What Size Anchor Do I Need?
The Jimmy Green Anchor Size Comparison Chart is compiled from individual manufacturer recommendation.
| < 6 metres LOA | 6 - 8 metres LOA | 8 - 10 metres LOA | 10 - 12 metres LOA | 12 - 14 metres LOA | 14 - 16 metres LOA | 16 - 18 metres LOA | 18 - 20 metres LOA | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 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 tonnes | 16 - 20 tonnes | 16 - 20 tonnes | 20 - 25 tonnes | 20 - 25 tonnes | 25 - 40 tonnes | |
| Galvanised and Stainless Steel | Rocna | 4kg | 6kg | 6/10kg | 10kg | 10kg | 15kg | 15/20kg | 20/25kg | 25kg | 25/33kg | 33kg | 33kg | 40kg | 40kg | 55kg | 55kg |
| Vulcan | 9kg | 9kg | 9/12kg | 15kg | 15/20kg | 20/25kg | 25kg | 25/33kg | 33kg | 33kg | 40kg | 40kg | 55kg | 55kg | |||
| 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 | |
| UltraMarine Ultra |
5kg | 5/8kg | 8kg | 8/12kg | 12kg | 12/16kg | 16kg | 21kg | 21kg | 27kg | 27/35kg | 35kg | 35/45kg | 45kg | 45/60kg | 60kg | |
| Lewmar Epsilon | 4kg | 4kg | 6kg | 6kg | 10kg | 10kg | 16kg | 16kg | 20kg | 20kg | 25kg | 25kg | 32kg | 32kg | 40kg | 40kg/50kg | |
| Lewmar Delta | 4kg | 6kg | 6/10kg | 10kg | 10kg | 10/16kg | 16kg | 16/20kg | 20kg | 25kg | 32kg | 32kg | 40kg | 40kg | 50kg | 50/63kg | |
| Lewmar Claw | 5kg | 5kg | 5/7.5kg | 7.5kg | 10kg | 10/15kg | 20kg | 20kg | 30kg | 30kg | |||||||
| Plastimo Britany | 6kg | 6/8kg | 8kg | 10kg | 12kg | 14kg | 16kg | 16/20kg | 20kg | 20kg | |||||||
| < 6 metres LOA | 6 - 8 metres LOA | 8 - 10 metres LOA | 10 - 12 metres LOA | 12 - 14 metres LOA | 14 - 16 metres LOA | 16 - 18 metres LOA | 18 - 20 metres LOA | ||||||||||
| 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 tonnes | 16 - 20 tonnes | 16 - 20 tonnes | 20 - 25 tonnes | 20 - 25 tonnes | 25 - 40 tonnes | |
| Aluminium | Fortress | FX7 | FX7 | FX7/FX11 | FX7/FX11 | FX11 | FX11 | FX16 | FX16 | FX23 | FX23 | FX37 | FX37 | FX55 | FX55 | FX85 | FX85 |
| Guardian | G7 | G7 | G11 | G11 | G16 | G16 | G23 | G23 | G37 | G37 | |||||||
| Spade Aluminium | A40 | A40 | A60 | A60 | A80 | A80 | A100 | A100 | A140 | A140 | A140 | A140 | A140 | A140 | A200 | A200 | |
| Lewmar LFX | LFX4 | LFX4 | LFX4 | LFX4 | LFX7 | LFX7 | LFX10 | LFX10 | LFX15 | LFX15 | LFX21 | LFX21 | |||||
Rex Francis has set the Anchor Right parameters for the Sarca Excel in a slightly different format which is best analysed by interpreting the information for comparison with the other anchor designs.
SARCA Excel Parameters - Length and Displacement
Anchor Right - If your boat is over the limit in either column, it is advisable to upgrade to the next size.
Upgrading one size either for a multihull, or for 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/or distinguish between monohulls and multihulls.
The top manufacturers are generally conservative and specify more criteria to help you make your selection.
The authority of each individual manufacturer recommendation may be judged by several factors: reputation, personal experience, research, the number of relevant factors that are taken into account, and the amount of detailed information that they publish on the subject.
The Jimmy Green Anchor Size Chart collates the recommended sizing for all the anchors that we offer on our website and highlights how similar the recommendations are.
Interpretation is still required for e.g. multihulls, high windage profile and extreme weather
Anchor Sizing Parameters by Manufacturer
Below we explain in more detail how the data for each individual anchor is presented and how it is collated into the Comparison Table above.
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 takes multiple factors into consideration, Their comprehensive approach includes criteria on Length, Displacement, Mono/Multihull and Windage Profile.
Lewmar Epsilon, Delta and Claw – Length only
Lewmar guidelines are illustrated in a colour shaded range by length only, so you need to make a judgement regarding displacement i.e. light, average, or heavy compared with similar length yachts. If the answer is heavy, it is advisable to upgrade to the next size.
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”
Aluminium Anchors
The concept of using a lightweight anchor goes against the traditional belief that weight is one of the most important 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 primary anchor”
Lewmar LFX – Length only