ROD AND WIRE RIGGING LIFE EXPECTANCY

The most prominent factors that affect the longevity of rod and wire
rigging are:
1. Length of time / miles that the yacht has been in service.
The more usage the yacht gets the more frequently inspections
should be done.
2. Breaking strength / load ratio.
The closer the actual loads the rigging encounters are to the rated
breaking strengths, the shorter the life expectancy.
3. Predominant sailing conditions.
If the yacht is frequently sailed in heavy air conditions, the life of the
rod or wire will be shorter than if the boat is sailed infrequently, or in
lighter wind conditions.

4. Frequency of care and maintenance
If the rigging has been periodically checked, the end fittings rinsed
with fresh water, and general care and maintenance have been
employed, it will last longer.
5. Environmental conditions
Where the rigging is constantly subjected to an environment
with substantial air pollution, airborne contaminants will shorten the
mast system’s life span. Frequent cleansing and inspection
is recommended.
6. Rod passes routine inspections
If the rod passes a Level C inspection, the rod may last an additional
20,000 to 30,000 miles. Navtec recommends rod re-heading and a
stringent maintenance and inspection schedule.
7. T-hooks
Due to the design, the life expectancy of the T-hook is much
shorter than rod or wire rigging. They should be diligently inspected
and replaced.



Mast System Inspection Categories

LEVEL A
Visual Inspection with Mast In

LEVEL B

Visual Inspection with

Mast In - Jack Down

LEVEL C

Full service with Mast Out

Comprehensive general mast system visual inspection

Pre-check rig to assess service

(Level A Inspection)

Pre-check rig to assess servicing schedule

(Level A Inspection)


Check all fittings/terminations, rod/fiber/wire, spreaders,
sheaves, halyards, headstay, backstay, mast base, partners,
haylard blacks and chainplates

Un-jack mast
Un-step mast
Check for cracks, corrosion, pitting, rust
General visual inspection
Complete disassembly of mast/fittings
Service log/update schedule for next service

Check for bends/kinks in

fittings and rod

Visual Inspection. Clean/polish rod, cold heads and fittings
to facilitate inspection process. Visual inspection for cracks,
corrosion, pitting, rust, general discoloration: remember rust
indicates cracks


Check/lubricate all accessible

fittings

Non-Destructive Testing (NDT) of Rod. Navtec recommends:
Dye penetrate testing (liquid penetration testing) by
authorized professional. Alternative methods: x-ray,
ultrasound testing, eddy current testing


Properly re-tune to align and seat all cold heads and hardware, and generate proper tension/tuning
Visually inspect and Safe Working Load (SWL) pull test all fiber rigging

Service log/update schedule for next service
Make repairs as needed: re-head rod, replace any fittings or rigging screws


Reassemble mast system


Update service log/update schedule for next service


Re-step/re-tune mast


RECOMMENDED MAINTENANCE INSPECTIONS

Mast system inspections should be conducted regularly and schedules should be based on the size and general

classification of your yacht. Controlling variables are displacement and type of usage. Heavy displacement yachts falling into Category I & II will have different inspection criteria based on tensile fatigue issues rather than those of category III & IV, which will base inspection intervals on usage and potential Safe Working Load issues. The following inspection scenarios should be implemented based on general usage and predominant sailing conditions. At a minimum, Navtec recommends a Level A mast system inspection at least once a year, regardless of yacht classification category.

YACHT DISPLACEMENT CLASSIFICATIONS

The marine technical monitoring group, Germanisher Lloyd, has put together the following outline chart outlining yacht classifications,with input from Navtec and other mast and rigging suppliers. These different displacement categories will tend to experience different usage,mileage and sailing conditions. Full inspection intervals will vary depending on which category your yacht falls into.

CATEGORY III & IV

Light and ultra light displacement yachts generally have different sailing characteristics (e.g. mast bend and rake), and use higher loading scenarios with smaller rod in their rig plans than heavier
displacement yachts. These working issues will potentially generate
higher loads on the rod and fittings than published Safe Working Load. It is not unheard of for racing yachts to operate at 40-50% of the breaking strength of the rod. This creates a shorter working life in the rod and fittings and
should refl ect in the frequency and intensity of the maintenance and inspection schedule for your yacht. Frequent inspection is necessary and will guarantee that any problems are caught before they become catastrophic.


CATEGORY I & II

Heavy displacement sailing vessels, (i.e. large cruising yachts or super yachts), have a different criteria for general rig inspections because they tend to accumulate many more miles than typical racing yachts.The same is true, but to a lesser degree, for mid displacement yachts.Also, the useful lives of heavy displacement sailing vessels tend to be
much longer than the normal useful (competitive) life of racing yachts.For this reason, rigging design generally shifts toward longevity rather than ultimate performance concerns.These concerns stem from the fact that these yachts generally do not bend their masts significantly to control sail shape. Many use simple marine eye and toggle terminations, which are heavier than typical high-performance fittings but have much better alignment capabilities
under load. In these cases, bending stresses are minimal, and the controlling failure mode frequently shifts to simple tensile fatigue.If failure occurs, tensile fatigue failures generally occur after a much larger number of loading cycles than bending fatigue failures. Large cruising yachts and super yachts frequently sail 15,000 to 30,000
miles per year and can reach large mileages quickly, leading to the possibility of tensile fatigue failure.
As a result, maintenance and inspection issues shift into a slightly different schedule and mindset as Safe Working Load (SWL) issues are not the primary concern.

care & maintenance

CATEGORY
DISPLACEMENT CHARACTERISTICS
TYPICAL PURPOSE CHARACTERISTICS
TYPICAL HANDLING CHARACTERISTCS
I
Motor Sailor/Heavy Cruiser
Ocean Going
Handled by Crew
II
Mid Displacement
Offshore
Handled by Crew, Owner or Shorthanded
III
Light Displacement
Coastal Pleasure Cruising/Club Racing
Handled by Crew, Owner or Shorthanded
IV
Ultra Light Displacement
Racing
Handled by Professional Crew


Navtec Recommended rig care

Performance, reliability, and safety depend on routine mast and rigging inspection schedules, whether you are a
cruiser or an America’s Cup contender. The following information and guidelines outline a recommended service
schedule, are an introduction to rod, wire, and fiber rigging life expectancy, and answer some general questions
regarding maintenance.

351 New Whitfield St Guilford, CT 06437-3400  USA   (203) 458-3163 Fax (203) 458-9291    info@navtec.net