Kiwiprop - SDC 3 bladed prototype

The photoes below show an initial 3 bladed prototype 18" diameter.
Targeting the newer 40 hp Volvo D2-40 and 55 hp D2-55 Saildrives.

Units not yet available for sale

With the advent of slower running 3000 rpm engines of increased horsepower now becoming available on Saildrives up to 75 hp,

there is a requirement for Saildrive propeller units with larger blade areas and diameters than can be provided with just 2 blades.

Typically, this unit will target the newer 40 hp Volvo D2-40 and 55 hp D2-55 Saildrives.

These will generally be fitted into larger vessels where displacements are higher thus requiring the additional blade area.

Basically, the blade area required is a function of displacement - and thus there will be some overlaps between this 3 Bladed unit at the top of the 2 Bladed and at the bottom of the 4 Bladed range.

The solution adopted is to install 3 SDC x 2 Blades on a slightly larger boss which has the effect of increasing the diameter as well as increasing the blade area by 50 % while retaining all the known and attractive characteristics of the smaller 2 bladed SDC unit.

Thus by utilizing the same 17" blades we obtain a 3 bladed ~ 18" propeller with all the same functionality, and in particular attractive economics of the SDC 2 bladed unit as no additional dies or inventory are required.

The body of the unit that holds the blades is obviously new, along with a new internal boss to accommodate the modified internal drive.

However, apart from the spline attachment - the component stress levels are no greater than in a 2 bladed unit.

Following successful tests of 2 bladed units up to 36 hp - it is reasonable to conclude that this larger unit will accommodate ~ 55 hp.


Viewd from forward facing aft
blades feathered

Viewd from aft
Blades feathered

Viewd from side
blades feathered

Viewd facing forward
blades open


Kiwiprop - SDC 4 bladed prototype

The photoes below show an initial 4 bladed prototype 19" diameter.
targeting the newer 55 hp Volvo D2-55, the 75 hp D2-75 and Yanmar 4JH4 and 4JH3-T of similar power.

Units not yet available for sale

Typically, this unit will target the newer 55 hp Volvo D2-55, the 75 hp D2-75 and Yanmar 4JH4 and 4JH3-T of similar power.

These will generally be fitted into larger vessels where displacements are higher thus also requiring the additional blade area from 4 blades.

The solution adopted is to pair 2 x 2 bladed SDC units on a slightly larger boss which has the effect of increasing the diameter as well as doubling the blade area while retaining all the known and attractive characteristics of the smaller 2 bladed SDC unit.

Thus by utilizing the same 17" blades we obtain a 4 bladed ~ 19" propeller with all the same functionality, and in particular attractive economics of the SDC 2 bladed unit as no additional dies or inventory is required.

The body of the unit that holds the blades is obviously new along with a new internal boss to accommodate the additional internal drive mechanism.

However, apart from the spline attachment - the component stress levels are no greater than in a 2 bladed unit.

Following successful tests of 2 bladed units up to 36 hp - it is reasonable to conclude that the larger unit will accommodate ~ 75 hp.