Sizing Guide

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To choose the correctly sized Rocna, match your vessel's length with the most appropriate displacement range, also bearing in mind conditions of intended use (if in doubt, give preference to the larger anchor model).

For multi-hulls: use the chart as instructed, then select the model one size larger

Please note: Our sizing guide is now available in three units of measurement for your convenience: Metric Tonnes, Short Tons (used primarily in North America) and Pounds.

 

Metric Tonnes (click to zoom)

Short Tons (click to zoom)

Pounds (click to zoom)

 

* Weights and areas may vary slightly
Vessel displacement units: 1 t (metric tonne) = 1,000 kg = 2,205 lb

 

Instructions:

To choose the correctly sized Rocna, match your vessel’s length (down the column on the left) with the most appropriate displacement range (go out along the appropriate row), also bearing in mind conditions of intended use (if in doubt, give preference to the larger anchor model).

 

For multi-hulls: use the chart as instructed, then select the model one size larger

 

Our sizing is conservative

Unlike other manufacturers, our sizing recommendations are intended to provide an anchor adequate for use in most all conditions. We base our calculations on 50 knots wind, associated surge, and poor holding bottoms. For more on our philosophy and rationale, please consult our knowledge base article:

http://kb.rocna.com/kb/Rocna_sizing_recommendations

 

The Rocna 150 (331 lb) and larger

We do not provide standard recommendations for boats larger than those for which the 110 would be the recommended size. This is because of increasing complexities of the factors involved. Furthermore, classification society rules and/or legal requirements are likely to dictate the anchor sizes mandated for these vessels.

 

Classification Rules sizing

Rocna anchors from sized 110 kg (243 lb) and above may be sized based on classification society Rules for SHHP anchors. Such Rules permit a mass 33% lighter than HHP types, or 50% less than "standard stockless" types. Anchor sizing is based on a vessel's separately calculated Equipment Number (EN). For more information, please consult the Rocna Knowledge Base articles on Rocna sizing recommendations and classification