Rocna 10 or 15?

[NorWyn]

We have a 10kg Bruce type anchor on our Camano with 150 feet chain and 150’ 3 stand nylon.

I am guessing our chain well outweighs the extra 5kg you are looking at for the new anchor if you only have 50 feet of chain.

We are very satisfied with this set up, anchoring out more than half the time. No issues with the bow being heavy. The flybridge still drains off the stern adequately when moored in a rain storm so I don’t think we are overly “bow heavy”. The bow actually rides higher than I like when we cruise over 8 knots (no trim tabs).

-Chris

 

[Nomad Willy]

NorWyn,
Got any idea what (if anything) the manufacturer says about trim? Manual?

 

[Peter B]

Anyone using a Rocna anchor? Looking at the 10kg or 15kg. Sizing chart puts me right on the line for the 10kg but not super excited about the extra weight of the 15kg on the bow.

Jamey

I was completely happy with a Super-Sarca on my GHB34 of 22kg. If you have a good windlass, like others, I'd say go with the 15kg and sleep better.

 

[bogranjac1]

Anyone using a Rocna anchor? Looking at the 10kg or 15kg. Sizing chart puts me right on the line for the 10kg but not super excited about the extra weight of the 15kg on the bow.

Jamey

I followed the Rocna sizing chart and purchased a 7kg anchor as recommended.
I employ 10 meters of chain ( a little or boat length ) then 3 strand rope.
I ALWAYS have a scope of 3-1 or better
I have NEVER failed to set the anchor first time and have NEVER dragged anchor in any seabed conditions
Follow Rocna guidelines and rest easy

 

[NorWyn]

NorWyn,
Got any idea what (if anything) the manufacturer says about trim? Manual?

The manual speaks more to trimming for list by balancing loads and fuel/water tanks, as opposed to for how the bow rides. I am aware that some Camanos do have trim tabs which I suspect would ameliorate the bow riding as high as mine does at higher speeds.

Perhaps Camano owners with trim tabs can chime in respecting their experiences.

-Chris

 

[Pau Hana]

Anyone using a Rocna anchor? Looking at the 10kg or 15kg. Sizing chart puts me right on the line for the 10kg but not super excited about the extra weight of the 15kg on the bow.

Jamey

Greetings, Jamey,

With all due respect, you asked a question and have received some excellent real world advice. My dos centavos-

Your focus is misplaced. Always focus on safety- you never know when the ground tackle will be needed. A boat can be ballasted to balance any weight concerns on the bow- just as it can be ballasted side to side.

I recommend the 15 (at a minimum) plus adding chain.

 

[Nomad Willy]

Yes the list problem .........
Usta address that at Uniflite. Moving batts ect around to balance the roll axis.

Having been in the business I know every boat is different. So few boats will be perfect. But a bow high condition is the way of things on planing and SD. I would think the faster you go the further aft one’s CG should be .. small deviations I’m talking. But if you trim for speed (say 10-12knots) the CG may be too far aft when you slow down to 8 knots. So the hull is designed for one speed (or a range of speeds) and the CG is ideal for one speed. Hopefully the same speed. But if you’re dialed in to 8 knots and need to slow to 6 knots because of following seas the bow may try to steer the boat on the face of waves unless the CG is far enough aft. And if you want the 8 knot boat to go faster (and you have the power) you may not be able to climb the wave as your bow will be really really high. You can see where trim tabs may be good for such a boat. And the Camano may be such a boat. I know the Camano is Capable of 20 knots. But if trim tabs are used large ones would be more effective. I’m generally against tabs .. just an opinion.
All boats are different and I always trim mine a bit stern heavy for better directional stability w stern seas.

My point of all this is just that trim, speed and CG are very important.

 

[ranger58sb]

How does a 31' Camano compare to on early 34 Mk III Mainship? IIRC our mainship was about 14,000 lbs (?) with a 12' beam...

Anyway, if it helps, we tried a 35-lb Delta with 50' of chain and it wasn't sufficient to hold the boat securely in Chesapeake slime in all weather conditions. Wasn't horrible, and we learned to manage our anchoring (mostly not) in those "conditions" -- but at least that would have lead me to believe a larger Rocna would be better than a smaller one. (Although IIRC the Rocna didn't test all that well in the Fortress mud tests of a few years ago anyway.)

-Chris

 

[NorWyn]

Camano Troll is 31’ (loa) with 10.5’ beam and 10,000lbs dry....so the Mainship 34 is about 1.5 times the size.

20knots for our Camano, at least, would be optimistic. Perhaps 18 at WOT with helping current. I agree with your comments on trim tabs, Willy but can’t justify them for our usual ten knot maximum cruising speed (more often we are between 6 and eight knots).

Back to the OP thread...again, we have yet to drag with a 10kg Bruce type so don’t see a need to change. I think that is what the manufacturer provided. Rocna sure seems popular though judging from the posts here and elsewhere.

 

[psneeld]

Heck...most boaters here..... between a couple of cruisers aboard..... I bet the couple gains and loses more than 10 pounds every year....


I know 10 pounds midships is different...but.....


If you add 10 pounds on the bowsprit and 20 pounds aft to counteract...the boat's total displacement goes up 30 pounds, about 1/2 cubic foot of water. A typical 29 foot boat with an 8 foot beam might have more than 120 square feet of surface area at the waterline....but lets use 120 sq ft.



With that calculation assumed, I believe based on my rushed calculations, that boat would only sink 0.05 inch.....but I would love a better mathematician correct this if in error....or a better NA that ventures how much aft ballast is needed to offset 10 pounds.

 

[Nomad Willy]

NorWyn,
I have a 22lb no name Claw and it always performed well. I would consider it not quite up to par w your windage though. The Willard weighs two tons more than the Planing Camano. I’d get a Excel the same weight at least if I were you. But there’s many many people out there w Claws that are as happy as you w them.

You wrote;
“ 20knots for our Camano, at least, would be optimistic. ”
That may be an indication that your boat may have a few add-ons and is heavier than when new. Sounds like your’e dialed in to a good place w your speed. With our weight, power and hull-form we just keep slugg’in along at 6 knots.

 

[NorWyn]

On reflection, you may be onto something, Willy.

We do carry the dingy and six horse outboard on the swim platform and that likely accounts for the lower top speed, as well as some portion of the high riding bow at higher speeds.

If not in a hurry or on a longer run, six knots is just fine by us.

Cheers,

Chris

 

[rslifkin]

On a hull that can plane, I'd personally rather have it shove the bow in the air and need to add stern lift with trim tabs than the other way around. First, given big enough trim tabs to get significant lift without them down far enough to add a lot of drag, it may get more hull out of the water and have less total drag. And as Willy would point out, being able to keep the bow up enough is important in a following sea, especially at higher speeds.

For an example of trim tab usage, I've got massive 48x12 tabs on my boat (which is rather stern heavy, especially with full fuel tanks). Fully retracted, the trailing edge of the tabs are a bit over 1/2" above flush with the hull, so they basically do nothing. Run like that and the boat struggles onto plane, runs very bow high above hull speed, etc. Drop the tabs down to where the trailing edges are about 1/2" below the hull (so they extend the running surface by a foot and add a slight downward deflection) and the boat climbs right up onto plane, goes significantly faster for a given engine power setting and runs at a much nicer angle.

Most of the times where trim tabs don't work well are when they're just too small and end up being deflected very far down, which adds a lot of drag relative to the lift they provide.

Of course, if you rarely or never run much above hull speed, it's probably not worth adding them.

 

[Nomad Willy]

rslifkin,
It sounds like you brought lots of experience into that last post. Thanks

 

[AKDoug]

Before trim tabs, you just moved weight forward in the boat if you planed. I ran a stern heavy Bayliner for years, and made a point of moving everything I could forward so it planed out more quickly. Loading the stern and then counting on your trim tabs to level it out probably isn't your most efficient plan.

I mostly used my trim tabs to level the boat, not hold the bow down. But that's just me...

 

[rslifkin]

Before trim tabs, you just moved weight forward in the boat if you planed. I ran a stern heavy Bayliner for years, and made a point of moving everything I could forward so it planed out more quickly. Loading the stern and then counting on your trim tabs to level it out probably isn't your most efficient plan.

I mostly used my trim tabs to level the boat, not hold the bow down. But that's just me...

It depends on the boat. With my hull, if you move people forward and then re-trim to get best speed, the boat runs slower than it does with the weight further aft. To me, that indicates that with the weight aft and tabs further down, I'm getting enough extra lift to produce a reduction in hull drag that outweighs the increase in tab drag.

 

[backinblue]

Can anyone comment as to the extra 11 pounds of weight as it relates to the windlass' ability to operate it? Worried about the extra straight due to additional weight. Not seeing any reference in the manual. Maxwell Freedom 800.

The 11lbs added to the windless load is negligible. Also, that small amount of weight added at the bow is also insignificant. Go with the bigger anchor and forget about it and sleep well at night knowing you'll be well-hooked in all but the most extreme conditions. If you are still that concerned about anchor weight, there are lighter anchors with greater holding power, but that's not what I would consider the most important factor when selecting a new anchor.

 

[foreverunderway]

Putting together your anchor and rode isn't just about the weight of the anchor, but also about the chain and/or line you are using. Properly sized anchor tackle is a complete system.
I know folks who use a 125# anchor on 3/8" BBB chain. I know others who use the anchor from the manufacturer's chart, but have oversized chain. Neither is preferable. When one has an extra heavy anchor and the chain's too light, the catenary curve isn't working as it should and the chain can become tight between the bow and the anchor and then it will fail. No vessel can carry chain strong enough to hold the boat w/o the catenary curve and a snub line. But, in extreme circumstances, things don't always go as planned and the snub can break, then the chain.

On the other side of the coin, when the chain is too heavy, the anchor may not set at all and the boat will rest on the chain until circumstances change and the chain stretches out and one is not anchored where one wanted to be.

Five kilos is not a big difference out of the water, but IMO, if you are using the proper size chain, it is a big difference in the water, so I'd go for the heavier of the two. Just for info, we use ½" BBB chain with a 44 kilo Rocna on a 77,000# boat with a 1" nylon snub line 25 feet long. We sleep well at night.

 

[Scottwb96]

Best advice I ever got on an anchor... "as long as your equipment can handle it, nobody ever complained they had too much anchor!"

 

[Harry47]

Its 11-12 pounds. Just put a couple of gallons of water on the bow and see what happens. In the dark of night, with the wind blowing I don’t think that you will be saying the smaller anchor would be better.

 

[NCheaven]

2005 Camano — North Carolina. I replaced a 10 kg claw/150’ chain, 100’ 3 strand with a 15 kg Rocna, 50’ chain, 150’ 3 strand. Shallow southern waters and sometimes soft mud needed more fluke surface area vs longer chain and longer total rode (was a New England boat), in my opinion. New tackle is lighter, but that is not a factor I considered. Happy with the change. Danforth lunch hook. If I ever plan to go north of the Chesapeake again, I’ll put the 150’ chain on the Rocna.

 

[YukonRon]

We have a Ranger Tugs R25 and upgraded to the Rocna 15. We use 50' of chain and 250' of 8-plait nylon rode. We love the anchor and are very happy with the way it sets and holds, and don't think it looks overly large on our small(er)boat. I did move some tools out from under the v-berth to a location further back, but I really didn't notice any difference with the weight either way.

 

[Nickair]

Anyone using a Rocna anchor? Looking at the 10kg or 15kg. Sizing chart puts me right on the line for the 10kg but not super excited about the extra weight of the 15kg on the bow.

Jamey

Would always go one size larger. Always.
You can move other things from the for end to the stern to overall ballast the extra weight of the anchor.

 

[kendad]

I'm in a 350 Mainship with the 15 and I've put it to the test several times with success, go big!

 

[Parro]

I am packing a 15K on the bow, have a spare 10K on board as a backup. I am in the same size boat as you are, and I would go with a 15K if I were you. I pulled it by hand for a couple of years, once the windlass went on I went from 15' of 5/16" chain to 50'.

The 10K has never been wet. If I lost the 15K, I would go up one size in replacing it. JMO

PS... throw some weight in the stern if you are worried about being bow low. That's what I did, but then again I am full displacement.

Probably not relevant but I have a 80kg (170lb?) Bruce and another heavier anchor.
I use the Bruce for the muddy bottom we have but most nights I wish it was bigger.

 

[Jim W.]

I’ve been using the 15kg on a 29’ performance cruiser for 6 years . 100’ 1/4” chain 200’ 3 strand twist on a Lewmar profish 700 windlass . I anchor out most of the summer in New England no matter how hard it blows you always feel secure . You have much more windage on the Camano I wouldn’t feel secure with anything less than the 15kg . They seem to shrink between the store and the bow.

 

[Nomad Willy]

I’ve done two 50 knot gales. One w an 18lb anchor and the other w a 13lb anchor w/o a lot of chain.
No dragging. Perfect performance.
Why should I go a size up?
Rocna sizes for 50 knots. What aize did they recommend?
I’d recommend a R-15 .. what 22lbs?
The way people rave about the Rocna a 10lb should do.

 

[rslifkin]

I’ve done two 50 knot gales. One w an 18lb anchor and the other w a 13lb anchor w/o a lot of chain.
No dragging. Perfect performance.
Why should I go a size up?
Rocna sizes for 50 knots. What aize did they recommend?
I’d recommend a R-15 .. what 22lbs?
The way people rave about the Rocna a 10lb should do.

Based on the Rocna chart, it looks like the 10kg / 22lb is marginal, the 15kg / 33 lb would be solidly recommended. Looks like a Camano 31 is listed as 10,000 lbs (probably dry). Rocna says up to 11,020 lbs at 30 feet, 8820 lbs at 33 feet for the 10kg, so he'd be right on the upper edge or just over. For the 15kg, they say up to 15,430 lbs at 30 feet, 13,320 lbs at 33 feet. So the 15 is definitely big enough according to their chart.

Personally, I'd get the 15 in that situation. And maybe even think about the 20, although that's probably overkill.

In general, going up a size adds more margin for error. So it might be the difference between "can survive a 50 kt gale in good holding" and "can survive a 50 kt gale in mediocre holding". Your boat is particularly low windage, so you gain some margin from that and can therefore get away with less anchor than most on here would.

 

[Nomad Willy]

rslifkin,
Yes our low windage.
I’ve only recently given that thought much weight.
Speaking of weight Willy is not light at 8tons and 30’ but we have not anchored much in windy places. SE Alaska is usually calm at night in most protected anchorages. If many of those anchorages had been windy my record anchoring wouldn’t be so good.

But I still think going from an old low performance anchor one shouldn’t need “one size up” considering more holding power would probably be gained w the new age anchor that one size up. But if you had a new age anchor and were experiencing dragging and bought another new age anchor one size up would seem to be justified.

 

[Hamilton]

I installed the 15 kg. Rocna 4 years ago and have had no issues. Pulpit shows no issues with the weight and was thankful to have it when we were anchored out for a week and a strong squall blew through. Also didn’t notice any change really in the bow being weighed down after the install. No regrets going with the 15.