Welcome
Over the past 45 years I have had the pleasure of designing an unusually wide variety of boats of all sizes – both sail and power-driven (see https://nigelirens.com/), but right now we are concentrating on spreading the word about a particular kind of power-driven boat – the development of which has been an on-going passion of ours since 2003.
These designs are characterised by the fact that their hulls are unusually long for their displacement. From the outset we therefore adopted the term ‘LDL’ (‘Low Displacement/Length ratio) to identify this kind of vessel. In the case of the ‘LDL’ hull our clear objective has always been to optimise a range of speeds that lie anywhere between slow speed (the easy bit…) up to ‘swift’ speeds up to about 12-14 knots – beyond which planing-hulled designs will be more appropriate – especially if these speeds are needed for much of the time afloat.
Early in the 2020 it became obvious that the characteristics we had optimised with the development of the ‘LDL’ hull made it a perfect partner for the burgeoning development of electric propulsion. The problem bothering the world of planing-boats is that the inherently low energy-density offered by a battery often results in serious power-to-weight problems when compared to traditional gasoline-powered units that have always served the high-speed boating industry so well.
It’s clear from the above that there is an obvious symbiosis to be explored between ‘LDL’ boats (like ‘CLARA’) and the needs of the outboard engine industry with a view to offering boats that appeal to those who value the pleasure of travelling at ‘swift’ speeds (as opposed to ‘fast’ ones) in a silent boat that poses no threat to the environment in which it travels.
NIGEL IRENS
Summer 2026
These designs are characterised by the fact that their hulls are unusually long for their displacement. From the outset we therefore adopted the term ‘LDL’ (‘Low Displacement/Length ratio) to identify this kind of vessel. In the case of the ‘LDL’ hull our clear objective has always been to optimise a range of speeds that lie anywhere between slow speed (the easy bit…) up to ‘swift’ speeds up to about 12-14 knots – beyond which planing-hulled designs will be more appropriate – especially if these speeds are needed for much of the time afloat.
Early in the 2020 it became obvious that the characteristics we had optimised with the development of the ‘LDL’ hull made it a perfect partner for the burgeoning development of electric propulsion. The problem bothering the world of planing-boats is that the inherently low energy-density offered by a battery often results in serious power-to-weight problems when compared to traditional gasoline-powered units that have always served the high-speed boating industry so well.
It’s clear from the above that there is an obvious symbiosis to be explored between ‘LDL’ boats (like ‘CLARA’) and the needs of the outboard engine industry with a view to offering boats that appeal to those who value the pleasure of travelling at ‘swift’ speeds (as opposed to ‘fast’ ones) in a silent boat that poses no threat to the environment in which it travels.
NIGEL IRENS
Summer 2026
