Friday, May 22, 2015

Tandem Anchors IV -- the Wemar Anchor

This is a perfect example of what you get reading reviews in magazines that accept advertising. The month Wemar started advertising, Sail Magazine reviewed this bit of foolishness that does not function AT ALL, and nominated it for an award. Just pitiful.


In this test they pretend to show veering... but the secondary is not set and they have eased around very slowly. Shows nothing.
https://www.youtube.com/watch?v=l11rjDI9eSk

 




Then they show this video of retrieval. Notice that the primary never set, at all.

https://www.youtube.com/watch?v=O-or9ByglfU


On the Web site they have only these 2 lovely failures:


This time the secondary is not set.

Tandem Anchor Classic 


 And this time the Primary is not set, or rather I think it has tripped (it is off-line in the direction of the pull).


Tandem Anchor Classic

 
 
Why would you post 4 pictures of failure? Because they had no successes? Or is it because the target buyer has been identified as completely ignorant of anchoring? I do know why Sail Magazine nominated this for an award.

Saturday, May 16, 2015

Tandem Anchoring III

Now that the water is warm, it's time to move into the shallows and test some theories. Want to toss in your ideas? Maybe learn something, even something that over turns the conventional wisdom? I've learned a lot in just a few short sessions. I would love the input of local sailors, and anyone that would like to join me in Deale for testing, even just to observe, please leave a comment.

This time I took to the beach with a Mantus Dingy anchor, in addition to my Claws and Guardian.


A fabulous new-design anchor, penetrates many bottoms and is absolutely stable in direction changes. Definitely my new dingy anchor! Why no roll-bar? Mantus feels it is not needed for dingy use, though it will stay on the big anchors. For my testing, it is a fair surrogate for Rocna, Manson Supreme, and Spade. 

 
 Still tripped when rigged as single-line tandem rig in sand. 

 


Still will not work with a Guardian. Lifted right out of its set and into the air.


 But mighty when paired with the Guardian in a V.
  


 The only combination we simply could not budge. All others could be dragged with little to moderate effort.

Tuesday, May 12, 2015

Magic

Is it any wonder that as children, humanity saw magic in the skies?


But wouldn't we have outgrown the need by now? I guess it's comforting.

Sunday, May 3, 2015

The Folding Rule Method



Every spring, as masts are plopped back on decks, I see folks out there with rig tension tools. I hear folks complain that the tool does not cover the size they need. As an engineer that has been responsible for tuning structural cables up to 1 1/2-inch in diameter, we don't need no toy tools. This method works for ALL sizes, since stretch is a steady function of % breaking load. 

Yes. the tools are handy, particularly for fine tuning. For big wire, there are still other methods... but that is another chapter (hint: use a scale and pull to the side, using simple trig. On bridge wires we just use gravity and sighting.).

This specific wording is borrowed from Seldon Spars

_____


The following materials are required:

  1. A 2 metre long measuring rod (a folding rule is recommended)
  2. Adhesive tape
  3. Vernier calipers

• Start with the cap shrouds only hand-tight. The rig is stayed with the lower shrouds and the forestay and backstay.

• Tape the upper end of the folding rule to the starboard cap shroud. The lower end of the folding rule must be approximately 5 mm above the upper end of the wire terminal.Measure the distance between terminal and folding rule exactly. This is index 0, let’s call it point A.

• Tension the starboard cap shroud until the distance is A + 1.5 mm between the terminal and the folding rule. Measure using the vernier callipers.

• Leave the folding rule attached to the starboard shroud, and move across to the port side and tension the shroud rigging screw the equivalent amount.

• At intervals, check the starboard side to see how much
the folding rule has moved from the end terminal. When there is a gap of A + 3 mm, the cap shrouds are tensioned to 15% of the breaking load of the wire (3 x 5% = 15%).


If the mast is not straight, adjust the lower shrouds, intermediate shrouds etc. There is more information on this in the chapter dealing with your rig type.


The folding rule method can be used on other stays, such as the backstay and forestay (without jib furling system). It can also be used for Dyform- or rod rigging, but please take the difference in stretch into account compared to 1 x 19 wire. 


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Stretch per 2 meter at 5% of breaking load
1 x 19 wire                  Dyform                      Rod


                                       1 mm                     0.95 mm                  0.7 mm

Tuesday, April 28, 2015

Honey, They Shrunk the Captain!

Touring the Annapolis Spring Boat Show and researching for an up-coming article on access for decrepit (bad knees, like me and my wife, and an increasing number of friends getting hip and knee replacements) sailors, we came across some good things and some unbelievable things. Honestly, how many folks get $500,000 together for their dream boat before their knees start to hurt? Not so many that the designers should ignore the reality. Or like me, the knees are fine when you buy the boat, and then a lifetime of vigorous activity starts to catch up with you.

And some things are just funny. This really belongs in Disney Land in the "Honey, Who Shrunk the Kids?" theme area. The seat is 8 inches too high and 8 inches too far back; as it is, the driver has no leverage on the wheel. At the very least, it needs a foot rest or fold-down runt board. And we saw this same problem on every single helm seat. Comically unsuitable for a long turn at the wheel.


Kinna reminds me of this, early in our ownership with a temporary runt box in place. It worked, giving her something to brace against.



On Shoal Survivor we eventually added a proper runt step, and it is still a little tall for my daughter (20 years old, but somewhat vertically challenged). Our feet now touch the floor, we have leverage, and an added storage spot to boot. And the wood was salvage from the sole replacement on a Prout.


                                            http://3.bp.blogspot.com/-EPAI9J_zk5Q/UbTqhfngSbI/AAAAAAAACDI/j6eedz3iOnw/s1600/Up-graded+runt-step.jpg

Reefing a Blad Jib--A purpose for the PDQ Self-tacker?

I've never really liked the self tacking jib on the PDQ 32.
  • Not enough power in light winds
  • No shape off the wind (poor twist control--traveler needs to be semi-circular to work)
  • Becomes fuller when rolled in stronger winds
  • Does not feather well
While paddling around the harbor in Deale I saw this:


It is not a simple matter of adding reinforcement, reefing eyes, and a clew ring; this sail is much flatter. I also wonder that the big roll of reefed fabric won't ruin the airflow off the bottom, though the problem will be less if the foot adjustment is less. In my case, I would probably not change the hoist, as in this example because I can still roll it up, but simply add a clew ring that would allow me to use my existing inside genoa leads.

And since I would rather not have to lower the sail to reef it... how in the heck do you tie up the bunt and attach the sheets? On the other hand, the clew should be about the same height as my genoa when rolled up just short of the mast, and I can just reach it from the cabin top. Certainly a short pendant would make it work.

Something to ponder. A simple project that would be synergistic with the 3rd reef in my main, the inside tracks, and longer transoms, improving strong wind weatherliness. A DIY project? I've designed and sewn sails before. Hmm...

Saturday, April 18, 2015

Carbon Filters--Winterizing and Re-Use

Many seem to be of the belief that that filters benefit from being replaced each year, regardless of the through put. Simply not true.

Pre-filters. While I like particle-only filters, particularly the the DIY Baha Water Filter I wrote up for Practical Sailor, I do like the convenience of hose end carbon filters. They are so easy. But after  a year the flow is often down to a trickle. But that is NOT because the filter is ruined, but rather because the hose shed some algae and clogged the entrance strainer, something that is easily cleaned in 30 seconds. Just store the filter dry over the winter and flush with tap water in the spring.


 Carbon Block Filters. Same thing. Store them dry at home and re-install in the spring. They will last until either the requisite number of gallons is passes (more if the chlorine is low, which it is) or until the flow is reduced. I've done this numerous times, and the water is always bottle-fresh.

---

(Bear in mind that I clean and dry my water tank every fall as a part of winterization. It always seems simple to add just a little extra chlorine on the last fill, use it dry, and then stir it around a bit and suck it dry with the shop vac. Nothing grows in a clean, dry tank. You wouldn't put dishes away dirty, would you?)



Wednesday, April 1, 2015

Kayaking in March

It's about the details.

A dry suit helps a lot. A bit of a struggle, worming the arms in and fitting all the seals, but...


ultimately well worth the struggle.



Extended transoms for boarding are nice...

and the after-paddle swim makes it perfect (the water is 36F). Just testing out the suit, but swimming was actually pleasant.


Very cool... figuratively speaking.

Monday, March 30, 2015

Tandem Anchoring II

A few weeks ago I spent an afternoon at a gravelly beach playing with 2-pound Lewmar Claw and Fortress Guardian anchors, without insrumentation, just to learn about tendencies.

Claw-Claw Tandem. Good holding, but in a straight line only.You do need 2x scope for this to work (the primary sees 100% of the lift but only 50% of the horizontal)


Claw-Claw Tandem Veer. As soon as the angle approaches 15 degrees the primary rolls. Though it will reset if the secondary drags far enough and the scope is long enough, much of the time the primary effectiveness is greatly reduced. (On the trial using the tripping hole the primary became pinned on its back like a turtle in the street.)

Though some have suggested the secondary helps hold the primary down, preventing roll-out, this is pure urban legend. In EVERY trial the primary rolled, which this anchor never does on its own.

Claw-Guardian Tandem Straight. Even though we set both anchors separately (which may not actually happen) as soon as we pulled hard the primary lifted right out of the bottom and was suspended inverted! It became a useless kellet.

Claw-Guardian, joined near shackle. Better, at least the primary stayed in the bottom.


Claw-Guardian, separate rodes. Very stable and strong. We could actually horse around on this one. The Claw helps stabilize the direction of pull on the Guardian, which very solid. This combination could not be dragged, but...

Claw-Guardian, 2-rodes, fouling. ... It can foul if the wind rotates back (rode is under shank). Additionally, if a fiber rode is used...



... It can cut.

So, what is the optimum rig? We still have a lot of testing to do.
  • The tripping hole is a big mistake.
  • Rigging with 2 rodes is strong and stable if you can anticipate the wind shifts. But multiple 360s is a risk of fouling and cutting; A Bahamian Moor would be better.
  • Conventional tandem rigs have limited value if the wind is going to change.
I will be doing on the water testing soon, in mud and sand. I'm also waiting on a scoop-style anchor (Mantus Dingy) as it is far more common that the Claw.

On the gravel beach we will test:
  • Same combinations, substituting scoop for claw.
  • Bahamian moor. What happens when the anchors come together, after dragging?
And on the water we will test:
  • Same combinations, sand and mud, instrumented.
  • Full size combinations (just the more useable ones) for ease of deployment and retrieval.


Comments are welcome. If you have combinations you would like tested, make a comment!

Friday, March 20, 2015

Tandem Anchoring

(Yup, another Practical Sailor project in its infancy)

While a single large anchor of modern design is generally the best answer for every situation, there are times when something more is needed. For a Chesapeake sailor the problem is a soupy bottom that won't hold anything and a fast approach squall with a 50-knot gust front. You don't want to re-anchor elsewhere:
  • Is anywhere very nearby better?
  • My anchor is already well settled in; moving will very likely mean a weaker set.
  • I've got 10-20 minutes to do what ever I'm going to do.
You also don't carry any special gear for storm anchoring. Like most Chesapeake sailors, you've got a Delta, Rocna, CQR, Mantus, or Manson Supreme on the roller, and a Fortress in a locker somewhere. The Fortress is your "storm anchor," but really, it's for kedging off mud. It has only a little chain, it's light and easy to row out (in a pinch you could swim it out on a PDF), and it has terrific holding power in soft mud.

There are many possible ways to rig tandems.Here are just a few I'm playing with.

______________


I've been playing with these on the beach an on my boat, so I'm not guessing, not entirely. But I have a lot more measured testing to go.






Secondary rigged to tripping hole. Terrible idea. If the tripping hole does not rip out (it has been reported--it is not made for high load), it will make the primary trip when the wind shifts and prevent re-setting; I've tested this, don't even try it.








Secondary rigged to tandem hole. Better. This is what Rocna suggested, and it is doing better in my testing. But
  • You need a Rocna
  • You would need to lift the primary to add it, which we don't want to do. 
  • It is a bugger to know if BOTH anchors are set, not fouled with chain, and that the primary set first. 
  • It's not much good in wind shifts. Better, but not much.
  • The second anchor must be smaller or it trips the first.
Could you drill your own Tandem hole? Possibly, but it will start corrosion and eventually weaken the anchor... though that depends on where you drill the hole. I wouldn't drill the shank, but it might be safe to drill in the tail of the blade in a non-structural area. Interesting. Could you chain the tandem on? Folks do it, but I bet the chain moves around, and if you chain it to a brace, how strong is that?








Secondary rigged near primary shackle. This is what you might do if there is no tandem hole. Not quite as good, same problems. Additionally, if the primary is not buried, the secondary rode can foul, and since we set them on the same rode, we can't be certain that it is (the secondary might have grabbed first and held the primary on its side).

In these first 3 cases the scope must be ~ 2 X normal scope, because the lifting force on the primary is 100%, but the pull is only 50% (the rest is passed to the secondary). If the secondary is Fortress-type, they are all hopeless; the secondary tension lifts the primary out, since the secondary is holding 70-85% of the load--the Fortress generates its holding without dragging (it is stiffer).










Secondary rigged 1-3 boat lengths up the rode. This can be done without lifting the primary, as I have done many times. Simply row the secondary out ~ 20' past the primary, set from the boat, then come up on short scope and connect the 2 rodes with a soft shackle. The secondary rode must terminate here to avoid tangles (we clip a long polyester line to it during setting and recovery to make things easy). The primary will not be fouled by the secondary rode if is set deeply in soft mud, which should be the case. You know that both anchors are set, because you power set each separately.








And what if the secondary is a Fortress? Since this is what we have, what many of us have, and what I have used for years, we need to understand how to use it. It turns out that this is NOT trivial change. In fact, because of its greater stiffness, it changes the math considerably. Since the Fortress has higher holding power in soft mud than the primary, most of the load is on the Fortress. The primary, on the other hand, serves more to keep the load in-line with the Fortress. On the beach, at least, this is by far the most robust rig.

Unlike the first 3, the scope requirement on the latter 2 rigs is not effected because the rodes are sufficiently separated. 7:1 should do fine.

_______________

So why is this last rig not the obvious answer? Several reasons:
  • Tripping. If the primary is not buried, the rode better not slide over it. Cutting is also a concern with a fiber rode.
  • Deploying. Actually, not really. You only handle one at a time. The primary is already down. Setting and retrieval are a matter of either extending the rodes to the boat (easy) or clipping a temporary extension while setting and retrieving (better).
So there is more testing to do. I'm pretty certain that the 1st and 3rd rigs have nothing going for them, based upon beach testing; the 1st is a disaster (might as well leave the second anchor in the locker), and the second is less stable than the 4th, simpler but more physical to deploy and less reliable (you can't know which anchor set). All of the first 3 can leave the primary hanging in mid air if the secondary holds and the roll out. I need to study the behaviors in mud.

Yes, I have been advised that small anchors do not scale up. I've had the small anchors for 20 years and I really do know how differently they perform compared to big brothers. But I do think the affects of geometry will scale up; bad rigging is bad rigging, and I expect the small anchors will be even more vulnerable to mistakes, which I like.

Fun stuff. I will play on the beach. I will play in the shallows. I will anchor my boat (full scale tandem) over soupy mud and pull these mini-tandems with my primaries, taking force measurements and diving to watch. A lot of playing in the mud this summer!

________________________________________________________

Comments PLEASE! Do you have a favorite tandem rigging you would like to see tested? I will add it. I will be using Claw, Guardian, and Mantus anchors, since these come in small sizes and have close analogs at full scale. I will test in both firm sand and soup.