Hi, and thanks for the positive feedback.

As I wrote in the first post of this thread, the alu plate on top acts as an equipment carrier: by fitting the Windex and other applications through this plate I won't have to puncture the actual mast top. I admit that by the heavy duty appearance of that alu plate it surely looks like being of structural purpose - but I didn't design it for that. I just got some leftover sheet in 5mm, though 1mm would have been enough. Only the grp structure should be more than sturdy enough. However, being connected by 7 M10 bolts, the plate now surely adds strength.

The ring bolt heads are just as wide as the washers, that's why I didn't bother. Also, later on the line loads will be pulling the ring bolts rather away from the grp surface. Surely, I could have formed some better fitting foundation for head and nut, with an even surface to distribute the loads evenly. But again, time flies and grp is strong enough.

As for cables: I don't run any cables up the mast by now, there is nothing electrical up there. However, if the future wants me to put up cables, I would of course run them inside the mast, and have one well sealed outlet at the mast top.

I will install a lightning rod, which will hopefully also deal with beautiful but unwanted winged visitors up there.

Hope to get the mast step ready this week, and also start painting. The temperatures are rising, finally.

Cheers,

Paul

Paul,

I struggle with understanding your use of that aluminium top plate. If that thing were mine, I would have removed those nuts in between and bolted the plate directly to the grp flange. Then the aluminium would also rest on the mast top and share the load with the flange.
I would also glue or solder a 50mm tall tube to the centre of the top plate. Into this tube I would insert a thin  (2mm?) wire, some 20-30cm tall, to discourage crows or seagulls from landing there. I would even tie a 20cm ribbon to its top, to help with reading the wind.

Arne

Anonymous wrote:

Short update on my grp mast head and collar design, see fotos attached. The masthead is glued only on the mast. The mast collar is epoxied onto the deck, and additionally secured with bolts.

Looks really good. This may be the route for me though my mast collar may be somewhat more complex. I will need to make a flat place for it first. Still, the basic idea will still work, I may end up building mine in place contiguous with the platform I need to build. Will you be adding rings to the mast collar bolts as well for pulleys? I was also surprised with the lack of washers behind the ring bolt heads but I have most experience with putting things in wood, which is "squishy" by comparison. You mentioned before not wanting to have holes in the top of the mast, how will you bring the cables you mention to the deck? Will you use a side hole in the mast out of rains way or run them on the outside? Personally, I wouldn't want to run cables on the outside of a JR as I am not sure there is any side of the mast where parrels or battens would not scuff or crush them. Inside seems to be the best place. I suppose hanging the cables from one of your rings outside the parrels would work but it would probably flop around banging the mast. Looks good so far, keep the pictures coming.

Short update on my grp mast head and collar design, see fotos attached. The masthead is glued only on the mast. The mast collar is epoxied onto the deck, and additionally secured with bolts.

Anonymous wrote:I formed 4 inverted triangles of epoxy and glassfibre reinforced with Kevlar at 90° intervals around the masthead. These supported a ring of 8mm stainless steel rod surrounding the masthead, on which lifts and halyards were hung. I believe it's worked well since it was done in 2011.

Now that, I would like to see more about. In some ways, I would guess aluminum would make more sense because I am using an aluminum pole. However, FG collars seem to be common for hybrid aluminum/wood or two tube masts so it makes sense and while I am not a FG professional, I have done a lot more FG work than aluminum work and probably have the materials just sitting here.

So I am thinking in my mind "inverted", does that mean pointy end up or down? Or in or out? I am guessing that the SS ring is left bare in the four places the triangles don't go and this bare SS is where things are hung from. But, I am less sure how the wide ends of the triangles are formed around the mast. Do they form a cup over the top?  Ah carbon fibre mast, maybe they are bonded directly to the mast? I don't think bonding directly to the mast would work very well with an aluminum mast but it seems FG would be strong enough from what you are saying, if some sort of top was added to make sure it did not slip down.