How to Fix a Bent Boat Mast

Written by will charpentier
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How to Fix a Bent Boat Mast
A stiff wind and full sail can bend an aluminium mast. (Thinkstock/Comstock/Getty Images)

It's a shipboard joke to tell a new seaman to find a "mast straightener," but straightening a bent mast takes just that, in the form of a specialised jig and a hydraulic jack. Trying to take the bend out of a sailboat's aluminium mast is a last ditch effort, one of those things that may work, and one that is as likely to end in the purchase of a new mast as it is in a straightened mast. If you do straighten the mast, though, you may find the project is worth the effort.

Skill level:
Moderately Challenging

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Things you need

  • 8-foot framing studs
  • 8-foot by 12-inch by 1-inch plank
  • 48 No. 2 Screws, 2 1/2-inches long
  • Drill
  • Screwdriver bit
  • Rebar
  • Hydraulic jack
  • Hammer
  • Nails
  • Adjustable wrench

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  1. 1

    Set two 8-foot framing studs on edge, parallel to each other. Lay an 8-foot-by-12-inch plank flat on top of them, positioning the studs so that they are even with the outside edges of the 6-inch wide plank.

  2. 2

    Drive number 4 screws, each 2 1/2-inches long, through the 6-inch plank and into the edges of one of the studs using a drill and screwdriver bit, so the stud is secured to the 6-inch plank by screws every 4 inches, . Repeat to secure both studs to the same side of the plank 8 inches apart, to form an 8-inch channel in which to lay the mast.

  3. 3

    Build a second jig, using more wall studs and another 12 inch plank. Secure one of the now-assembled mast jigs to the top of a work table.

  4. 4

    Insert lengths of rebar into the luff groove, the channel on the mast where the sail is secured. This prevents damage to the groove as the mast is straightened.

  5. 5

    Set the mast into the part of the wooden jig that's bolted to the table so that the bend is just beyond the end of the jig. Set the second, movable jig on the mast so the bend is between the two parts of the jig.

  6. 6

    Lay a closed hydraulic jack against the movable section of the jig. Temporarily secure a 12-inch length of framing stud to the work table to act as a "footer" for the jack to press on, using a hammer and nails.

  7. 7

    Operate the hydraulic jack slowly, taking care not to crack the aluminium mast. Attach an adjustable wrench to the edge of the luff groove, at the bend.

  8. 8

    Push the rebar from below the bend up into the luff groove, using the wrench as a lever to open the groove far enough to straighten the mast as you operate the jack.

  9. 9

    Continue to operate the jack until the mast is straight.

Tips and warnings

  • Straightening a mast is best described in the hackneyed phrase, "whatever it takes." The mast may be bent too much, the aluminium may have deformed or even broken when the mast bent.
  • Test the mast ashore, with a sail on and in a fresh breeze, before you return the mast to service.

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