Laminating main hull part 416

The aft part of the port under wing area is laminated. It's just the middle part and the bag left on this side, postponed due to a bad bag experience lately....


Recess for the external safety compartment hatch, has to be incorporated in the last laminate on this side somehow.


Starboard under wing area is almost fair enough for lamination


I laminated the bow area last night building it up with several layers of carbon under the hybrid cover. It will be very beefy. I hope I will never know how big floating lumber it takes to break it.


At last today a teaser for the true sailing nerds: I've decided to make my own carbon wing mast in the moulds used years ago for the Formula 28 trimaran Mirage. It is kind of funny to see how all the boats on Derek's Trimaran cool blog have this kind of mast. I received some cut off's of Mirage's mast today from the designer and builder Per Ferskaug. Quite impressing to actually see the dimensions of this air foil, chord 57 cm (22") with 19 cm (7½"). The picture shows the middle part of the spreaderless mast, as seen in the video it tapers towards the ends. The challenge is to build this mast without a weight penalty, as the aerodynamic properties are superior, and the absence of spreaders a very tempting property. Carbon comes in all kinds of qualities, and ditto pricing. I'm currently investigating trough Silas Spence how we're going to do it using Toray's M46JB fibres which are kind of middle of the pack in High Modulus fibres, being ~90% stiffer and ~20% stronger than the regular commercial fibres that I use in the hull which in turn approximately doubles the properties of regular E-glass.


I'll be "out of office" for a week now, due to a work related out of town intermission. I'll probably be able to go sailing a schooner as well....

Sailing. And some more building

Staale and I sailed Frimann from Levanger to Trondheim last Sunday. Reasonably nice weather, not freezing temperatures and we managed the whole trip on one port tack, starting with a double slotting reach in light air, ending double reefed and close hauled in 20+ knots on the nose and rough chop. Best possible medicine!!! No pictures due to technical problems with the bluetooth interface, I am sorry. This was the first time we rigged a sprit (klyverbom) on Frimann, and we flew the symmetrical spinnaker from the pole. Not optimal, but still very effective in the light conditions, sailing 8 - 10 knots in Beaufort 3-4.

Yesterday I managed to laminate parts of the deck-hull transition in the bow area, and today I flipped the hull to start preparing the underwing area of the hull. It is just these areas and the bow cap left now before the hull is laminated.


Quite a bit of fairing was needed to make this area fair. Rigid sanding board with 40 grit paper shown. I am not sure how big radius I want on the edge here, maybe a bit bigger than this.


An upside down 'portrait' of the main hull

Busy month not building a boat

It has been really difficult to find time for boat building lately, a total of 8 hours I guess in October so far. This does not allow for much progress. But last week end my friend Dag (happy birthday, Dag!) and his daughter came up from Oslo to visit, and we were able to get a couple of nights in the workshop as well. The first night we laminated the starboard side and bagged it. 3 hours work, and a perfect result.


The next day we rolled the hull, Dag took a picture of the proud boat builder, and we started the cabin sides.


Routing for flush mounted Lexan windows.


Then the side was faired and we wet laminated an 'A' equivalent carbon fabric from the gunwale to cabin top. As I started struggling with the vacuum bag Dag finished the port window routing:


Still problems with the bag. A leak trough the hull, we were able to locate it quite exactly, but not able to stop it. It was outside the laminated area so we just took the vacuum we had (10% or so) and drank a few beers in stead.


The bag pulling just enough to avoid bubble trouble.


This last week have been another 60 hour working feast despite my current 20% leave, and now they want to close down our hospital as well. I need to go sailing, and will do so tomorrow. Tonight I managed to drop by in the workshop and laminate the other cabin side. I didn't even bother to try get a vacuum for this side. Thorough wet out of the foam and steady temp will make it, I hope.

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

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.

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.

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... ;-)