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Author Topic: Roll bar anchors on bow roller Rocna Flix  (Read 27126 times)

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Stu Jackson

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Re: Roll bar anchors on bow roller
« Reply #30 on: April 17, 2009, 08:16:29 PM »

Braxton,

Emergencies are what you make them when it comes to anchoring.  Weather forecasting is a very able tool to understand what's ahead of you.  In your cruising grounds you have a wide variety of conditions, and if you stretch your legs to the Gulf Islands and further north, you have even more.  I will rely on our experienced northern brethren to explain anything you need to know about "local knowledge."   :D  I'm glad to explain what it is I don't know, which exhibits itself on a regular basis.

The general consensus is simple:  deploy your "main" anchor all the time unless you actually believe the weather reports, and even more important, your own eyes and ears.  If you're ever gonna stop your boat, stop it right, the same way every time, as if you're gonna be sleeping all night even for a lunch break.

There is no such thing as "oversized," because that means you selected the wrong anchor!  And you already have recommendations about what Rocna to buy from those in your neck of the woods and planning to go further afield.

YOU have to balance your back, your windlass (?), your conditions and your expectations.

And design an anchoring system, not just some cobbled together arrangement.  Think it through:  anchor size, chain not too big, chain length [longer to make shallow anchoring all chain OR 50 feet and nylon or new 8 strand???], and things like that.

Your selection of the 25 KG Rocna makes sense for a "maximum" storm anchor, and given Steve's design, appears to be overkill for your intentions and should be reconsidered.  Size the anchor for your cruising needs on a daily "I'm-gonna-use-THIS-anchor-ALL-THE-TIME" and save something else for your 100-year event.  Re-read Steve's discussion.  Mine's half his size, I'm designed for my use as defined above, his is twice the size of mine because he designed his anchoring system for something different than ours.

We want you to be happy raising it regularly, because we KNOW you'll just LOVE dropping it - don't let yourself get pulled off the bow - stand back!  :D

Once you buy into this concept, you'll find our toy bow rollers work just fine, like all the pictures on page 1 of this thread prove.

1/4 to 5/16 chain will be ALL you'll ever need - 3/8 is way overdoing it --- for me.  Check your calculations for your own system.

"Store" it on the bow, where it belongs.   :D :D :D


PS to Steve:  Happy Birthday to Tracy.  Yup, she's right here with us!
Thanks, Stu
« Last Edit: November 24, 2010, 08:21:19 PM by Stu Jackson »
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Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

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waterdog

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Re: Roll bar anchors on bow roller
« Reply #31 on: April 17, 2009, 08:49:24 PM »

I wouldn't suggest that anybody read too much into my anchor system design decisions.   Rocna doesn't recommend the 20 kg anchor for our boats.   They told me the 15 kg would be overkill.   My decision was based on excess.   I really don't want to be lying in bed at night wondering if the anchor manufacturer had the particular conditions in mind that I'm experiencing.  I want to sleep.   And at times on a long voyage, enough sleep will be a safety factor.    This is not an engineered solution.  It's an emotional one.   


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Steve Dolling
Former 1988 #804, BlackDragon - Vancouver BC
Now 1999 Manta 40 cat

Stu Jackson

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Re: Roll bar anchors on bow roller
« Reply #32 on: April 17, 2009, 09:13:18 PM »

Rocna doesn't recommend the 20 kg anchor for our boats.   They told me the 15 kg would be overkill.   My decision was based on excess.  ...  I want to sleep.   And at times on a long voyage, enough sleep will be a safety factor.    This is not an engineered solution.  It's an emotional one.  

That's a great DESIGN CRITERIA all in itself, and a very well engineered one.  

Sleep, gently sleep... :sleepy:

So, Braxton, given that, please reconsider your 25 KG selection.
« Last Edit: November 24, 2010, 08:23:05 PM by Stu Jackson »
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Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

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waterdog

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Re: Roll bar anchors on bow roller
« Reply #33 on: April 18, 2009, 12:24:37 AM »

For those with data driven view...   

Rocna bases their sizing chart on 50 knot wind and marginal silt type holding.   For our boats, they recommend a 15 kg for 50 knots stuck in baby poo.   A 10 kg would probably be fine for just about anything most of us regularly encounter.   My 20 kg anchor they would recommend for a 39 foot boat weighing 10 metric tonnes (or a 30 foot boat weighing 16 tonnes - I'd like to know if those actually float).   

However, in spite of their well articulated and conservative sizing philosophy, I still went bigger.   A sizing chart is just a chart.   It doesn't howl in your rigging.     
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Steve Dolling
Former 1988 #804, BlackDragon - Vancouver BC
Now 1999 Manta 40 cat

Braxton

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Re: Roll bar anchors on bow roller
« Reply #34 on: April 18, 2009, 03:17:50 PM »

I guess I'm miss reading the chart.   Looking at the chart it seems like their recommendations for us range from the 10 all the way up to the 25.   Am I reading this wrong?

BTW:  for those of you who want to follow along here is a link to the chart:
http://www.rocna.com/main.php?section=best&chapter=sizing&page=1
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Braxton Allport
1988 #805, Ballou - Tacoma WA

Stu Jackson

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Re: Roll bar anchors on bow roller
« Reply #35 on: April 18, 2009, 04:21:31 PM »

Braxton, thanks for the link, but ya gotta go deeper than just the chart.  Try this:  http://www.rocna.com/kb/Rocna_sizing_recommendations.  It's from a "continuation link" right below the basic main website chart.

It, in part, says:

Over-sizing

Many Rocna customers, in improving their anchor type by switching to a Rocna from an older anchor which they have learned to be unreliable, make doubly sure about their upgrade by also increasing the weight of their anchor. We see this tendency a lot, and try to discourage it. As above, our official sizing is very conservative, and in many cases it's a case of "don't over-size – we already did that for you!"

On a weight-for-weight basis, the Rocna represents a very significant step up from most other types, and doubling the size (for example) could inadvertently cause serious problems with retrieval and other handling issues.
[/color]

I added the bold.  I really think we've discussed all the options you DO have in terms of sizing.  If YOU choose to get a Rocna 25, I personally believe it's overkill, and was so noted before.  But, it's your boat and your back (windlass?) [requested again - don't know if you hand-haul or crank your anchor up].

I continue to recommend that you consult, for instance, Calder's Cruising Handbook, page 394,which has a very good anchoring SYSTEM sizing section that we used to select our anchor size and also to size each and every one of our components.

I am just trying, as far as I can, to help you avoid overkill and ending up a potentially very unhappy skipper.  Perhaps I am missing something, and maybe you could be thinking of using the new Rocna as your "storm" anchor, and I suggest that is incorrect based on your new $ investment, because what you really want to do is select the right size Rocna for your daily use, which I discussed in detail earlier.  I did re-read your Reply #27, BTW.  If all you want is a "storm" anchor, and you choose the Rocna for it, by all means get the heaviest, meanest, most impossible to retrieve piece of hardware you possibly can.  But then, what are you planning to use as your "regular" anchor?  One of those old things you already have?  Which is the reason in the first place for you to even consider a Rocna (or any other new-style new generation anchor); it's the old ones that won't let ya sleep!

And I sincerely don't believe for a moment that you'd use one of your old anchors during the day and then haul out your new "storm" anchor if you decide to stay overnight at an anchorage.  Buy the right sized Rocna, and simply use it.  What could be easier, on you and your wallet?

Ron Hill has explained anchoring techniques many, many, many times here, and I don't wanna have to have him retype it all again (he's our "hunt-and-peck" typist):  Your daily anchor should be used, and it should hold your boat and sized for your anticipated conditions.  Lunch hooks are useless and dangerous.  The hook should hold and be appropriately sized for retrieval as well as holding power.

PS:::  BTW, Craig Smith of Rocna asked me to contribute photos of our setup with our new Rocna awhile ago.  I sent him a few, and today I suggested he come over and check out this thread with its many photos.  He may ask some of you for them in better res.

PPS:::  And, Braxton, many times Ron Hill has reminded us that if we have questions sometimes it's best to go to the horse's mouth, the manufacturer, and not simply rely on our opinions here, 'cuz we're just so opinionated, right?   8)  So, Braxton, why not get in touch with Craig directly?  Here ya go:  craig at rocna dot co dot nz  Ask him, please, and you may want to refer him to this thread and see what he has to say.  I'd love to know.
« Last Edit: April 18, 2009, 09:54:31 PM by Stu Jackson »
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Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

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waterdog

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Re: Roll bar anchors on bow roller
« Reply #36 on: April 18, 2009, 04:30:11 PM »

I guess I'm miss reading the chart.   Looking at the chart it seems like their recommendations for us range from the 10 all the way up to the 25.   Am I reading this wrong?

BTW:  for those of you who want to follow along here is a link to the chart:
http://www.rocna.com/main.php?section=best&chapter=sizing&page=1

I think a little bit.   You start out with a length.   Seems like you're reading off the 33 foot row.   I read the rating off the 36 foot row, because we're closer to a 36 footer than a 33.   If you read along the 36 foot row, you would throw out the 10 because our boats are more than 3t. (unless you aren't looking for 50kts)    At 7t the 15 would be fine.   And I think you stop there with the 15 as your preferred size.   The 20 and 25 and 33 are recommended for 36 footers with severe dietary problems.   

 
« Last Edit: April 18, 2009, 04:31:00 PM by waterdog »
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Steve Dolling
Former 1988 #804, BlackDragon - Vancouver BC
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Stu Jackson

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Re: Roll bar anchors on bow roller
« Reply #37 on: April 18, 2009, 04:36:37 PM »

... footers with severe dietary problems.   

Oh, shoot, you've defined a "cruiser!"
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Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

"There is no problem so great that it can't be solved."

Stu Jackson

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Re: Roll bar anchors on bow roller
« Reply #38 on: April 20, 2009, 10:09:12 AM »

Thanks to Craig Smith of Rocna

Braxton, as previously reported, Craig's been in contact with me.  I sent him my high res photos, and he reported back to me as follows:

Hi Stu,

Thanks for those photos. I haven’t heard back from anyone else yet, but you can see your pics on the C34 page here:

http://www.rocna.com/kb/Catalina_34

I’ve also placed some abridged comments relating to fit compatibility plucked from your posts, feel free to tell me to edit if you wish.

I’m sure any of prospective Rocna owners with C34s will appreciate that resource.

This is an entry in our “knowledge base”, which you may like to explore further – one of the bigger sections is this collection of “boat cases”, which I hope will grow to a comprehensive size over time:

http://www.rocna.com/kb/Category:Rocna_bow_compatibility

Note also the links to articles on “bow roller assembly design” (for custom ‘from scratch’ bow rollers) and “common fit challenges” (as pertain to the Rocna).

Regarding your thread, actually I believe that you and Waterdog are doing a fairly good job, I don’t have much to add. The official Rocna sizing recommendation for the C34 is a Rocna 15, as the closest row on our sizing chart is 36’ and going out along the displacement ranges, the C34’s 5.4 tonne weight (plus a bit loaded) selects the 15 column. If we look at the Rocna 10, the closest we can get to the C34 specs is 33’ at 4 t, so we can be sure that the 15 is the correct choice. However, the C34 is not too far away from this point, so it is safe to say that the 10 would be adequate for most conditions, just not quite the conservative criteria we use (you are familiar with our philosophy on this). Similarly the 15 goes a bit in the opposite direction, making it even more conservative.

I hope that is of interest.

Best regards,

Craig Smith


For those of you with photos, please help Craig by sending him your pics and he will post them on the Rocna 'site.

For summary, again, we bought a Rocna 10 (22#), Steve has a 20 (do the math! :D).

I don't have anything professionally or personally to do with Rocna.  I just did my research and homework and sized our system and bought the Rocna 10 (also thanx to the C36 local fleet discount back then - very good promotional idea from the C36 fleet and Rocna).  I had two choices back then, pretty obvious, huh, as far as manufacturers were concerned - there really only still are two choices for the new V3.0 anchors these days.

Given this assistance direct from the manufacturer, and the way they fit on our toy bow rollers, I can report that we are very happy with our choice of both size and vendor.
« Last Edit: March 14, 2016, 04:30:08 PM by Stu Jackson »
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Stu Jackson, C34 IA Secretary, #224 1986, "Aquavite"  Cowichan Bay, BC  Maple Bay Marina  SR/FK, M25, Rocna 10 (22#) (NZ model)

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Michael Shaner

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Re: Roll bar anchors on bow roller
« Reply #39 on: April 21, 2009, 06:23:23 AM »

"Re: Roll bar anchors on bow roller" happened to be the last project before splash this weekend. We opted for the 35# Manson and the long roller from CD. After several weeks of fear and trepidation, I finally put on my "big girl panties", picked up the grinder and started cutting stainless. Whittling on my boat gets me a little bunged up. All in all, I think it came out OK. Can't wait to get the hook dirty this weekend...hope I can get it back up!

The challenging part for me in piecing together the anchor "system" was the connection between the 1/4" HT chain to an anchor with a  3/8" shank and getting any kind of respectable working load out of it. Oh, yeah...and 8 plait to chain splice... (only took me 2 hours)  :shock:
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