Drilling carbon fiber masts

Drilling carbon fiber masts

Post by jack chalai » Fri, 14 Mar 1997 04:00:00


Quote:

> I need to install some masthead devices (VHF antenna, light) on our
> Freedom and am wondering about drilling into the carbon fiber mast.  Is
> there any special technique I should use to ensure a tight, long-lasting
> fitting?  Does drilling compromise the strength of the mast?

> Since the mast does not pass through the deck, I'll have to drill holes
> near the bottom (above the deck) as well.  I was toying with the idea of
> running the  wires (12V and antenna lead) down the outside of the mast
> along the external mainsail track (perhaps through a thin PVC channel),
> but can think of many more downsides to this approach than benefits.

> Any suggestions would be appreciated.

> Regard,
> Dave G.

Dave.....  Let me get this straight.  You've got a Freedom with an
unstayed carbon fiber mast and it is deck stepped???  I think you should
look again.  All the Freedom masts I've seen are keel stepped and you
can run the wiring right to the bottom of the bilge.  A light line with
a torpedo sinker dropped down through the top of the mast makes a good
messanger line to pull the rest through.

Jack
--

SV Hind Sight Doc# 691808 San Francisco, Ca.
         "Here we go again.  
    Change lightbulb....rewire boat"

 
 
 

Drilling carbon fiber masts

Post by Dave Grube » Sat, 15 Mar 1997 04:00:00

I need to install some masthead devices (VHF antenna, light) on our
Freedom and am wondering about drilling into the carbon fiber mast.  Is
there any special technique I should use to ensure a tight, long-lasting
fitting?  Does drilling compromise the strength of the mast?

Since the mast does not pass through the deck, I'll have to drill holes
near the bottom (above the deck) as well.  I was toying with the idea of
running the  wires (12V and antenna lead) down the outside of the mast
along the external mainsail track (perhaps through a thin PVC channel),
but can think of many more downsides to this approach than benefits.

Any suggestions would be appreciated.

Regard,
Dave G.

 
 
 

Drilling carbon fiber masts

Post by Al Gunth » Sat, 15 Mar 1997 04:00:00


Quote:

> I need to install some masthead devices (VHF antenna, light) on our
> Freedom and am wondering about drilling into the carbon fiber mast.  Is
> there any special technique I should use to ensure a tight, long-lasting
> fitting?  Does drilling compromise the strength of the mast?

> Since the mast does not pass through the deck, I'll have to drill holes
> near the bottom (above the deck) as well.  I was toying with the idea of
> running the  wires (12V and antenna lead) down the outside of the mast
> along the external mainsail track (perhaps through a thin PVC channel),
> but can think of many more downsides to this approach than benefits.

> Any suggestions would be appreciated.

> Regard,
> Dave G.

You need to ask Freedom. I understand they garantee the masts for the life
of the boat, but I'm not sure they want holes drilled in them. Maybe an
epoxied on mounting pad, but you need to ask first.
--
Al Gunther, Kingston, WA  <---- 47 52.65'N, 122 30.95'W
S/V "Corleto" - '81 Catalina 27
Building "Al's 26, a Pilothouse Sloop", Reviewed in WoodenBoat, Dec 1995

 
 
 

Drilling carbon fiber masts

Post by jack chalai » Sat, 15 Mar 1997 04:00:00

Quote:


> > Dave.....  Let me get this straight.  You've got a Freedom with an
> > unstayed carbon fiber mast and it is deck stepped???

> Jack -

> Thanks for the reply. Yes - it's a Freedom 21 (hinged mast, gun-mount
> spinnaker - remember those?).  I'm not familiar with other deck-stepped
> masts (this is the smallest boat I've sailed and the only one I've
> owned), but the C/F mast slides over a hinged "inner mast" which rises
> about two feet above the deck.  This inner mast then extends down
> through the deck to the keel.  Once rigged, it appears like a
> conventional keel-stepped mast (except the lower portion is all metal -
> not carbon fiber).

> Although the mast track is rivetted (sp?) to the mast without any
> apparent reinforcement, I will go with the collective recommendation
> here and contact Freedom before drilling.  In reality, what I want to do
> is relatively unnecessary - at 21' a masthead light is not required and
> I can always use a handhand VHF.

> Regards,
> Dave G.

I stand corredted Dave.  Forgot all about the 21.  He said red facedly.

Jack
--

SV Hind Sight Doc# 691808 San Francisco, Ca.
         "Here we go again.  
    Change lightbulb....rewire boat"

 
 
 

Drilling carbon fiber masts

Post by James Fry » Sun, 16 Mar 1997 04:00:00

Dave:

Although carbon fiber really is a great material for a mast, with many
advantages, it does have some drawbacks. Other than the obvious cost
issue, one disadvantage is that attachment points for all the fittings
are usually carefully considered in the design and building of the
mast. Areas where holes will be drilled are reinforced with a thicker
laminant called "doublers." Some builders put the doublers inside the
mast section and some on the outside. It can be very detrimental to
drill holes in the wrong places. Be very careful about this and
definitely check with the mast builder before proceeding.

Hardware is usually attached by first installing threaded stainless
inserts, we used "key inserts" on Cheyenne's mast, that are tapped into
the carbon and glued with epoxy. Hardware and fittings are then
securely screwed into the inserts. Drilling carbon will dull bits very
quickly. Titanium bits are recommended.  

Before drilling, you may first want to consider fabricating a
lightweight bracket that utilizes any existing fastening points at the
masthead. If that is not possible and the builder says do not drill
holes, you could laminate a doubler on the outside of the masthead area
and set the inserts in the doubler.

By the way, to protect the wires inside the mast, consider feeding them
inside a single braid spectra line rather than a PVC tube. Bungee tied
to a splice at the bottom of the spectra line works well to hold the
spectra line/wire harness snug.

Carbon is cool,
James
Cheyenne


writes:

Quote:

>I need to install some masthead devices (VHF antenna, light) on our
>Freedom and am wondering about drilling into the carbon fiber mast.  
>Is there any special technique I should use to ensure a tight,

long-lasting fitting?  Does drilling compromise the strength of the
Quote:
>mast?

>Since the mast does not pass through the deck, I'll have to drill
>holes near the bottom (above the deck) as well.  I was toying with the
>idea of running the  wires (12V and antenna lead) down the outside of
>the mast along the external mainsail track (perhaps through a thin PVC
>channel), but can think of many more downsides to this approach than
>benefits.

>Any suggestions would be appreciated.

>Regard,
>Dave G.

 
 
 

Drilling carbon fiber masts

Post by Dave Grube » Sun, 16 Mar 1997 04:00:00

Quote:

> Dave.....  Let me get this straight.  You've got a Freedom with an
> unstayed carbon fiber mast and it is deck stepped???  

Jack -

Thanks for the reply. Yes - it's a Freedom 21 (hinged mast, gun-mount
spinnaker - remember those?).  I'm not familiar with other deck-stepped
masts (this is the smallest boat I've sailed and the only one I've
owned), but the C/F mast slides over a hinged "inner mast" which rises
about two feet above the deck.  This inner mast then extends down
through the deck to the keel.  Once rigged, it appears like a
conventional keel-stepped mast (except the lower portion is all metal -
not carbon fiber).

Although the mast track is rivetted (sp?) to the mast without any
apparent reinforcement, I will go with the collective recommendation
here and contact Freedom before drilling.  In reality, what I want to do
is relatively unnecessary - at 21' a masthead light is not required and
I can always use a handhand VHF.

Regards,
Dave G.