15th Aug 2024
The wetted surface area calculator will apply to most motor cruisers and sailing boats.
Calculate the area and select the water type from the tables to obtain the required number of hull anodes.
Measurements required:
Water line length = LWL
Beam = B
Draft = D
LWL x (B + D) = wetted surface area in meters squared
As an example, the table below shows the number and type of anodes required for 2 years per water type for a steel hulled boat. Ideally, you should check the voltage readings for your vessel to ensure it’s in the range recommended for the hull type.
| Area (meter squared) | Fixing Type | Salt | Salt | Salt/Brackish Water | Salt/Brackish Water | Fresh Water | Fresh Water |
| Hull | Rudder | Hull | Rudder | Hull | Rudder | ||
| Up to 28 | Stud/Bolt | 4 x 00271E | 2 x 00105UK | 4 x 00271EAL | 2 x 00105UKAL | 4 x 00271EMG | 2 x 00102UKMG |
| Up to 28 | Weld | 4 x 00306 | 2 x 00351 | 4 x 00306AL | 2 x 00351AL | ||
| 28.1 - 56 | Stud/Bolt | 8 x 00271E | 2 x 00105UK | 8 x 00271EAL | 2 x 00105ukal | 4 x 00309 | 2 x 00102UKMG |
| 28.1 - 56 | Weld | 4 x 00306 | 2 x 00351 | 4 x 00306AL | 2 x 00351AL | ||
| 56.1 - 84 | Stud/Bolt | 4 x 00271E | 2 x 00105UK | 4 x 00272EAL | 2 x 00102UKAL | 6 x 00310MG | 2 x 00351/2/BMG |
| 56.1 - 84 | Weld | 6 x 00309 | 2 x 00351 | 4 x 00309AL | 2 x 00351AL | ||
| 84.1 - 102 | Stud/Bolt | 2 x 000271E | 2 x 00105UK | 8 x 00271EAL | 2 x 00102UKAL | ||
| 84.1 - 102 | Weld | 6 x 00309 | 2 x 00306 | 6 x 00309AL | 2 x 00351AL | ||
| 102.1 - 148 | Stud/Bolt | 8 x 00271E | 2 x 00105UK | ||||
| 102.1 - 148 | Weld | 8 x 00309 | 2 x 00306 |
