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Mast & Boom Work


While the mast was down on Mikhaya in Nov-Dec 2003,
I decided to clean it up and renew some fittings.

The 1979 Mast

 

 


The Mast Measurements

Pictures 1 - 26 below show the mast with a tape measure in the picture, starting at the base plate.  Starting at the top left, zoom in to get a good picture of the tape measure location and find any item on the mast.  Sorry the tape measure is upside down.
 

5-4-3-2-1 (base)

10-9-8-7-6

15-14-13-12-11

20-19-18-17-16

25-24-23-22-21

26 (head)

Some common points on the mast as measured from the base:

To VHF Antenna Top        41'-4"

To Lightning Rod Top       40'-0"

To Anchor Light top          39'-5"

To Top (mast it's self)       39'-0"

To top black strip             37'-11 1/2"

To Lazy Jacks Block        25'-2"

To Steaming Light            20'-9"

To spreaders center         19'-10 1/2"

To winches                        3'-2 1/2"

To goose Neck                  2'-11"

Bottom Black Strip             2'-4 1/2

 

From the Web Site of Rig-Rite

 

(The Kenyon Spars 5072, came the closest to the actual mast that I had on Mikhaya)

Kenyon Spars 5072 Mast Section


Kenyon Spars 5072 Mast
Measurements (outside): 7.40" x 5.08"
Wall Thickness: .156"
Weight/ft.: 3.9 lbs.
Moments of inertia: Ixx = 21.3", Iyy = 11.5"
Circumference: 20 9/16"
Alloy: 6061-T6
Sail slides: 15/16" flat slides (A008M)
Internal Electrical slides: K-10908
Standard lengths: 45'7", 48', 51'

Kenyon 5072 Mast Section

 

 


The Base Plate

                   

 


The Boom Measurements

Pictures 1 - 12 below show the boom with a tape measure in the picture, starting at the mast end.  Zoom in to get a good picture of the location and measurement for any item on the boom.

5-4-3-2-1

10-9-8-7-6

12-11


Some common points on the mast as measured from the boom.

Total end-to-end                 15'-10"
Total aluminum boom          15'-6"

Main sheet attachment        15'-5"

To black strip                     14'-9 1/2"

Reefing Cleat 1                  13'-11 1/2"

Reefing Cleat  2                 12'-11"

Sail Cart Track                   10'-1" - 12-1/2

Downhaul                             3'-8"

Cleats                                  3'-6"

Cleats 1                               3'-3"

 

 

From the Web Site of Rig-Rite

 

(The Kenyon Spars 3756, came the closest to the actual boom that I had on Mikhaya)

Kenyon Spars 3756 Boom Section


Kenyon Spars 3756 Boom 
Measurements (outside): 6.00" x 3.75"
Wall Thickness: .130"
Weight/ft.: 2.4 lbs.
Moments of inertia: Ixx = 8.3", Iyy = 3.6"
Circumference: 15 13/16"
Alloy: 6061-T6
Sail slides: 3/4" flat slides (A006M)
Standard Boom Lengths: 11', 16'6"

Kenyon 3756 Boom Section

 


New Boot

 
The mast boot was topped and slid on before stepping the mast.


     After stepping the mast, the top part of the boot was secured by a large hose clamp, folded down and secured at the bottom by a

second hose clamp.  Finally the excess was trimmed off.  This same mast boot could also be put on with the mast up.  A small tube of glue was included to re-seam the boot after cutting it.

 


Cleaning and Waxing

The 1979 mast was ionized so the cleaning process was to use a good scrubbing pad and some powered Aluminum cleaner.  Worked very well and cleaned up nicely.

 

   

     After a good clean up, a wax job was in order.  I think between Pam and Matt, they got five coats on the mast and boom.  They used that 3M expensive wax stuff.

 

I touched up the black paint on the cleats, sail gate, black stripes
and mast base.  The boom had a new paint job on both
ends as well as the cleats.

 

 

 


New Steaming Light

  
 

The original steaming light from Pearson was hard to change the bulb.  So I upgraded and included a deck light also.  My son is drilling and tapping the mounting. 

 

From the Net!

Installing Hardware on aluminum Spars

A pro reveals the secrets to successful drilling, screwing and tapping.


Lightning Spike and Cable

See Lightning Protection

 


New Standing Rigging

See Standing Rigging

 


Checking out the Mast Wiring

  

 

The mast wiring was renewed five years ago and was in good shape.  I replaced the anchor light globe, the VHF Antenna, installed a lightning spike, cleaned and sealed the wind vain plug and installed new spreader lights.  Before stepping the mast I measured the current load on the lights and did a continuity check for the wind vain cable.

Continuity Check:

  • Using the Data Marine Wind Vain cable, I grounded one lead at at time to the mast at the base of the mast.

  • At the mast head, I grounded one lead of the ohm meter to the mast.

  • Using the other lead of the ohm meter I probed the Wind Vain connector to find the wire I had grounded at the mast base.

  • I checked out all 7 wires, including the shield.

 

Current Load Reading:

  • I used 12v dc from my car and connected it up so that my amp meter was in series with the load (anchor light, spreader light, etc).  The car was handy and near the mast stands.

  • The current loads were as follows...

    • Anchor Light        - 0.903 amps

    • Steaming Light     - 2.310 amps

    • Spreader Lights   - 4.580 amps
       

Mast electrical cables inside of the mast:

     The mast cables were secured inside of the mast with plumbing pipe insulation tubes.  They worked quite well and provided cable protection while reducing the noise inside. 


Other Ideas from the Net on Securing Cables in the Mast

 

Curing "Mast Rattle"

 

Mast Wiring on a Prout Catamaran

 


Mast Head, Port & Starboard

       

The mast head was cleaned up and reworked.  The head pulleys were cleaned and refitted.  See New Halyards Project.

 


Spreader Details

 

The spreader mounting plate is 7 1/2" x 3"

 

The large end of the spreader is 3".

The length of the spreader is 42 1/2".

  The light is mounted 19 1/2" from the base.

    The spreader bulb is a GE4411

 


Don't Forget the Sail Track

I wiped out the sail track with turpentine

and sprayed it with Sail Track.

Mast Finished and Ready to Step

   

See Removing and Stepping the Mast


Reconnecting the Mast Wiring

    

   The holes in the deck for the mast cables were already drilled by the previous owner.  They were not sealed and water did leak at times.  I choose to drill out the old balsa wood and seal the holes up.  I had a tube of marine silicon that had been sitting around for a while so I decide to use it up in stead of epoxy the holes.  The 5/8" sanitary hoses were fitted over the mast outlets and the mast wiring pulled through the hoses to inside of the head.  I had just enough inside diameter to fit all five cables.  The hoses were cut to length and the wiring pulled down inside of the "pole cover," to under the sink.  The final two picture show the completed job inside and on the deck.

 

 Installing the VHF Coax Connector

 

             1                2                 3                 4                5

            6                 7                8                  9              10

                             11               12               13

     After connecting the mast, installing the mast wiring through the deck and down the inside of the head wall, it's time to connect up the wiring to the terminal blocks and install the connectors on the VHF antenna cable.

 

1  Strip off about an inch of outside insulation on the RG-213 coax.

2  Cut the center connector insulation back exposing the center

    conductor.

3  Fold back the shield and trim back.

4  Install the connector (Amphenol RFX)and by twisting it on with a pliers.

5  Solder the center conductor.

6  Check to see if the shield and center connector are shorted.

7  The RF cable from the radio is now connected to the mast

    antenna by use of an RF bullet.

8  The Shakespeare Meter for measuring Fw and VSWR

    (reflected) power.  Lets you know the condition of the Radio,

    RF Cable, Connectors and Antenna.

9  Forward Pw measurement. 

10 VSWR measurement.

11 Rf Cable supported up.

12 The Mast Lighting DC block and below the Data Marine Wind

     Vain connection block.

13 The Lightning cable exiting from the mast support post and

     going down to the hull ground plate.

 


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