I want to make up a new cradle for 3394, as the existing one is broken. My plan would be to make up a 'mould' using the actual hull section and some ply, and use GRP. But never having done any fibre glassing before, are there any good tip sheets around
- I presume polyester resin, lot cheaper than expoxy- how much for a cradle 1kg, 2 kg?
- Chopped strand or woven mats, if so what density?
- I presume I done care about a gell coat as I will have carpet or astro turf glued on top, am I right?
any tips guys?

Chop strand and polyester is cheap and will surfice. Lay an old bit of carpet over the hull and some plastic sheet over that. It keeps the heat generated by the resin going off away from your paintwork / gelcoat and also when you glue your atroturf or carpet onto the finished cradle, the cradle matches the hull shape better.

I did this last year for 3078 which has just come out of retirement.  I used about 2.5 litres of polyester and el-cheapo glass fibre.  Turned the boat upside doown, layed a doormat over it and painted with GRP.  Worked fine but I learned some lessons.

-Don't use carpet if it is a natural material as it will rot.  B&Q sell some rubber backed nylon doormats, quite expensive, but much better.

-Protect your paintwork well - it is a messy job.

-think about the edges.  Do not paint right up to the edge of the mat as it will scratch the boat when you launch.  The downside is the edges will tend to curl up rather than down thus preventing a snug fit.  Not sure how to prevent this.

- make sure you've thought through how you are going to attach the cradle to the trolley.

- Consider putting some rigidity in it.  My trolley-dolley pulled it out of the water from the middle and turned it inside out.

- 5 layers should be enough

Mine worked well, except that I had to wrap something around it afterwards as I ended up with some sharp edges.

If you lay some paper rope between layers it will make the structure more rigid.

SOverign trailors supply cradles at about £60 why bother making one

Tempted as I am to buy, WAPB is one of 4, and the existing cradle doesn't fit well (CT/NSM4 shape) and that probably why it is broken, an dth elaunching trolley isn't a soveriegn, so it would be about £100 by the time they weld up supports in the right place. Plus it sounds like fun doing something new!

p.s. whats paper rope?

Try a cling film layer to prevent sticking to the mat!

Made a glass cradle for 3133 about 15 years ago and it is still going strong.  Used cheap strand glass and resin from a car repair supplies. Lay strip of tinfoil over upturned hull - it conforms perfectly to the shape shape.  Half a dozen or more layers, glass in the supports that fit to the trolley (I left the trolley attached so the fit would be perfect, remove before completely hard, trim edges to size on a band saw and you have a customised glove fit.  I laced carpet over the cradle for protection.  About one to two hours and maybe 25 quid.  I wish all the repairs/upgrades to the boat since had gone quite so well as the cradle!

Its paper rolled up in a rope like form. Its light and does not add weight but when you glass over it forms a ridge giving increased strength. You should be able to buy it from Glass stockists. Foam strips are good with epoxy but it melts with polyester.