DuFLEX vs Aluminium
Based on ATL’s experience engineering vessels in composite, we have found the weight saving possible, over a fully optimised 1 aluminium structure, is a minimum of 30%.
This weight saving is based on an E-fibreglass laminate on DuFLEX. Further weight saving could be possible, at increased expense, through a move to carbon fibre laminates on the DuFLEX panels. In some stiffness critical applications it can be practical, and be reasonably economical, to make this decision.
1 The critical detail here is ‘fully optimised’, as most aluminium superstructures have a lot of dead weight due to the need for minimum plate thicknesses to facilitate welding.
Based on the design safety factors in codes such as DNV-GL or Lloyds Register, a composite structure will theoretically last an infinite period of time, provided it is maintained appropriately i.e. painted surfaces are always maintained to prevent UV degradation of the under-lying composite laminate, and damage is addressed in a timely manner, etc.
There is nothing unusual or outside of the normal maintenance program on an aluminium or steel vessel, for composite vessels. If anything a composite structure requires significantly less maintenance, as it does not have any corrosion issues.
The life of a steel or aluminium structure is typically determined during their 5 year periodical surveys, by measuring the remaining plate thickness in hulls, and strength decks. The composite laminates on a DuFLEX sandwich panel will not change, therefore it can offer a life far in excess of an aluminium or steel structure.
The life of a vessel can be designed to any requirement and is a function of the Fatigue characteristics under a given load.
An extreme example of composites ability to perform under continual load is wind turbine blade applications – these items have blade lengths in excess of 40m and have a minimum 20+ year design life. Fatigue is the driving design criteria in these structures.
ATL Composites has also engineered DuFLEX Composite Panels into bridge applications where the requirement is 100+ years, and rail applications at 40+ years.
The design life of DuFLEX will therefore be in excess of an aluminium vessel designed to the same conditions.
There are also many associated additional benefits in using DuFLEX Composite Panels over aluminium for boat construction. Inherent insulation qualities associated with the core materials which eliminate condensation risk on the inside of the structure will also provide less power load when cooling. Other benefits include sound and vibration dampening.