Licensed to a manufacturer

Outdoor Gear Design: Fall Arrest Hunter Safety Device

Item: LA New Product Development Team
Rating: 5
Author: James McMaster

INDUSTRIAL DESIGN
MECHANICAL ENGINEERING
MECHANISM DESIGN
PROTOTYPING
TESTING & VALIDATION
DESIGN FOR MANUFACTURING
LICENSING SUPPORT

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Written by Konstantin Dolgan, Ph.D., NPDP

Founder & CEO, Product Development Engineer

Published August 30, 2026

Outdoor gear design is product design for equipment used in the field — cold, wet, dark, carried on a person and operated without a bench or a manual. It combines industrial design, mechanical engineering and hard field testing, because the environment, not the spec sheet, decides whether the product works.

Fall Arrest, by McMaster Outdoors, is a personal fall arrest device for hunters in tree stands. LA NPDT took it from James McMaster's idea through design, centrifugal brake engineering, multiple tested prototypes and design for manufacturing — and the finished product was licensed to an established manufacturer.

Project at a glance

Client: James McMaster, CEO of McMaster Outdoors
Product: Fall Arrest — personal fall arrest device for hunters in tree stands
Scope: Concept and industrial design, mechanical engineering, centrifugal brake design, prototypes, testing, design for manufacturing
Starting point: An idea with no drawings, models or prototypes
Key mechanism: Centrifugal brake — free line at climbing speed, locking under fall speed, with an energy-absorbing lanyard
Outcome: Manufacturing-ready design licensed to an established manufacturer

What the client said

★★★★★

“Great and easy to work with. They allow you to turn your vision and design into reality. My prototype came out great even after I pivoted on the design a few times during the process!”

James McMasterCEO, Fall ArrestGoogle review

A tree stand fall arrest device taken from a hunter's idea to a manufacturing-ready product that was licensed to an established manufacturer.

The client

Fall Arrest, by McMaster Outdoors, is a personal fall arrest device for hunters who work from tree stands. It straps to the trunk above the stand, pays out line freely while the hunter climbs and settles in, and locks the moment the line runs out at fall speed — so a slip ends with the hunter hanging in a harness instead of hitting the ground.

James McMaster came to LA NPDT with the idea and nothing else. Our team took it through concept design, industrial design and mechanical engineering, designed the internal braking mechanism, built and tested successive prototypes, absorbed several design pivots along the way, and finished at a manufacturing-ready design. Rather than tooling up himself, McMaster licensed the finished product to an established manufacturer in the hunting market. It is one of several outdoor and hunting product development programs run out of our Ruston, Louisiana shop.

The challenge

Falls from tree stands are the most common cause of serious hunting injury, and bow hunters are especially exposed because they climb early, climb in the dark and move around at height with their hands full — a pattern documented across published trauma reviews of tree stand fall injuries. The engineering answer already exists in construction, where self-retracting lifelines are standard personal fall arrest equipment governed by OSHA 1926.502. The problem is that a construction unit assumes things a hunter cannot provide.

The anchor is a tree, not structural steel. The device had to clamp and strap to an irregular, moving, growing trunk and stay put across a season.
It is carried, not installed. Weight and bulk are budgeted against what a hunter will actually pack in before dawn along with a bow, a stand and a pack.
It is used one-handed, in the dark. Attaching, paying out and detaching had to work by feel, with gloves on, without reading anything.
The field is not a job site. Cold, rain, mud, sap and a full off-season in a garage all had to be survivable.
It has to stay quiet. Anything that clicks, rattles or shines costs a hunter the animal, which means the device does not get used.

Bow hunter seated in an elevated tree stand connected to a Fall Arrest device strapped to the tree trunk above him — In use: the unit straps above the stand and stays connected while the hunter climbs, sits and shoots.

Our solution

Engineering the Braking Mechanism

The heart of a fall arrest device is a brake that ignores slow motion and reacts instantly to fast motion. We designed a centrifugal mechanism: shoes carried on a rotating hub are held inward by springs, and the drum turns freely while the line pays out at climbing speed. In a fall the drum spins fast enough that centrifugal force overcomes the springs, the shoes swing out against the drum, and the line locks.

Sectioned CAD render of the Fall Arrest centrifugal brake showing shoes, return springs and friction drum — Sectioned view: shoes, return springs and the friction drum they engage.

CAD render of the assembled Fall Arrest centrifugal brake unit with carrier plate and pivoting shoes — Sectioned view: shoes, return springs and the friction drum they engage.

Two numbers set the whole design. The engagement threshold has to sit above the fastest speed a climbing hunter will ever produce and below free-fall, or the device either locks on every step or fails to catch. The arrest itself then has to be soft enough not to injure the person it just saved, which is what the energy-absorbing lanyard below the housing is for — it stretches under load and spreads the stop over distance instead of stopping the body in an instant. Spring rate, shoe mass, pivot geometry and friction material were sized together against those two targets, then re-checked against cold weather, where springs stiffen and grease thickens.

Top view CAD render of the Fall Arrest brake showing three pivoting shoes and their return springs around the hub — Three shoes and their return springs set the engagement threshold.

Exploded CAD render of the Fall Arrest brake assembly showing fastener, washer, shoe, friction pad and drum — Three shoes and their return springs set the engagement threshold.

Prototypes, Testing and Design Pivots

A safety device cannot be argued into existence on a screen. We built working prototypes, dropped weights on them, and used what happened to change the design — several times, including pivots the client asked for once he had a unit in his hands. Each round tightened the same short list: does it lock at the right speed, does it survive the shock, does the housing hold up when it is dropped, and can a hunter operate it wearing gloves?

James McMaster holding a working black prototype of the Fall Arrest hunter safety device by its carabiner — A working prototype — the point at which a drawing becomes something you can test and argue with.

From Working Prototype to a Product a Manufacturer Would Take

The last stretch was design for manufacturing: converting the tested prototype into moulded parts with sensible draft and wall thickness, standardising fasteners and springs to catalogue parts, cutting assembly steps, and packaging the drawings, bill of materials and test results into something a manufacturer could quote and build without redesigning it first. Where a client wants to make and sell the product themselves, the same package feeds our low-volume manufacturing line instead.

Angled render of the Fall Arrest device showing the tree strap routing through the back of the housing — The strap routes through the housing so the unit sits flat against the trunk.

The result

McMaster Outdoors ended the project holding a proven, manufacturing-ready design rather than a garage full of inventory. That package was strong enough to license the product to an established manufacturer already selling into the hunting market — the fastest route to shelves for a solo inventor, and the outcome we aim at whenever a client would rather collect royalties than run a supply chain. Similar field-gear work includes the Bait Bunker and the DropTine scent dispenser.

Industrial design and CAD. Housing, strap routing and control geometry, modelled and rendered for review and marketing.
Mechanism engineering. Centrifugal brake sized to an engagement threshold, with an energy-absorbing lanyard for a survivable arrest.
Tested prototypes. Working units built, loaded and revised across several rounds, including client-requested pivots.
Manufacturing package. Mouldable geometry, catalogue hardware, drawings, bill of materials and test results.
A licensable product. De-risked enough for an established hunting-market manufacturer to take on.

Working on outdoor, hunting or safety gear and want the same path from idea to a licensable product? Talk to our Ruston, Louisiana team or start with our product development process.

Capabilities used on this project

Rapid prototyping services
3D printing, CNC machining, urethane casting and functional prototype builds with published materials, tolerances and lead times.
Concept design
Sketch exploration, form studies and CAD concepts that turn an idea into a buildable direction.
Design for manufacturing
Molding-ready geometry, tolerances, production drawings, assembly documentation and DFM review with the tooling vendor.

How a piece of outdoor safety gear gets developed

Borrow the proven mechanism from industry, then re-engineer everything around it for the way the product is actually carried and used.

Start from the proven industrial mechanism
Self-retracting lifelines are mature, regulated equipment in construction. Beginning there means the physics of arresting a fall is not being invented — the work is adapting a known mechanism to a new user and a new anchor.
Re-specify the product around the field, not the job site
A tree is an irregular, moving anchor. The user is carrying a bow at 5am in the cold, wearing gloves, and cannot make noise. Each of those becomes a hard requirement that changes mounting, weight, controls and materials.
Engineer the brake to two numbers
Engagement speed must sit above the fastest climbing motion and below free-fall; arrest force must stay low enough not to injure the person caught. Spring rate, shoe mass, pivot geometry and friction material are sized together against those two targets.
Prototype and drop-test, then let results change the design
Working units get built and loaded rather than simulated into approval. Several rounds — including client-driven pivots after handling a prototype — refine lock speed, housing durability and one-handed operation.
Convert the tested design into something a factory will quote
Mouldable geometry, catalogue springs and fasteners, fewer assembly steps, and a package of drawings, bill of materials and test results — the form a manufacturer or licensee can act on without redesigning it.

Three routes for an outdoor gear inventor

Route	What it does	Where it falls short
Copy an industrial device and rebrand it	Gets a working mechanism to market quickly	Ignores the anchor, weight, noise and weather realities that decide whether hunters carry it
Overseas factory design service	Produces samples cheaply against a brief you supply	Assumes the safety engineering is already correct and rarely supports load testing or a licensing package
Engineering-led outdoor gear design	Derives the mechanism, materials and controls from field use, then proves them in tested prototypes	Costs more up front than a copy; justified when the product carries a safety claim

Rapid prototyping services Design for manufacturing Our product development process

Questions about this project

Straight answers from the engineers who ran the build. Have a different question? Ask us directly.

Talk to an engineer

What is outdoor gear design?

It is product design and engineering for equipment used outdoors, where cold, water, dirt, portability and one-handed operation are requirements rather than nice-to-haves. It pairs industrial design with mechanical engineering and field testing, because failures show up in use rather than on a drawing.

How does a fall arrest device for hunters differ from a construction one?

The anchor is a living tree instead of structural steel, the device is carried in rather than installed, it is attached in the dark with gloves on, and it has to stay quiet enough not to spook game. Those constraints change mounting, weight, controls and materials even though the internal braking principle is shared.

How does the braking mechanism work?

Spring-loaded shoes ride on a hub inside a drum. At climbing speed the springs hold them in and the line pays out freely; in a fall the drum spins fast enough that centrifugal force throws the shoes outward against the drum and the line locks. An energy-absorbing lanyard then softens the stop.

Can LA NPDT take a hunting product from idea to manufacturing?

Yes — that is what this project was. McMaster Outdoors arrived with an idea and left with a tested, manufacturing-ready design, having gone through concept design, engineering, prototyping, testing and design for manufacturing with one team.

What does licensing a product to a manufacturer involve?

Instead of tooling up and selling it yourself, you hand a proven design and its documentation to a company already in that market and earn royalties. It requires the design to be de-risked — tested prototypes, clear drawings and a bill of materials — which is exactly the package a development project should end with.

Industries this project belongs to

See how we approach development in each of these categories, and the other products we have taken from sketch to production there.

Sports & FitnessProduct development services

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Project at a glance

Engineering the Braking Mechanism

Prototypes, Testing and Design Pivots

From Working Prototype to a Product a Manufacturer Would Take

Capabilities used on this project

Rapid prototyping services

Concept design

Design for manufacturing

How a piece of outdoor safety gear gets developed

Start from the proven industrial mechanism

Re-specify the product around the field, not the job site

Engineer the brake to two numbers

Prototype and drop-test, then let results change the design

Convert the tested design into something a factory will quote

Questions about this project

Industries this project belongs to

DropTine Scent Dispenser: Design and Manufacturing

Bait Bunker: Outdoor Product Design

Elevating Precision in Putting Practice

Tell us what this is about