Now that
Mareda has arrived (!!), the outfitting has begun in
earnest, and we have to make some firm decisions about equipment. This is in stark contrast to the decisions we've
made up to this point, which mostly involved flipping through the catalog and
saying “Cool ! Let’s add one of these !”
**note: I'm taking lots of photos of the commissioning process. See our Facebook page for all the latest photos and updates !
Starting
from the ground up, we've been thinking about anchors and chains this week.
The
standard offer for the SO 379 was a 16kg Delta anchor with 28 meters of 10 mm
chain and 40 meters of 18mm line.
(That’s a ~ 33 lb anchor, ~ 85 feet of 3/8” chain and ~120 feet of line). This all seemed a bit light to us, especially
for anchoring in the meteorologically-capricious Mediterranean. At one point, I tried to convince myself that
with a swing-keel we could get closer to shore and wouldn't need so much chain,
but for reasons I can’t quite put my finger on, I decided that this was dumb.
From technical
reviews and personal testimonies of friends, we knew we wanted a Rocna anchor. With Mareda's length of 11.3 meters and weight at just under 7 tonnes, the Rocna sizing charts suggested that an anchor of 15kg
would be adequate (where “adequate” is based on tests in 50 knot winds with
associated surge and poor holding conditions).
The chart indicated that 8 mm chain would suffice for our boat with such
a Rocna anchor. For the SO 379, 10mm chain
and windlass is standard, so we felt good about being over-spec’d (if that is,
indeed, the case).
But no one
said anything about the length of chain required. The basic rule (which of course has many
variations) is that you want to put out a length of chain that is 4 times
greater than the water depth at high-tide.
(Example: moor in 3 meters of water, put out 12 meters of chain). This all depends, of course, on the
conditions in which you anchor. An
interesting rule-of-thumb I saw recently: winds of Beaufort 3 = 3 x chain length; winds of Beaufort 4 = 4 x chain
length, etc., etc.
After
searching through numerous web-sites and talking to friends who know the Med
well, we decided that 40 meters of chain was the minimum for the Med. If 40m is minimum, I thought, why not go for
50, just to be safe? When I mentioned
this to Patrick, he turned on his best sarcastic voice and said, “Yeah, great ! and Hey! Why not 60?
Why not 75? What the heck… let’s
make it an even 100 !”
Slinking
back to my office, I started thinking about it.
Why not more? That’s when it
dawned on me that there must be limits, real limits, based on weight (and not
on snitty, financially-motivated comments from one’s husband). How much does all that chain weigh? When does your boat start to become nose-heavy? And what about the windlass? If you've deployed 100m of 10mm chain, is
your windlass strong enough to pull it up?
Easy stuff
first. 10 mm chain weighs 2.25 kg /
meter, giving us 112.5 kg for 50 meters.
Medium
stuff next: The windlass (Quick Aires
1000 W) has a working load of 120 kg.
Its maximum working load is more than double this, but we don’t like
pushing electrical / mechanical devices into the red zone, do we? So 50 meters of 10mm chain is getting quite
close to the working load. Add a 15 kg
anchor and we've gone past it. Granted,
the situation where you would have 50 meters of chain and the anchor hanging
through the water column all at once is rare and you could push the beast hard
for a short period of time, but you just never know, do you?
Hard stuff
now: When does the boat start to get too
nose heavy? As with most hard questions
in life, the difficulty lies in defining the question. What does too
nose-heavy mean? The only advice I could
find on this was “sail the boat with the
weight in the nose, then move the weight to the center of the boat and see if
she sails better.” Humph.
I’m still a
bit at a loss as to how to approach this one.
The standard equipment for the SO 379 gives 79 kg versus the 112.5kg we
want. The difference is peanuts, right? Let’s just assume (because I like the answer
I get when I do this) that the architects have given us a safety or performance margin of 2
relative to the standard weight they propose, which means that we could go up to
158 kg without getting too nose heavy.
Since we’ll be well under this mark even with 40 meters of 18mm line
attached to the chain, all’s well. With
time, I’ll convince myself that I feel comfortable with this.
In the end,
we decided to go with 40m of chain and 40m of line. Patrick triumphantly pointed out that this
was the decision we had come to before I did all these calculations. But what
else was I supposed to do with a cold rainy afternoon? (I’ve had other rainy-day inspired fits of
calculations, including rudder angles and hull speed. It rains A LOT in Brittany…)
So our
principal mooring will look like this:
- Rocna 15kg
anchor
- Articulated
Kong junction between the anchor and the chain
- 40 meters
of 10mm chain
- 40 meters
of 18 mm line, connected to the chain with a splice directly onto the chain (if
the 18mm strands fit through the 10mm chain links… to be determined shortly).
- A double
bow roller, which the Jeanneau dealer says has been reinforced after the first
models had problems.
- A snubber
- Depth marks
on the chain and an “aide memoire” of what the marks mean in the anchor locker. I think I’ll stick with my spray-paint
technique. You have to re-apply the
paint every year, but it’s quick and easy to do.
- The 2nd
anchor: a 12 kg FOB with 10 meters of
8mm chain + 20 meters of lead line. I’ll
attach another 20 meters of line to that when we go into the Med. After 2 years of sailing around northern
France, the Channel Islands, and northern Spain, we've never needed the 2nd
anchor, but then again, we've never had a boat we could beach before, either !
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| Our high-tech chain depth indicator system. |
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| Our memory aid of what those colors mean ! |
