Vacuum Glass

I believe FENN are producing vacuum glass boats, the presumed advantage being they are much lighter than a traditional glass lay-up technique. As there is much less resin used, I wonder if there is a cost to be paid in terms of strength? Are these boats as durable as the normal glass boats? I'm trying to choose between a vacuum glass boat Elite SL and a carbon boat. The former is much cheaper and would avoid the downside of the fragility of the carbon boat to minor bumps.

Google 'difference between vacuum infusing and vacuum bagging'.

Hi Gary,
KNYSNA RACING have a construction option which is Glass cloth + core + epoxy resin + vacuum.
I guess the option you are referring too, is similar.

Regular glass boats are normally made using polyster resin which is cheaper and heavier, with no vacuum.

OK, thanks guys. Now that I get the difference between vacuum bagging and infusing, the question still remains as to how strong the resulting boat is. Does the fact that there is less resin used mean that it it is more fragile because it is lighter or is the epoxy resin stronger than the polyester?

The best strength to weight is with as high a fibre to resin ratio as possible.
Extra resin just makes it heavier.

Infusing generally uses less resin than bagging as the material is compressed by vacuum before the resin is introduced.

Full kevlar boats are usually bagged as they have no flow material in the layup, the kevlar core material is already wet, the bagging just compresses it all together to form a single composite.

Carbon can be either, but the lightest are usually bagged and made with fibre that has been pre-impregged with resin. (usually at a very high and well controlled ratio.)

This is because they don't require the extra cores for strength, they are strong enough with just the carbon, so any flow material just adds weight that is not required.

Infusing offers other advantages, as it is laid up dry and then infused, the others are laid up either pre wet or wet as they are laid and you are then on the clock to finish before it all sets.

Epoxy resin is generally stronger than others, but requires cooking in ovens.
Epoxy resins may also require epoxy gelcoats as per Epic's construction.

There are many versions, Kevlar weave may be laid up with a flow core and infused, but it doesn't make best use of the materials strong points.
Carbon may also be infused but suffers the same fate.

Most infused fibreglass boats will have carbon or similar reinforcing around the cockpit area.

Just keep googling and you will soon get a feel for it.

Some of the best sites are the material manufacturers.

'Soric' is a popular infusion material and a great place to start you search.
It is a combined infusion material and bulking core.
It adds thickness which makes things stiffer at the same time as using very little resin due to it's honeycomb construction.
That's the paterning you can see on most boats as the core prints through, unless they have used a print blocker layer.

Just keep pumping in high tech lightweight composite type terms into google and take the journey.
You will be glad you did.

It really is quite simple to work out exactly how each manufacturer has made their boat.

Eventually you will find out why pre-impreg carbon is the obvious choice for super light boats and then wonder what the new kids on the block at Vadjer have done to create their super light Kevlar with a little bit of carbon boat.

I'd give you a whole heap of links, but I seem to have not imported them into my new laptop and my desktop has died.

But you will soon find the big players in the composite world, it didn't take me long.

Look here for a good starting point to learn about composites.