Epoxy rod for compression post (keel stepped mast)

[steve1963]

At some stage, I will probably have to replace the compression post in the mast foot of my keel stepped mast. Currently, (as far as I can see ) there is a short ss tube, about 7cm X15cm from the mast foot down to the bottom of the bilge/top of keel.

I was wondering about the possibility of replacing the metal tube with a solid rod of epoxy/glass of similar or larger dimensions. Anyone know whether glass/epoxy would resist the compression forces?

Boat is a SHE 33.

Any comments/suggestions welcome

 

[Refueler]

GRP rod tends to splinter when compressed - it has incredible compressive capability of course - but that splintering is due to the glass filaments used in the construction

My question would be - what is wrong with the SS in place now ?

If its a position that is not needed for access to keel / bolts etc - then why not create a platform and mast key ? I suppose the tube allows cables etc to exit ?

 

[LittleSister]

I don't know about a tube, but I've read of people replacing a failed wooden base on which a keel stepped mast sits with a block built up from the hull with glass/epoxy. That would be easier to fabricate, if you have room to do similar, and even have a projecting cylinder or cylindrical indentation if either of those is required to locate the mast foot.

Alternatively, a solid grp/epoxy cylinder would be stronger and easier to fabricate than a tube.

 

[steve1963]

GRP rod tends to splinter when compressed - it has incredible compressive capability of course - but that splintering is due to the glass filaments used in the construction

My question would be - what is wrong with the SS in place now ?

If its a position that is not needed for access to keel / bolts etc - then why not create a platform and mast key ? I suppose the tube allows cables etc to exit ?

The ssDNA looks to be corroded. It's actually very difficult to see for sure, as the access is truly awful. I will only really be able to tell by unstepping the mast. If it is in good condition, I will, of course, leave it in place

 

[rogerthebodger]

I would go for a mild steel square tube about 100 mm square and have it galvanized. The bae of the tube I would fit into a pad made of GRP or Epoxy to prevent corrosion

My deck stepped compression post is made of galvanized tube in a doorway frame to allow easier access to the front cabins

 

[Daydream believer]

Links time out for me

 

[rogerthebodger]

Links time out for me

Hope that now works

 

[Refueler]

I don't know about a tube, but I've read of people replacing a failed wooden base on which a keel stepped mast sits with a block built up from the hull with glass/epoxy. That would be easier to fabricate, if you have room to do similar, and even have a projecting cylinder or cylindrical indentation if either of those is required to locate the mast foot.

Alternatively, a solid grp/epoxy cylinder would be stronger and easier to fabricate than a tube.

As I suggested earlier ... a platform style rather than a tube - much easier to create ... and far better in taking the loads without any splintering etc.

 

[Neeves]

I suspect fibre glass, or the resin, will creep under compression and you will be constant re-tuning the mast.

I'd go for a solid block of hard wood or a steel fabricated support, as Roger suggests or in stainless (as you may find it difficult to have steel galvanised).

Jonathan

 

[Chiara’s slave]

You could have a creep free one made of carbon. It’s not expensive these days. But, as others say, unless ypu’ve got some compulsion to save weight, what’s the point? Down there, weight is giving you righting moment. You could probably make a more useful part out of depleted uranium than GRP or carbon.