Swallow Boats have recently been experiementing with a more modern construction method that allows light weight mouldings to be created from conventional moulds. Here Dougie Hanton describes in more detail how he Infusion moulded our Storm 17 design:

Over the last 6 months or so I have been introducing a new moulding technique at Swallow Boats which promises reduced weight and increased strength. Until now we have been offering  our hulls in either plywood or GRP construction - both have their advantages and cater in different ways to our customers needs.

The Vacuum Infusion Process (VIP) is a technique that uses vacuum pressure to drive resin (in this case I used epoxy) into a laminate composed of glass fibre and a foam core material. These materials are laid dry into the mould before a large plastic sheet is laid down on top and sealed round the edges for form an airtight bag. A vacuum pump is then used to suck out all the air and create uniform pressure on the laminate. Once a complete vacuum is achieved, taps are opened and resin is literally sucked into the laminate via carefully placed tubing.

This process offers a number of advantages over a wet lay up. Significantly it uses only enough resin to wet out the glass, creating the ideal glass/resin ratio, so forming the  lightest and strongest structure possible with minimum resin waste.

For this project I wanted to combine the best qualities of the two construction methods we currently offer, giving in effect, the best of both worlds

The hull itself is of vacuum infused laminate construction, with timber keel bilge runners and stem posts offering the simple beauty of a seamless round bilge, which I shall finish with a slightly matted 2 pack paint to give a more traditional look

The interior will be of tough and durable CNC cut epoxy coated plywood combined with timber detailing, which I think contributes to a lighter classic look, instantly distinguishable from the run of the mill mouldings. Offering the additional advantage that custom one off’s and differing rigs can be offered to the individual requirements of the customer.

Key to the development of the VIP at Swallow  Boats was  the  assistance of Dave Johnson, technical advisor to Wessex resins (west system) who gave freely hours of his time offering us a great combination of technical knowledge, experience and enthusiasm.

After running numerous test samples and laminate combinations the day finally came to design the lay up for the first moulding.  I chose the Storm 17 design for the prototype mould, she is one of my personal favourites, combining beauty in a form that I find very pleasurable and rewarding to sail. I also think that she would most benefit  from the rig/ interior combinations available with the new build system.

Dave Johnson laying in the first of two outer layers of biaxial glass

Next the divinycell core

Vacuum line with resin brakes. The resin brake provides a channel for the vacuum to pass through but slows down the passage of the resin when it arrives at the top of the mould. Therefore allowing any slow areas of the resin front to catch up with the faster ones

More glass on top pf the divinycell, then peel ply

Resin feed line with flow media

vac bag going on

Performing a vacuum drop test to establish the integrity of the bag which has to be 100 percent. This has to be done in a quiet workshop so as to listen out for leaks, so I came in on a Sunday

All was well with only small leak

Life can be complicated! Here is all the resin feed lines in place along the centre of the hull, the second set of lines are a contingency plan for if the resin fails to feed in fast enough

Resin bucket, catch pot (pressure cooker) and vac pump

Sanding back the first top coat of paint, gunwale, stem, keels and bilge runner already in place

epoxy coated ply interior going in. here you can also see the core, there are two layers of 450gsm biax glass on top of that!

core foam glassed in underneath the seat tops to stiffen them

Trial fitting the decks to the king plank

All warped up in cling film to keep glue of the nice paint and woodwork

Sampson post and bulkhead doublers

Grey epoxy coating sealed off areas

Decks seat tops and coaming fitted