Hello everyone,

I'm new in the forum, and already have my first question :-)

Who is able to do me a non-binding rough breaking-strength calculation for following sailing-boat-part made of carbon? Example pic at the end of this text.

It is about a so-called BOWSPRIT pipe (for the gennaker sails).

I'd like to change my old aluminum one for a carbon one.

My old aluminum tube has 8.5kg incl all fittings. The carbon tube only 2.5kg.
I haven't used it yet. I would like to ask forum experts first.

Conclusio should be: Is the carbon tube sufficiently dimensioned or at least as stable as the one made out of aluminium?

I have following info for you:

old aluminium tube:
- alloy: probably AlMgSi0,5
- Length: 2,300mm (approx. 1 meter boom, the rest is screwed on deck with 2 clamps)
- outer diameter: 80mm
- Inside diameter: 72mm
- Wall thickness thus: 4mm
- Weight of the pipe without fittings approx. 8 kg

Carbon tube:
pullwinded
- Length: 2,300mm (approx. 1 meter boom, the rest is screwed on deck with 2 clamps)
- outer diameter: 80mm
- Inside diameter: 76mm
- Wall thickness thus: 2mm

fiber alignment: Unidirectional inside + 75°/35° outside
fiber volume: aprox. 60 %
surface: smooth, shiny
temperature resistance: up to 110 °C
tensile-E-Modul: 240.000 MPa
tensile strength: 4.000 MPa
fracture strain: 1,50%
density: 1,8/cm³
thermal expansion coefficient: -0,1 * 10-6*K-1 along the fiber
radiolucent: 100%
specific elctrical resistance: 1,6*10-3Ohm*cm
heat conductivity: 17 [W/(m*K)]
specific heat capacity: 710 [J/kg*K)]
no vibrations
UV-resistent by using standard varnish
corrosion-resistent: e.g. petrol, oil, saltwater, hydrofluoric acid
handling: drill, mill, cutt, glue 

weight: approx. 1kg per meter

Would be super nice of you if you could help me

Many thanks in advance

Hi Oekmot,
Thanks  for  your  detailed response.
Here some more pictures.


  NOT teflon but NYLON !








I hope this helps to understand the  functions