It is very good news that you have taken the plunge.
I hope you enjoy the building as much as I am.
As to you questions re vacuum and carbon.
I will give you my persective on these points but yours may
finally vary depending on what your intended primary use.
First vacuum- the weight that you will save will depend on how
skilled you are at hand laminating.
An unskilled person will save more weight by vacuuming than a
skilled laminator. In my case I have given figures in previous
posts in this thread as to the amount of resin used to wet out the
laminate and then how much came out in the vacuum comsumeables.
From that you can work out the weight savings. With some calculations
you could probably break that down to an average per sq metre
saving and with info in the plans work out how much I would save
given my skill level.
You may save more or less but it will put you in the ballpark.
I will use my boat in coastal sailing so my primary reason for
vacuuming is strength. The bond between the foam and laminate under
vacuum is as good as can be achieved.
The other considerations when vacuuming is the added cost and the
added time. There is the cost of the vacuum consumeables vaccum film,
tacky tape, wadding and bleeder.
It may be as much as $1,000 say 1/15 the cost of the hull materials.
Then there is time.
Once you have a structure ready to laminate you can roughly treble
the time it takes. To get a good vacuum you have to prepare a surface
that the tacky tape can form a really good seal to, laminate, apply
the vacuum consumeables and film and chase any leaks. I've managed
to get a vacuum of around 25 inches of mercury on most of my sessions
which is quite a good vacuum but there is no such thing as a free lunch.
I considered using carbon instead of glass. From the plans you could
work out the weight savings.
Three things influenced my decision.
1) Cost, I did a rough calculation on he added cost of carbon and it nearly
doubled the cost of building the basic structure. If you are seriously
considering carbon get some prices and see how it comes out for you.
2) I don't like cutting and grinding carbon. I've found nothing as sharp
as fibres of cut cured carbon. Using carbon in the beams and boards
will be enough for me.
3) Resale value- I did not think if I sold the boat in years to come that
I would get the added cost of the carbon back.
This is just the way that i see it.