LOW MAGNETIC PERMEABILITY EQUIPMENT FOR MCMV
Having had a long experience in the shipping industry for more than 80 years , Posidonia is also becoming well known for the special equipment that must be installed on mine countermeasure vessels (MCMV) such as minesweepers, minehunters or drones.
All the equipment has to be as light as possible and have low magnetic permeability, but keep a high performance.
Posidonia is a leader in welded anchors and chains, reducing the weight on board by offering:
- Super High Holding Power anchors (PTW+ ®)
- Chains in high tensile steel Grade 3
Both in low magnetic permeability steel: a unique combination fully approved by shipping classification registers.
Low magnetic permeability has not to be confused with magnetism.
It is the measure of the ability of a material to support the formation of a magnetic field within itself , typically represented by the (italicized) Greek letter µ (*).
The most common material that complies to the above is generally AISI 316L or 304L,
but it doesn’t exist in GRADE 3!.
After several years of R&D Posidonia identified new materials, with a special manufacturing process to achieve GRADE 3 chains keeping a very low magnetic permeability.
Several years ago the average magnetic permeability value was fixed at µ < 2,0, nowadays the average required value is approx. µ < 1,38.
We are now able to supply chains µ < 1,00 and anchors µ < 1,09
A medium/small MCMV with an average equipment number between 240-280 needs to be equipped with:
Option A (Grade 2 + HHP)
12 lengths 27,5 meters stud link anchor chain, diameter 24 mm. grade 2
1 high holding power anchor Kg 585
Total weight, anchor chains and fittings : 4887 Kg
Option B (Grade 3 + SHHP)
12 lengths 27,5 meters stud link anchor chain, diameter 22 mm. grade 3
1 Super high holding power anchor Kg 390
Total weight, anchor chains and fittings : 3958 Kg
The difference of weight between Option A and Option B is approx. 20% less and for higher equipment numbers even more.
* µ=µr µ0 (µr relative permeability) (µ0 permeability of free space)