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Old 08-07-2017, 16:44   #1
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Fiberglass Spreeders?

One of my 4 spreaders is probably going to be due for replacement in the not too distantant future due to some wood rot.

I was wondering about makeing some new ones out of solid fiberglass but I havent seen any so maybe theres a good reason there arent any.

I have seen wood / aluminum / steel

Any opionions or expericence ?

Thanks
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Old 08-07-2017, 21:22   #2
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Re: Fiberglass Spreeders?

I am not saying you couldn't make them out of fiberglass, but they would need to be incredibly large. Spreaders work almost completely in compression and fiberglass just doesn't have the stiffness to work well. It's the same reason you don't see fiberglass masts.

Wood is fine, aluminium is standard, carbon works and saves weight which is critical up the mast but comes with a heavy price penalty.
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Old 08-07-2017, 22:14   #3
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Re: Fiberglass Spreeders?

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Originally Posted by Stumble View Post
I am not saying you couldn't make them out of fiberglass, but they would need to be incredibly large. Spreaders work almost completely in compression and fiberglass just doesn't have the stiffness to work well. It's the same reason you don't see fiberglass masts.

Wood is fine, aluminium is standard, carbon works and saves weight which is critical up the mast but comes with a heavy price penalty.
I wasn't aware that it shouldn't be done, so I made mine out of two pieces of 1/2", 6 lb pvc foam laminated together with 3 layers of 18 oz roving and 2 layers of 1.5 oz mat, shaped into an oval cross section about 5" x 1" at the base and 2.5" x 1" at the tip, with filled inserts for through bolting, laminated and vacuum bagged outside with iso polyester resin and 2 layers of 18oz roving and one layer of 1.5 oz mat. Filled with glass beads and resin, sanded and coated with 2 part acrylic urethane paint. Haven't been in victory-at-sea conditions with them, but they've held up so far....about nine years...but the compression forces may be a real reason not to follow my example.
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Old 08-07-2017, 22:46   #4
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Re: Fiberglass Spreeders?

Properly designed, they can certainly handle compression loads without being giant. In fact, carbon fiber's big advantage is in tension, not compression, so if those work fiberglass should be fine.

The only catch is you need to understand the loading both on the overall spreader and within the parts of your new fiberglass model. (also, I would suggest replacing them in pairs, if not all of them, so the strength is symmetrical).
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Old 08-07-2017, 23:31   #5
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Re: Fiberglass Spreeders?

Can't see why not. People build fibreglass forebeams for Cat's which handle much bigger loads.
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Old 09-07-2017, 03:49   #6
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Re: Fiberglass Spreeders?

They'll just be heavier than same-strength aluminum. But for a project that small, the difference in price for carbon might be worth it. If you make it mostly of unidirectional fibers, with some woven cloth as first and last layers to hold it all together, it could be awesome. Soller Composites sells woven hollow sleeve material that would be perfect for that.
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Old 09-07-2017, 09:14   #7
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Re: Fiberglass Spreeders?

Quote:
Originally Posted by jimbunyard View Post
I wasn't aware that it shouldn't be done, so I made mine out of two pieces of 1/2", 6 lb pvc foam laminated together with 3 layers of 18 oz roving and 2 layers of 1.5 oz mat, shaped into an oval cross section about 5" x 1" at the base and 2.5" x 1" at the tip, with filled inserts for through bolting, laminated and vacuum bagged outside with iso polyester resin and 2 layers of 18oz roving and one layer of 1.5 oz mat. Filled with glass beads and resin, sanded and coated with 2 part acrylic urethane paint. Haven't been in victory-at-sea conditions with them, but they've held up so far....about nine years...but the compression forces may be a real reason not to follow my example.
For a 33' boat a 1" thick spreader is massive. That is a massive amount of windage to put that high in the air. Not to mention the weight.

But like I said, they can work, it just really isn't the right material for the job.
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Old 09-07-2017, 10:20   #8
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Re: Fiberglass Spreeders?

Yes this is for a 53ft boat and the spreaders are fairly large.

I didnt think so much of the weight issue though I doubt it will add much to the already 20tons.

Just dont want mast failure is all.

What if I put some carbonfiber matting between ever few layers of fiberglass?
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Old 09-07-2017, 11:12   #9
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Re: Fiberglass Spreeders?

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For a 33' boat a 1" thick spreader is massive. That is a massive amount of windage to put that high in the air. Not to mention the weight.

But like I said, they can work, it just really isn't the right material for the job.
They are exactly the same size as the teak spreaders they replaced, and though I didn't weigh them, I'm sure they're at least 30 percent lighter...windage isn't too much of a concern (to me at least), given the substantial windage already present, though those with racing or fast cruising pretensions might think otherwise. With a 49 year old boat and limited financial resources (not to mention a conservative [in the true sense of the word] nature and an insatiable desire to build stuff) t'was the best solution for me...far be it from me to specify what the 'right material' for a job is...
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