Catalogues - propellers-and-propulsion-system



	The sea of gold - propeller finishing. Destroyer escort Hers manufactured from nickel aluminium bronze The end result is spectacular!
		Fremantle Port Authority Safety Vessel fitted with VEEM propulsion


materials			dynamic balancing facilities

Propellers are offered with a variety of material specifications, including aluminium, manganese bronzes, nickel aluminium bronzes (NiBrAl) and stainless steel. While aluminium and manganese bronzes offer less expensive options for general use, nickel aluminium bronze offers increased strength and reduced drag due to thinner for boat blades. Nickel aluminium bronze provides excellent resistance to corrosion, errosion and fatigue, while being easily repairable. Our Foundry Division is able to alloy all of its own metals using our NATA (National Association of Testing Authorities) certified laboratory to provide chemical analysis to assist in meeting any material specification required.			Dynamic balancing is integral to VEEM's propeller manufacturing. Propellers are balanced to a very high standard using either ISO 1940/1 G2.5 or G6.3, and all propellers that leave VEEM have a balance certificate on record. Dynamic balancing is particularly important for high speed vessels to ensure that our high performance designs are accompanied by excellent smoothness.
			propeller balancing notes
			Caution must be taken when balancing marine props due to the critical nature of blade for boat cross sections, and the effect that this has on thrust (dynamic load) during operation. When balancing propellers, the allowable residual unbalance as defined by ISO 1940/1 should be calculated by taking into account shaft bearing spacings and propeller added mass (due to entrained fluid). As propellers are generally balanced between machine pedestals for boats, but operate as an overhung rotor, the allowable unbalance is commonly miscalculated. Of major concern is that by far exceeding the required balance standard, vibration can be introduced due to the effect of dynamic forces generated by distorted blade profiles. This introduced vibration greatly exceeds any benefit gained by reducing the unbalance in air. This provides a sound reason as to why balance standards for marine propellers should not be exceeded.
propeller repair services
In addition to its manufacturing capabilities, VEEM offers repair and refurbishment services for fixed pitch and controllable pitch propellers. During periodic servicing, propellers are sent to VEEM for de-fouling, cleaning and inspection and the propeller is returned to an as new condition. Depending on client requirements, the propeller may be completely checked for profile and dynamically balanced prior to being fitted to the marine ship.