24ft Trimaran in Oz

LOL....yeah the sciatica is playing up today. I noticed that although I'd covered the main hull cockpit, the undecked port hull was collecting rainwater, so a mate and I moved it into the yard today and put it up on trestles to drain and dry out.

Luckily it's been epoxied at least one coat inside, so no harm done (fingers crossed)

 

Cheeky ******* !

 

This is the tape it appears Roger was using to strengthen the internal joints of the beams.

It has a product code on a tag inside the reel - CGH175 - which an internet search indicates is a carbon-strengthened fibreglass tape normally used for the edges of surfboards.

Is this the right product for the job he was using it for? Seems it's designed to add strength along the line of the tape but also to flex.....???

Any thoughts?

 

Being as its bi axial as opposed to double bias 50% of the fibre is parallel to the joint - not optimal.
Double bias at +45-45 would be what I would use along joints/connections.

 

Yeah, that's what I was thinking.

So can I just go over the top of what's already been done with bi-axial, or do I need to grind it all out?

 

Looking at that tape again it appears that the carbon is going to be parallel so not much use.
You wouldn't have to grind it out it looks pretty light but........
If you want to keep it light every little gain helps.
And get yourself some peel ply.
Oh and what you have is biaxial, what you want is double bias.

 

Yeah, sorry, meant double bias - biaxial is what the Seppos call it...

Peel ply. Yep. Need that. I believe it's other name is "polyester taffeta"..???

Sure I read that somewhere...

 

Double bias +45-45
Biaxial 0-90 - What you have, standard weave of woven cloths etc

Double bias can be bought as cloth or tape and is usually stitched rather than woven, keeps the fibres straight which is stronger.

Peel ply, I've never used it from outside the fibreglass industry so get advice elsewhere, I believe it is suit lining fabric ? Different weights/weaves behave differently as peel ply, as in being difficult to absorb resin or difficult to peel. I believe its much cheaper outside the grp industry, just make sure you know what you are buying.
Perhaps someone else can advise ?

 

I was quoting form BoteCotes website, as below. Maybe that's what caught Roger out...reading American plans?

"Double Bias has about half of its fibres laid at 45 degrees to the length of the cloth (+45 degrees) and the other half of its fibres at right angles to the first lot, and they are thus also at 45 degrees (-45 degrees) to the length of the roll. It has similar uses and strength to Biaxial. It is often used to cover joints between panels so that fibre crosses the joint. In the US, double bias is also called biaxial. This is a problem for Australian builders using plans from the US as they often are not aware of this."

Would appreciate some further opinions on peel ply, as it's stupidly expensive from GRP suppliers

 

Well I learnt something today !

 

http://www.boatdesign.net/forums/search.php fiberglass and composite boatbuilding forum: peel ply

 

http://www.boatdesign.net/forums/search.php materials forum: peel ply

 

Aha! The old "use the search function trick"!

Why didn't I think of that, 99??

 

buzzman

come out of that man cave and tell us where you are at !

 

Coping with sciatica and a crook back.....caused by manually removing a large garden bed that was preventing the gate from opening wide enough, and thus preventing me getting the boat and trailer into the yard.....

Like I said, progress is slow.....