Monday, September 28, 2009

Evaluation and preparations

When the bag was removed, this laminate was revealed. Seems like a very good result. And the hull feels very stiff. I'm happy.

I turned the hull over. This was done single handed with little effort. The hull is still very light.

A couple of hours with the longboard later. Note the rebate for fabric overlap. I have tried to feather the hybrid along the keel line with moderate success. No wonder they use aramid (Kevlar®) for helmets and bullet proof wests as fairing this stuff is harder than fighting wind mills. In the background, by the broom, a nice pile of Divinycell debris.

Aft ship

Under water hull shape

Wednesday, September 23, 2009

Finally a few hours left for boatbuilding

It has been busy with a baby, a 6 year old school starter and extended working hours as well as finishing the rebuild of the house etc, but today, with the very competent help from Staale, and definitely useful in the handling of 7 m pieces of fabric, the lower port hull was laminated. I rebated and sanded the foam shortly after my latest post, but it has not been possible to find time for this lamination until this afternoon (after working 34 hours since Monday). This is the sanded hull with preparations also made for the vacuum bag visible above the sanded field and along the keel line:

We first wetted out the foam surface thoroughly, using 40% of the fabric weight for this area. I was very keen on making this lamination successful regardless of being able to pull a decent vacuum or not. Then the first fabric layer was applied, the "B" carbon equivalent. Here Staale is making sure everything is well wetted out from the initially applied batch of epoxy (using Svapox 110 epoxy/GL hardener):

Then the hybrid fabric, making the combined carbon weight "A" equivalent and adding 160 g/m² of aramid for wear resistance, was applied and additional epoxy spread to make sure the aramid was thoroughly but not excessively wetted out. Then the peel ply and Staale had to leave for kindergarten pick-up. I went on with the perforated release film, the bleeder and the bag. I was able to pull approx -0,95 Bar in a short time.
I have read from several people that one should not use this amount of vacuum as the laminate gets "dry" but I strongly disagree. The dry laminate does not come from a good vacuum but either from poor wet-out or the intrusion of air leading to evacuation of epoxy. What about autoclave? They use several bars and do indeed get good quality laminates. Here the laminate is exposed to approx 950 kg pressure/m²:

This amount of pressure leads to compression of the fibres and the initially rather dry looking hand lay out is actually proven to be excessively wetted out as excessive epoxy is squeezed trough the peel-ply, trough the small perforations of the release film and captured in the bleeder in a quite evenly distributed pattern as this picture shows:

The heater and the vacuum pump is running and I expect a near perfect laminate to be exposed tomorrow.

Saturday, September 12, 2009

Turning the hull

The hull was turned over and supported by custom supports to present the lower part of the hull in a good working height. The black line marks the position of the rebate for overlap, 975mm from keel centreline. I will use the same fabrics here as on deck. The last part of the hull will be carbon only. Hopefully I will be able to start fairing and preparing tomorrow.

Friday, September 11, 2009

Deck laminated

After sanding the deck surface and a thorough vacuum I made up a batch of epoxy/microballoons and filled in all the obvious lows like along the UD in the rebates. There is a rebate on each side where the fabric ends, no rebate in the mid line as there are several installations here. The overlaps are made staggered instead.

I made the front deck without bagging, simply because it was a pain to figure out where to attach the bag, and remembering the leaking bag on the aft deck also made it tempting to have a shot at hand lay up again. The result was very good, no signs of voids and a good resin/fiber ratio.
The bag attachment was even a bigger issue here so I had another go with the hand lay up. First I wet out the foam generously, using aproximately the same amount of resin as the fiber weight. A paint roller is used to work the resin down in the foam surface. When the fibres are then applied, it will wet out perfectly with only light rolling over and some time to soak.

Last coaming layer laid wet in the deck laminate. Making sure to overlap down the bulkhead with the deck laminate.

Then the starboard side was applied the same way with carbon before the final wear and crash resistant aramid/carbon hybrid was put on and worked down in the wet carbon. Some more resin had to be applied at this stage to fully wet out the fabric. Then it was all peel plied and worked with a rubber squeege. It still looked perfect with no voids/bubbles after 8 hours of curing.

I found the designed window shape to create a rather agressive look on the boat. As this is, like all Farrier designs, a comfortable, safe cruiser, and one that can also be fast, but the performance is only achieved by efficiency, not excessive power (I hope good craftmanship can be added as well), I'd like the boat to look like that and not like an agressive racer. I had help from a local artist to scetch up a few alternative window shapes, and have tried out several cardboard windows. This is very close to what I will end up with. The window will be in two parts.

One more note on the cruiser/racer thing: Although if I wanted a racer I would not build a Farrier design, this boat will mostly be used for racing and sport sailing, but it will also be suited for cruising as long as one use ones head and reefs as required for safety and comfort. Additionally, all the sails you can get are usually recuired during summer as the wind is very weak most of the time like 2-6 kt, where it is usually ~30 kt or more if it is not.

Edit as an answer to Dag's comment. The Farrier window design is very clear on some of the pictures of Kermit - the little green racing machine and here is a sketch of my design, although not exactly like this as the testing showed that some small adjustments were to be made. Yes, they are critical, that's why I want to change them... ;-)

Wednesday, September 09, 2009

Starting deck lamination

I have made a little progress. First layer of carbon was applied to the main hatch coaming. This made the construction rigid enough to work the foam into the right shape and ready for the second layer.
This picture also shows a cardboard daggerboard and the HD foam inserts I made for a self tacking jib traveller. The problem with this idea was that I would get quite a slot between the jib and main due to the limitations the daggerboard made with my initial design with the traveller integrated in the deck. My friend Silas Spence came up with the idea of a hinged jib traveller and I have it all worked out in my head (and in a few sketches) now. The track will be mounted on a contoured traveller, and this will be attached to the deck trough two twin carbon "ears" sticking up trough the deck (just lateral to the mast rotation control) and a 3/8" pin trough these and a short tube under the traveller. This way I will be able to fill the front triangle and with the traveller tilted up I will be able to raise the daggerboard. The whole construction could be removed in a minute, leaving only the "ears" on deck, should that be desired.

Even more of the main hatch coaming laminated, and some more UD reinforcement rebated in the foam.

First bit of daggerboard case to deck laminations:

And the front deck. Unfortunately, the pulpit was not finished in time to control the attachment points, I guess the Harley guys will have to visit and weld in my workshop then (I found a small malalignment in the pulpit drawings compared to my hull and made the mechanics aware of that). The front deck hatch flange is now laminated in and the hatch is sitting there while curing to make sure it will fit:

Tuesday, September 01, 2009

Slowly entering building mode again

I have been able to put in a couple of hours in the workshop again. I am hoping to be able to finish the outer skin and then move the workshop home to make smaller parts during the winter. We will see.

I continued on the main hatch coamings, now ready for lamination. This will probably stiffen the deck considerably.

I also glued on the deck hatch flange and cut the deck.

I am using the "Roger-method" with HD epoxy filler in the fastener position