What material for a spare wind vane for self steering?

[MM5AHO]

I have a self steering system, and the detachable wind vane is sure to be dropped overboard one day. So far not, but it seems inevitable. Less likely but possible is that it gets broken.
It appears to be made of something like a 3mm double sided formica.
I don't see any materials like this often. Any ideas on a source?

 

[rogerthebodger]

I made mine for a 2 layer polycarbonate roof sheeting

Like the top pic

Very rigid, light and strong

I made mine from clear and 4 mm overall thickmess

 

[sarabande]

Do you have any GRP engineering firms nearby ? They may have an offcut of the dimensions you need.

 

[Prasutigus]

Greetings..
Varnished marine plywood is the Aries way, but it's about 6 mm thick, that method might not fit, if yours is really as thin as 3 mil. (3 sounds jolly thin I must say).
What about a kitchen laminates wholesaler, I'm fairly sure you can get laminates laser-cut to a CAD drawing quite cheap.

(And you would have a choice of colours, such as Taupe, Aubergine, Pink Sunset, Misty Mountain Mauve, Dawn Oyster, the list goes on.)

 

[Poignard]

I made mine for a 2 layer polycarbonate roof sheeting

Like the top pic

Very rigid, light and strong

I made mine from clear and 4 mm overall thickmess

That's the sort of thing my Monitor vane is made of. I think it's about 10mm thick.

 

[Kurrawong_Kid]

I had one made up of carbon fibre.

 

[BobnLesley]

...the detachable wind vane is sure to be dropped overboard one day...

We do carry a spare Monitor plywood balde aboard, but a small hole drilled through the blade close to the bottom/leading edge with a light and loose line connecting that to the windvane's frame has had no noticable effect on performance and has caught the blade on the couple of occassions when I've dropped it.

 

[Poignard]

I haven't got my Monitor manual handy but I seem to remember reading that a replacement vane can be made from plywood with most of the centre cut out and replaced by light cloth glued in place to keep the weight to a minimum. Wasteful of plywood but probably much cheaper than having a vane airmailed from the USA.

 

[macd]

Whatever the material, it's crucial that the overall weight of the vane, and its distribution, is similar to that of the original.

 

[ghostlymoron]

Traffolite?

 

[ghostlymoron]

How about using a lanyard?

 

[MM5AHO]

Thanks for a few ideas.
Not sure that a lanyard would do the job of something designed to catch wind.
Ply is common on some systems that use a thicker material, but 3mm ply is going to be rather weak I think. The existing material (original) looks looks formica, but is the same on both sides. It's white outside and a laminate of perhaps 3 layers with a brown (paxolin etc) inner. It is 3mm thick. I think the bracket that takes the wind vane might stretch to take something wider. The polycarbonate material looks a good idea. I might also try aluminium sheet.

 

[macd]

I might also try aluminium sheet.

If thick enough to be sufficiently rigid, you might find that would be overweight. Despite it's reputation for lightness, Al has similar density to concrete.

 

[penberth3]

Foam board used for temporary road signs, mounting artwork etc., might work. Available in various thicknesses.

 

[MM5AHO]

Yes, aluminium would be approximately double the density of the current vane. (2.7 vs 1.35). Might be a bit much when the vane tips well over, might be less inclined to return to vertical.

 

[PuffTheMagicDragon]

Surely there is a counterweight that can be adjusted?

 

[macd]

Surely there is a counterweight that can be adjusted?

Surely there's no 'surely' about a wind-vane system of unknown make?

 

[rogerthebodger]

Yes, aluminium would be approximately double the density of the current vane. (2.7 vs 1.35). Might be a bit much when the vane tips well over, might be less inclined to return to vertical.

A piece of leftover UPVC fascia board cut to the right size may also do the job.

The honeycomb polycarbonate is very strong and light but easy to cut with a wood saw and wood drill.

http://www.sbfltd.co.uk/upvc-fascia-boards.htm

 

[MM5AHO]

Surely there's no 'surely' about a wind-vane system of unknown make?

Seafeather.

 

[Pye_End]

Seafeather.

I made up a spare out of fairly thin ply (get the grain the right way round and it seems sturdy enough). Weight seems ok. If I was going big blue then may well ask Seafeather for a spare.