MG 14 Flightspar MK II Mast Rigging Notes. (Dec 2000)

View diagram for mast detail.     Download file (.rtf)

The following rigging procedures may seem overkill to some people but the mast should stand the riggers of week in week out sailing.  It is the result of rigging around 100 masts over the last 15 years, and you should end up with a very stiff, lightweight mast around 7.4 kgs rigged.

Moving the hounds up takes the fulcrum point up, therefore reducing the lever pressure below the hounds.  I prefer to have a separate hounds fitting for the forestay which also spreads the load and reduces the fore & aft pre-bend.

I prefer double diamonds to give added support for the extra length created by moving the hounds up, the extra pressure created by the asymmetric spinnaker and the crew compression on the trap wire.

When ordering the Flightspar MK II kit, you won’t need the RF604 hounds fitting or the diamond wires if you use DYFORM as detailed here.  Order double diamonds & the heavy gauge rotator arms.

Hounds height 4130mm. (Bearing point)

Forestay height 3970 mm. (Bearing point)

Diamond tube lengths 180 mm long.  (You’ll need to cut these to length yourself.)

Diamond wire 2.5 mm x 3310 mm DYFORM.  We have found that Dyform will withstand the pressure created under spinnaker, by a 25 to 30 knot gust.  Previously 1x19 2.5 mm wires were breaking under this type of load. In fact I have rigged 3 masts over the 2 months that broke in this fashion.

As a guide for Aero 9, 10, 11;  Forestay length 4380 mm bearing point to bearing point, and Sidestay, 4300 mm BP to BP including large 6 mm D shackle.

Always use either monel or stainless steel rivets.

Always use either aircraft rigging paint or similar wherever the aluminium comes in contact with monel or stainless steel.

Always flush the entire mast inside & out with fresh water after sailing.  Nothing corrodes a mast quicker than salt water.

Step.

1. Make up a centering device by cutting a piece of your old mast
   
   
   
2. Cut a piece of your old mast to 500mm, cut the track off and slip it up the bottom of the mast.        Be sure to push it up about 30mm from the bottom or you won’t get the base plug on.
3. Cut a hole in the centre of the mast base plug to suit your mast pin setup, & tape it in the bottom of the mast.  All measurements are taken with the plug in to give uniformity and the correct height above the deck.  Don’t fix it yet, it will help you get the halyards etc. through.
4. Mark all the fitting points along the mast, i.e. rotator, diamond tangs, tee ball plates, diamond tubes & hounds fittings.
5. Drill 3/16 pilot holes through the mast for the diamond tubes and sight through to ensure you have measured it right.  Your eye should give almost perfect sight to see if you have drilled it square.  Gradually increase the size of the drill bit to 12 mm checking  for square as you go. This is the most important part of the mast rigging procedure.  You can use the drill bit as a sight gauge from the end of the mast. The final trim can be done with a round file.  You are now ready to fit the stainless steel diamond tubes. 
6. Cut and fit the tee ball backing plates and rivet in place.
7. Cut the diamond tubes to 180 mm long. Drill a 3mm hole in the end of each of the tubes and take them along to your marine supplier and have them make up the diamond wires with 2 tubes on each length. You won’t get “DYFORM” wires “through” the tubes if you don’t do this. Order the wire as shown below, cut & fit top tee ball first, then fit the diamond tubes and finally the lower tangs.  Put a nut on the end of the wires just enough to be secure, (say 3 turns) then lay the tang against the mast and pull some pressure on the wire.  Mark the hole for the tang and fix tang with a rivet in the top hole. Turn the mast over and do the other side.  Then drill a 3/16 hole through the bottom tang hole and fit a 3/16 bolt right through.  Don’t over-tighten.
   
8. Tighten up the diamond wires by putting pressure on the mast, i.e. set it up between two trestles, one at the bottom and one at the hounds.  Get someone to put their knee on it and bend the mast. Take up the slack on the rigging screw.  You could simply tighten the nut, but sometimes you can strip the thread.   The Dyform wire will only need about 3 or 4 turns to achieve a Loos gauge figure of 20, compared to about 12 turns using 1x19 wire.
9. Hounds fittings.  I prefer to use Riley RM 79 HD.  They may seem like overkill, but when you use your boat week in week out, there is no distortion in the fitting.  Put the eye end into a vise with a piece of cloth around it to protect it and bend the side tangs into shape with a pair of multigrips.  Use only as much twisting as you need to get the shape right.  You don’t need to fit them snug at the front provided they fold around neatly.  You can apply some silicone when fixing.  The more bending the weaker you will make it.  Fit over the mast and cut the excess tang off.  Drill a 6mm hole through each side of the fitting top line up with the centre line of the mast and then place on the mast and drill through the mast then roll over and do the other side. Fit a bolt through and carefully tighten with a nyloc nut, just enough to be taught.  Don’t over tighten.  Repeat the same procedure for the forestay hounds.
10. Rivet on the gooseneck fitting. Check the correct position by running the mainsail up the track and applying cunningham pressure.
11. Cut & fit the halyard sheave.
12. Line up the rotator and drill one 6mm hole.  Put the bolt in and lay the rotator along the mast track, then drill the other hole. This will give you a rotator perfectly centred.  You can also use stainless steel tangs to stop the wear and tear caused by the bolt.
13. Fit an RF 5 spinnaker halyard cleat or whatever you prefer.  You can drill a 6mm hole just above the rotator and adjacent the track to run the spinnaker halyard through.
14. Drill the main halyard hole, swage & fit the halyard wire, then fit the locking device at the bottom of the mast. Make sure you run the halyard down the inside back edge of the mast, i.e. along the track.  This is so you don’t foul up when hoisting the mainsail.
15. Cut the spinnaker halyard exit box and run the spinnaker halyard through.  I use a heavy gauge length of wire and tape the spin halyard to the end.  Makes it easier if you run the halyard through before you rivet the exit box in place. Make sure you run the halyard down the inside front edge of the mast and over the backside of the rotator.
16. Finally fix the base plug in place with a 3/16 bolt.  Make sure you drill off centre or you will foul on the mast pin.

Happy rigging.