NZQA unit standard / 15454 version 4
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Title / Demonstrate knowledge of trailer boat propeller operation, types, servicing, and installation procedures
Level / 3 / Credits / 4
Purpose / This theory-based unit standard is for people in the trailer boat repair industry. People credited with this unit standard are able to demonstrate knowledge of: propeller function and operation; propeller types and terminology; and propeller servicing.
Classification / Motor Industry > Trailer Boat Systems
Available grade / Achieved

Guidance information

1 Definition

Service information may include but is not limited to – technical information ofa vehicle, machine, or product detailing operation; installation and servicing procedures; manufacturer instructions and specifications; technical terms and descriptions; and detailed illustrations. This can be accessed in hard copy or electronic format and is normally sourced from the manufacturer.

2 The following website publication may be useful as reference material when completing this unit standard:

Everything you need to know about propellers, available at: http://sites.mercurymarine.com/portal/page?_pageid=126,48572,126_49259_dad=portal&_schema=PORTAL.

3 This unit standard can lead on to Unit 15465, Check and determine the suitability of a propeller for a trailer boat.

Outcomes and performance criteria

Outcome 1

Demonstrate knowledge of propeller function and operation.

Performance criteria

1.1 The role of a propeller is described in relation to a boat’s handling and performance.

Range transmitting power from the engine to the water, causing movement to the boat.

1.2 The operation of a propeller in the water is described in accordance with service information.

Range water flow past the blades, negative pressure and positive pressure creating thrust.

Outcome 2

Demonstrate knowledge of propeller types and terminology.

Performance criteria

2.1 Types of propeller are identified in accordance with service information.

Range type of hub, type and number of blades.

2.2 The differences between left and right hand propellers are identified in accordance with service information.

Range rotation, blade position.

2.3 Parts of a propeller are identified in accordance with service information.

Range blade face, ribs, leading edge, hub, shock absorber, diffuser, diverging ring, converging ring.

2.4 Types of blades are described in accordance with service information.

Range constant pitch, progressive pitch.

2.5 Propeller diameter is identified from a diagram.

2.6 The purpose of cupped blades is identified, and how cupping increases rake angle is described in accordance with service information.

2.7 Blade rake is identified from propeller diagrams, and the purpose of rake is described in accordance with service information.

Range positive, nil, negative.

2.8 Operation of diffuser, diverging, and converging ring is described in accordance with service information.

Range outboard through hub exhaust.

Outcome 3

Demonstrate knowledge of propeller servicing.

Performance criteria

3.1 Limitations to propeller repairs are identified in accordance with service information.

Range blades, hub.

3.2 Procedures to measure a propeller are identified in accordance with service information.

Range diameter, pitch, coding.

3.3 Detrimental effects of water flow past a propeller are identified in accordance with service information.

Range ventilation, cavitation.

3.4 Propeller installation procedures are described in accordance with service information.

3.5 Procedures to repair propeller assemblies are described in accordance with service information.

Range blades, hub, shaft.

Planned review date / 31 December 2019

Status information and last date for assessment for superseded versions

Process / Version / Date / Last Date for Assessment /
Registration / 1 / 23 February 1999 / N/A
Revision / 2 / 16 April 2003 / N/A
Review / 3 / 21 September 2007 / N/A
Rollover and Revision / 4 / 20 July 2017 / N/A
Consent and Moderation Requirements (CMR) reference / 0136

This CMR can be accessed at http://www.nzqa.govt.nz/framework/search/index.do.

Comments on this unit standard

Please contact the NZ Marine and Composites Industry Training Organisation if you wish to suggest changes to the content of this unit standard.

New Zealand Marine and Composites Industry Training Organisation
SSB Code 101812 / Ó New Zealand Qualifications Authority 2017