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Measuring and Replacing Sailboat Lifelines | Expert Advice

Lifeline Components

Sailboat lifeline illustration

How do Lifelines Work

Lifelines work as a last resort system to keep a person on board a boat.  In the most extreme instance, imagine someone being washed by a wave from one side of the boat, across the deck and into the lifelines on the other side.  This can generate tremendous loads in the many thousands of pounds; therefore lifeline systems must be able to withstand high dynamic load and translate it directly to the stern and bow pulpits.  Lifelines should be taut over their entire length to ensure energy is immediately transferred to the pulpits.  Generally speaking if you take the longest unsupported length of the system (say two stanchions that are the farthest apart) and apply 10 pounds of force at the midpoint (midway between the two stanchions), the wire should deflect no more than 2 inches.  The tighter they are the better, as long as you are not bending your stanchion inboard or making gate eyes too difficult to operate.

In order ensure lifelines are properly tensioned over their entire length, they must be fully adjustable.

 

Lifeline Wire Types

Lifeline wire has traditionally been made of 7 x 7 stainless steel wire with a white vinyl coating.  The internal wire diameters have been 1/8″, 3/16″ and 1/4″ with corresponding outside vinyl diameters of 7/32″, 5/16″ and 3/8″.  Because the vinyl coating traps water, it causes the wire to prematurely corrode, and you cannot see the wire underneath the coating, so visual inspection is not an option.  Most offshore racing rules and regulations prohibit coated lifelines for these reasons.  APS only makes lifelines with uncoated 1 x 19 stainless steel wire which is available in 1/8″, 5/32″, 3/16″ and 1/4″ diameters.

Due to the smaller diameter of uncoated wire, some boat owners will upsize their lifeline wire diameter when replacing coated wire with uncoated wire to make it more comfortable when grabbed by hand.

 

Types of Lifeline Configurations

Illustration of sailboat lifelines with no gates

Lifelines with no Gates – One Section

These are the simplest lifelines.  Since the lifeline runs freely through the stanchions from bow to stern, it only requires one length adjuster.  A turnbuckle at one end (to adjust length) and a simple toggle jaw on the other.  You may substitute the toggle with a gate hook (pelican hook) at the pulpit to allow that area to be opened and the rest of the lifeline slackened for easy boarding and provisioning.  Another alternative is to substitute the toggle with a single gate eye to allow the life line to be lashed to the stern pulpit which allows for occasional opening of the life line by untying the lashings.  Lashings are done using small diameter (around 1/8″) line.  If you lash you lifeline to the pulpit, you will want to reduce the overall length of the overall lifeline length by 4″ (providing 4″ between the gate eye and the bail on the pulpit) to allow for the lashings.

Illustration of Lifelines with End Gates

Lifelines with End Gates – Two Sections

This configuration has two independently adjustable sections.  It is an easy way to create a gate while maintaining the safety provided by somewhat taut lifelines in the rest of the system when the gate hook is detached (unlike a one section lifeline with only a gate hook on the end that attach to the pulpit).  The interlocking gate eye does not allow the turnbuckle to tension the gate part of the lifeline.  Therefore your gate hook (pelican hook), which is adjustable, will be used for fine tuning the gate wire tension.

Illustration of Lifelines with Middle or Center Gates

Lifelines with Mid Gates – Three Sections

Boats designed for gates will have two stanchions approximately two feet apart to specifically accommodate a gate.  This minimizes the open area when the gate is open during boarding, and maintains the safety provided by somewhat taut lifelines in the other sections.  This requires all three sections to have independent length adjustment capabilities.  The turn buckle for the first section, then a gate hook (pelican hook), which is adjustable for the gate section, and an adjuster toggle for the third section.  Both the gate hooks and adjuster toggles have less than 50% of the adjustment range or throw of a turnbuckle, so they are use for short sections of the overall lifelines.  Turnbuckles with their increased adjustment range are used for adjusting the long section of the system.  On larger boats with longer overall lifelines, adjuster toggles may be replaced with turnbuckles.  This allows for a better range of adjustment for properly tensioning longer wire distances at both ends of the system.

 

Measuring Lifelines

What you will need

Preparing Lifelines for Measuring

Lifelines are measured off of the boat, but they must first be properly prepared on the boat, and then removed.  You will do so for both sides, port and starboard, as lifelines are not usually symmetrical.

  1. Ensure your pulpits and stanchions are not bent.  If they are, replace or have them repaired.  You want to make sure you are measuring lifeline lengths for properly configured supports and anchor points.
  2. Equally tension your lifelines over the entire system length on both the port and starboard sides.  Be sure that the load is traveling and transferring to the pulpits (not just against a stanchion).  Generally speaking if you take the longest unsupported length of the system (say two stanchions that are the farthest apart) and apply 10 pounds of force at the midpoint (midway between the two stanchions), the wire should deflect no more than 2 inches.  The tighter they are the better, as long as you are not straining your stanchion inboard or making gate eyes too difficult to operate.
  3. Mark the threaded stud against the fitting housing with tape, a Sharpie marker or measure the exposed threaded length with calipers.  Once you reassemble your lifelines off of the boat this will allow you to set the lifelines back to their proper length.
  4. Remove the lifelines one piece at a time by removing the adjusters and sliding the wire out of the stanchions.  Tag each piece of the lifeline using duct tape  as they are removed.  On the tag write 1) port or starboard 2) upper or lower 3) what piece it is in the system: forward, gate, aft.  Note: Masking tape and tied on tags can get ripped off when coiling and/or uncoiling the wires. 4) if you used calipers, the measurement of the exposed threads.
  5. Put the adjusters back on each piece of the system right after removing them from the stanchions.
  6. Coil each section and remove from the boat for measuring

 

Measuring Instructions

  1. Print out the APS Lifeline Measuring Sheet for the type of lifelines you have.
  2. Set adjusters to their marked or measured length and lock them in place with the set nut and/or pins.
  3. Record the wire diameter for the upper and lower separately on the sheet.
  4. Measure and record your lifeline lengths from bearing surface to bearing surface on the printed measurement worksheet. Please visit How to Measure Wire Rigging to ensure you are measuring from the bearing surface and see some of the methods of doing this.  Also, see how to measure lifeline sections with gate eyes and gate hooks below.
  5. For each section of the lifelines indicate the part number for the end fittings.  To do this, on the measuring sheet take the number next to the fitting in the illustration, and write ir next to the part number you wish to use.

 

Measurements for Lifelines with no Gates

Measurements for Lifelines with no Gates

A: Measured from the bearing surface of the turnbuckle to the bearing surface of the toggle.

Measurements for Lifelines with End Gates

Measurements for Lifelines with End Gates

A: Measure from the bearing surface of the toggle to the bearing surface of the gate eye (where the gate eye would bear against the stanchion).  Note that this requires that the gate hook (pelican hook) is attached to the gate eye while taking the measurement off of the boat.

B: Measure from bearing surface of the gate eye (where the gate eye would bear against the stanchion) – the same point as used in measuring the A section.

 

Measurements for Lifelines with Middle or Center Gates

Measurements for Lifelines with Middle or Center Gates

A: Measure from the bearing surface of the toggle to the bearing surface of the gate eye (where the gate eye would bear against the stanchion).

B: Measure from the bearing surface of the gate eye to the bearing surface of the next gate eye (where the gate eye would bear against the stanchion).  Note that this requires that the gate hook (pelican hook) is attached to the gate eye while taking the measurement off of the boat.

C: Measure from the bearing surface of the gate eye (where the gate eye would bear against the stanchion) to the bearing surface of the toggle.

 

Ordering New Lifelines

By website order:

  1. Add all needed lifeline fittings in your online cart
  2. Add the lengths of  1 x 19 wire you will need, port and starboard, upper and lower.  This is done by simply totaling all of your lengths and entering that one amount
  3. Add the part called I Would Like to be Contacted about Rigging in my Order to your cart.  You many attach a short message to this part.
  4. Check out online.  We will not charge your card nor start your order until we have first talked with you.
  5. Scan and email us your completed measurement for to SAIL@apsltd.com.  Please reference your order number in the email.
  6. We will contact you the next business day to confirm your order and give you a day definite ship date.

By Phone:

  1. Call us to place your order
  2. Be ready to read off the information on your measurement sheet.
  3. We will confirm your order on the phone and give you a day definite ship date.

By Shipping us Your Lifelines:

  1. If you are not comfortable taking your own lifeline measurements, please ship your existing lifeline to us after following the instruction in the ‘Preparing Lifelines for Measuring’ above.
  2. We will contact you to confirm your order and give you a day definite ship date.

* Allow us one week to measure your lifelines

 

If you have questions or are unsure about something; call, email, or live chat us before you place an order for rigging. We’re happy to answer any questions you may have

Photos Courtesy of C.Sherman Johnson Co. Inc.

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