What Size Anchor Do I Need?
The Jimmy Green Anchor Size Comparison Chart is compiled from individual manufacturer recommendations and highlights how similar the suggestions are across various designs.
How to choose your Anchor Weight by Manufacturer
- Find the column below that best represents your Boat Length Overall.
- Compare your displacement with the tonnage listed.
- If the displacement is greater than displayed in your column in the table, or the yacht is a multihull, consider moving across to the next column to increase the diameter.
- Consider the worst-case scenario for your anticipated Anchoring - this will dictate whether you go for the minimum required or the ocean cruising approach
- Consider the manufacturer sizing parameters listed below the tables
- Compile a short list of potential anchors to consider
|6 - 8
|8 - 10
10 - 12
|12 - 14
|14 - 16
16 - 18
|18 - 20 metres
|Anchor Type||< 1 tonne||1 - 2.5 tonnes||1 - 2.5 tonnes||2.5 - 5 tonnes||2.5 - 5 tonnes||5 - 9
|5 - 9 tonnes||9 - 13 tonnes||9 - 13 tonnes||13 - 16 tonnes||13 - 16 tonnes||16 - 20 tonnes||16 - 20 tonnes||20 - 25 tonnes||20 - 25 tonnes||25 - 40 tonnes|
|Mantus and Mantus MK 2||5.9kg||5.9/7.7kg||7.7kg||11.4kg||15.9kg||15.9/20.5kg||20.5kg||25kg||25kg||29.5kg||29.5/38.6kg||38.6kg||38.6/47.7kg||47.7kg||56.8kg||70kg|
|Spade Galvanised and S/S||6kg||6/10kg||10kg||10/15kg||15kg||15/20kg||15/20kg||20kg||20kg||20/25kg||25kg||25kg||30kg||30/37kg||37/44kg||44/55kg|
6 - 8
8 - 10
|10 - 12
|12 - 14
|14 - 16
|16 - 18
|18 - 20
|Anchor Type||< 1 tonne||1 - 2.5 tonnes||1 - 2.5 tonnes||2.5 - 5 tonnes||2.5 - 5 tonnes||5 - 9 tonnes||5 - 9 tonnes||9 - 13 tonnes||9 - 13 tonnes||13 - 16 tonnes||13 - 16 tonne||16 - 20 tonnes||16 - 20 tonnes||20 - 25 tonnes||20 - 25 tonnes||25 - 40 tonnes|
Rex Francis has set the Anchor Right parameters for the Sarca Excel in a slightly different format. However, it can still be compared with other anchor designs with a little interpretation.
SARCA Excel Parameters - Length and Displacement
Anchor Right Advisory - If your boat is over the limit in either column, it is advisable to upgrade to the next size.
Upgrading one size for a multihull or long-term anchor dependent cruising would also be considered good practice.
|Yacht Length Overall||< 5 metres LOA||5 - 7 metres LOA||7 - 10 metres LOA||10 - 12 metres LOA||12 - 15 metres LOA||15 - 17 metres LOA||17 - 19 metres LOA||19 - 21 metres LOA||21 - 23 metres LOA||23 - 25 metres LOA||25 - 27 metres LOA|
|Weight||< 1.2 tonnes||1.2 - 2.8 tonnes||2.8 - 3.5 tonnes||3.5 - 7 tonnes||7 - 15 tonnes||15 - 21 tonnes||21 - 24 tonnes||24 - 28 tonnes||28 - 32 tonnes||32 - 36 tonnes||36 - 42 tonnes|
|Sarca Excel Weight||7.5kg||9.5kg||12.5kg||16kg||22kg||30kg||36kg||40kg||50kg||55kg||63kg|
|Sarca Excel Size||#1||#2||#3||#4||#5||#6||#7||#8||#9||#11||#13|
Most anchor manufacturers publish a recommended weight of anchor by either the length overall or a combination of length, displacement and windage.
Some top manufacturers also include weather conditions and distinguish between monohulls and multihulls.
The top manufacturers are generally conservative and specify more criteria to help you choose.
The authority of each manufacturer recommendation may be judged by several factors: reputation, personal experience, research, the number of relevant factors taken into account, and the amount of detailed information they publish on the subject.
The Jimmy Green Anchor Size Chart collates the recommended sizing for all the anchors we offer on our website and highlights how similar the recommendations are.
Interpretation is still required, e.g. multihulls, high windage profile and extreme weather.
Anchor Sizing Parameters by Manufacturer
A more detailed explanation of how the data for individual anchors is presented and how it is collated into the Comparison Table follows:
Galvanised and Stainless Steel Anchors
Rocna and Vulcan, Galvanised and Stainless Steel - Length and Displacement
Rocna/Vulcan recommend an anchor one size larger than indicated in their guide for multihulls
Quote from their Fitment Guide - ”our anchor sizing recommendations are intended to provide an anchor adequate for use in most all conditions. We base our calculations on 50 knots of wind, associated surge, and poor holding bottoms.”
Mantus Mark 1 and 2 – Length, Displacement and Wind Speed
Mantus Quote - “we are generally referring to the needs of a cruising boat spending most of its time on anchor. In doing so, we try to envelope high sustained winds (50 knots) and assume poor holding conditions (low viscosity bottoms).”
Mantus publish a chart in three categories – “Lunch Anchor category is recommended for lighter use, expected winds under 30 knots, working anchor for winds under 50 knots and finally, storm anchor recommendations are intended for winds above 50 knots.”
N.B. The Jimmy Green Comparison Table is derived from the Mantus middle category.
Spade Galvanised and Stainless Steel – Length and Displacement
Spade recommend an anchor one size larger than indicated in their guide for multihulls
UltraMarine Stainless Steel – The UltraMarine Anchor Size Guide considers multiple factors. Their comprehensive approach includes Length, Displacement, Mono/Multihull and Windage Profile criteria.
Lewmar Epsilon, Delta and Claw – Length only
Lewmar guidelines are illustrated in a shaded colour range by length only, so you need to judge displacement, i.e. light, average, or heavy, compared with similar length yachts. If the answer is heavy, upgrading to the next size is advisable.
Plastimo Britany – Length only
Plastimo Quote – “Anchor weight per boat length is only given as an indication. However, your anchor selection should also recognise the specific construction of your vessel.”
Using a lightweight anchor goes against the traditional belief that weight is one of the most critical factors in holding power.
Fortress Quote – “Fortress design does not depend upon weight to provide world class performance.”
However, the most popular application for aluminium anchors is as a convenient, high holding power secondary or kedge anchor.
Fortress/Guardian – Length only
Fortress Quote – “Boat anchor size recommendations are for boats of average windage and proportions in 30 knots of wind, average bottom conditions, and moderate protection from open seas. Remember that the loads in 42 knots of wind are twice as much as in 30 knots.”
Spade Aluminium – Length and Displacement
Spade recommend an anchor one size larger than indicated in their guide for multihulls.
Spade Quote – “Aluminium version not recommended for use as a primary anchor.”
Lewmar LFX – Length only
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