that
rule of thumb.
I was pleased to find that Boat/US mAkes the same recommendation. Fortress
anchor calls for less weight in their aluminum anchors, and a relatively short
length of chain to help in setting the light anchor. But for steel anchors and
a 30 knot wind, Fortress also says the pound/foot/foot system is recommended.
Mark, I have to agree that 5/8 anchor rode is more than you need.
I also use 1/4 HT chain and 1/2" 3-strand for the anchor rode on my 38. I do
have 65' of chain in each rode and oversized anchors, because once the anchor
is down I want it to stay down.
According to what I found this morning, the load on a typical sailboat at
anchor in various wind strengths is:
@15kt. @30kt. @42kt. @50kt
30'. 175#. 700#. 1400#. 2800#
35'. 225. 900. 1800. 3600
40'. 300. 1200. 2400. 4800
Max working load of New England Ropes 3-strand is 1/3 of break strength (I
prefer to use 25% in sizing the line myself). Break strength for various sizes
are:
3/8. 4400 #
1/2. 7800
9/16. 9400
5/8. 12,200
So 1/2" rode should be adequate for a 30' boat in almost 50 kts, a 35' boat in
42+, or a 40' boat in well over 30 knots. I will almost always deploy a second
anchor if the winds will be 30+.
As far as what chain to use, the working load for various size chain is:
Proof coil. HT (G4). BBB
1/4. 1300. 2600
5/16. 1800. 3900. 3800
3/8. 2650. 5400
So one could use big chain to increase catenary and help the anchor stay set,
but 1/4HT is strong enough for up to a 40' boat in any reasonable conditions.
Rick Brass
Sent from my iPad
> On May 12, 2014, at 23:42, Jim Watts via CnC-List <[email protected]>
> wrote:
>
> Considering I use 1/4" HT chain and 1/2" nylon for Shift, I have to agree.
> 3/8" nylon would be appropriate to give enough stretch with strength.
>
> Jim Watts
> Paradigm Shift
> C&C 35 Mk III
> Victoria, BC
>
>
>> On 12 May 2014 17:59, Chuck S via CnC-List <[email protected]> wrote:
>> Mark,
>> Sounds like you are building a hurricane proof anchoring system? 5/8"
>> nylon is hard to get onto cleats smaller than 10". Just sayin.
>>
>> Following Chapman's, I tried 5/8" docklines and found I could never get them
>> over my 6" and even 8" cleats. I use 1/2" nylon three strand twisted for
>> lunch hook and 1/2" stretchy double braid for tougher situations. 36' and
>> 11000#. Gave more than 200' of 5/8" nylon docklines to my brother-in-law
>> for his clamboats.
>>
>> If you are committed to your present system, you should check out Wichard
>> for amazingly strong schackles in small sizes. Their SS is the strongest.
>>
>> Chuck
>> Resolute
>> 1990 C&C 34R
>> Atlantic City, NJ
>>
>> From: "CNC boat owners, cnc-list" <[email protected]>
>> To: "CNC boat owners, cnc-list" <[email protected]>
>> Sent: Monday, May 12, 2014 1:52:33 PM
>> Subject: Stus-List Shackles and chain
>>
>>
>>
>> Needed to replace the chain and shackles on my anchor - the existing
>> shackles needed to be cut off with a cut-off blade (totally corroded).
>>
>> Bought 16' of 5/16 galv chain to add to connect the 27lb Kingston plow
>> anchor and the ~250ft of 5/8" rode.
>> But I was surprised to find that I couldn't fit the U of a 3/8" shackle
>> (or even a 5/16") through the 5/16 chain. Everything I read said I
>> should bump up the shackle one size from the chain to maintain working
>> strength - but given I couldn't fit the ends of the U through the chain
>> links I had to use 2 shackles on the anchor --- one with the pin through
>> the anchor and a second shackle reversed with the pin through the chain
>> link.
>>
>> Is that normal? I tried chain a 2 different locations with same results
>>
>> Mark
>>
>> --
>>
>>
>> There is no cure for birth and death save to enjoy the interval.
>> - George Santayana
>>
>>
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