Prototype Foot Strap Design Considerations for Surf Lifesaving Inflatable Rescue Boats: Technical Report #7 to Surf Life Saving New Zealand (SLSNZ)

Grobelny, M
Reay, S
Diewald, SN
Hume, P
Wilson, BD
Wooler, A
Merrett, R
Smith, V
Item type
Commissioned Report
Degree name
Journal Title
Journal ISSN
Volume Title
SPRINZ, Auckland University of Technology

Background: Foot straps have been removed from IRBs due to concern they were causing lower limb fractures due to entrapment with rotation during landings. Purpose: To model possible positions and prototype designs for foot straps in IRBs. Methods: Strap measurements were taken from the SLSNZ boat in Raglan, then modelled with the alternatives to give an overview of possible placement for one person. Foot strap prototyping was conducted using 3D modeling with an initial EVA material design constructed.
Results: A number of questions were identified that need to be researched to provide information for the design brief including: Can feet be parallel, or is it important for them to be staggered; Does the right foot do most of the work?; Which positions cause injuries?; Without a foot strap, how likely are the feet to bounce up away from the deck in big swell? Three foot strap concepts were modelled: Camlock adjustment; Quick release/pressure release clasp; Raised foam strap. A prototype EVA pad with strap was built. A moveable track with cam lock was conceived. Discussion: Foot placements needed to be adjustable for varying lower limb lengths. Foot straps need to be adjustable for varying foot sizes. Key priorities for design of the foot strap system include: Minimal fixtures; No hard/sharp edges; Keep boat deck flat without raising foot hold areas; Quick and easy to adjust; Strong enough to handle impacts and weight of crew; Positionable for shortest to tallest crew member; Ability to swap out strap to renew; Corrosion resistant. Review of all the project reports identified that ensuring three points of contact for the crew with the boat was important as a consideration for the phase II design project. Conclusions: Further testing is needed to assess foot placement as the current positions are not yet researched. Discussion on the pros and cons of the suggested foot strap prototypes is needed followed by construction and in‐the‐boat testing.

Grobelny, M., Reay, S., Diewald S.N., Hume P.A., Wilson B.D., Wooler A., Merrett R., Smith, V. Prototype foot strap design considerations for surf lifesaving inflatable rescue boats: Technical report #7 to Surf Life Saving New Zealand (SLSNZ). SPRINZ, Auckland University of Technology, 16th July 2019. 8 pages.
Publisher's version
Rights statement
Auckland University of Technology (AUT) encourages public access to AUT information and supports the legal use of copyright material in accordance with the Copyright Act 1994 (the Act) and the Privacy Act 1993. Unless otherwise stated, copyright material contained on this site may be in the intellectual property of AUT, a member of staff or third parties. Any commercial exploitation of this material is expressly prohibited without the written permission of the owner.