Laser mast rake explained

Laser mast rake explained

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Mast Rake 2016 by Chris Caldecoat

New worldwide builders target is set at 3815mm, previously the target was 3825mm

Following data collected at the ISAF Worlds it was noted that the average mast rake was 3815. Actually all boats in the STD Fleet were around this number, meaning that sailors where seeking boats at this rake as it was not the build average.

Data collected from Radial Sailors ordering new boats also showed this to be a good average.

Measurements you need to know.
– To measure the rake you will need a Std Rig section, it must measure 2855mm in length.
– Measure the rake from the outside edge of the bottom section ( see pictures below ), if you use this you will be able to refer to the production yards measurements.
– A new boat can move by up to 4mm in rake following a few sails. (can and aft)
– The boat is 8mm wider on the Stb side. Forget measuring side to side.(they are all like this World wide) A quick check is measure to the corner of the stern, if it is within 5mm of each other your          mast is in the middle of the boat ( inside 5mm means your mast is inside 1mm either side of centre )

Mast wear strips change your rake…. If you put one at deck level and one on the bottom of the mast you will lift your mast 10mm in rake. I have tested this and learned the hard way with my daughter sailing her 4.7, she was not happy with her boats performance change.

One important measurement to keep in mind, 1mm difference at deck level equates to 6.5mm on the final rake measurement.

Note that nearly all PSA boats are within 6mm of 3815 these day’s, so our rake tolerances are very tight.

Yes they are One Design !


How to measure your rake….

Once you have your std section rigged up with a tape on the outside edge, (can be easier to put the tape on 100mm to start and subtract off the total) take the following steps.

*Ensure you have the correct length bottom section when measuring any rake – the section should measure 2855mm
rake3

  1. Mark the stern as follows, 35mm aft from the Stb deck tread, this will put the mark in the middle of the Radius.rake2
  1. Place the std bottom section in the mast post and pull your tape firmly, measure your rake to the point you have just marked on the radius ( make sure you subtract the 100mm off the total ). You can and we even do in the factory get slightly different measurements depending on who is pulling on the tape. So just be firm, it’s not a backstay. Make sure your section has not been sitting in the sun heating up when measuring your rake, you will get a slightly different outcome, we have tested and proven this.rake1This one measures at 3815mm which is right on target ( take the 100mm off the total as mentioned above )

Latest go fast rakes by me.

Laser 4.7

57kg crew

3822 to 3824

Minimum bend Bottom section ( 72mm ) and Max Heavy Top section, (kill for a 3kg section)

You want as much leach tension as possible. (note, the Vang loads on a 4.7 are higher than a Radial, so harder for the kids to pull on, remember that when coaching and work around the sailor if they are having issues pulling on enough Vang)

Laser Radial

3811 to 3818

“New Radial composite bottom section coming is awesome” (made by PSA).

Laser with new STDMkII sail

For me, (master) 90kg to 92kg – 3814

83kg about 3808.

If you are a good young fit hiker creep it up to 3812 to 3814. (*new laminate has also dropped the rake, stiffer boat)

*There is a new Hull Laminate in all new Lasers, LP started this a little before PSA, we started it in Jan of this year. Hulls are a lot stiffer and the lumps and bumps gone.

by Chris Caldecoat

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