Friday, July 30, 2010

Its go time....

Outside of hull was laminated last week, dolly and supporting cradle has been built and finished yesterday. The hull is ready to remove from the jig and flip over this Saturday. Then we will be able to laminate the inside on Sunday.

From there on in it is all hands on deck almost 6 weeks to the sailing season (looks like it might be a few weeks late). The two images above are some of the printed out templates of all the cockpit and interior. This is what I'm hoping will help drastically reduce our build time and where having a 3D CAD model of the boat should come into its own.

After the hull is laminated on the inside the internal structure will go into the boat in stages in the night time after uni during the next two weeks. Once the components are positioned and glued in place we will come back later and laminate / vacuum bag them in. I'll update with more photos after we flip the hull.

Tuesday, July 20, 2010

idea for laminating the centrecase

This is my idea for laminating the centrecase into the boat hull.

Firstly when we build the cradle, we make sure the area under the centrecase is well supported. Then mark out the area and grind away the foam so that we are left with the outside skin only in the centrecase area. Then the centrecase is trim, aligned and positioned. This is then bogged into place using a strong filler such as a glue powder or some sort of fibre filler and a small radius is made between the outside edge of the case and the hull skin.

Once this has cured and been neatened, the first laminate is done and cured. After this a foam wedge or filler piece is bogged into place using a light filler such as Q-cells and the second laminate is done over the top to tie everything in.

The reason for this double laminate process is because it allows you to distribute the load from the centreboard case into both the top and bottom skins and providing a large area to spread this load on the case its self.

Also note that in a loaded case such as a centreboard the hull exit is under twice the load of the centreboard head/floor exit so the hull exit needs to be particularly strong and the floor exit can be made a little lighter.

On the floor exit, I intend to glue a foam strip around the case to the height of the underside of the falsefloor so that it can just drop straight on top / around the case and be glued in place, then reinforce the opening from the topside of the floor.

Sunday, July 18, 2010

Above image is an assembly of the cad models i have been using to size and design components. The layout is not 100% of what i intend to use, but it has been extremely helpful in locating important points and dimensions. It has also allowed me to investigate the size and shape of the side tanks so that i can ensure it meets the class rules as well as provides enough space in the side tank to fit the spinnaker chute.

This is the centreboard case i intend to use, it allows the centreboard to have 200mm of movement fore and aft so that I can tune the centreboard position to the new rig and rig position. The adjustability comes from using different cover plates, both of the these plates on top and bottom are held together with a threaded rod. The cover plates are made custom for each centreboard position that is needed.

Above is an image of the cover plate in place, this top surface will be flush with the top skin on the false floor.

This is the centreboard case in the vacuum bag. It was constructed by shaping a piece of extruded polystyrene foam called "ISOBOARD", which is normally used for insulation. This was then laminated over with 4 layers of 200gsm glass cloth on the -+ 45 deg so that the cloth would pull into the tight corners. It was decided that 4 layers should ensure that the case is water tight.

Saturday, July 17, 2010

Hull laminated.... almost

Finally started laminating the outside of the hull today and halfway through ran out of carbon... looks like we used a lot more that we thought making the previous components for the boat. On the plus side, having the cloth on the -+ 45 degree allowed the cloth to draped over the chines quite easily. Also using scrapers/spatulas to wet out worked extremely well even on the curved surface of the hull. The peel ply was used to help soak up any excess resin and help prepare the laminate for secondary bonding of paint and fairing compound.

Looks like the next opportunity to pick up some cloth and finish the hull will be Thursday so hopefully not to much time will be lost. I will be able to pull the profiles for the cradle of the CAD model tomorrow so we can build the cradle while the hull cures. We will also be able to construct the centreboard case, member for the space frame, spinnaker chute and side tank mould in parallel to laminating the rest of the hull.

Wednesday, July 14, 2010

hull shell ready for laminating

Finally have finished putting foam onto the jig. We have faired in any rough areas and are ready to laminate the outside of the hull. The outside laminate will be 1x layer of 200gsm plain weave carbon cloth laid in a +- 45 degree axis with respect to the boats centre line. The main reason is to help increase the torsional stiffness of the hull and secondly the cloth will drape easier over the chines and sharp corners of the hull. A reinforcing layer will be placed over this to help spread take the load from the mast step and centre case area. This will be approximately diamond shaped and the fibre orientation will be 0/90 degrees to the hulls centre line. This laminate will be mirrored in the inside of the hull.

here are some photos of the hull ready for laminating:

Transom of the hull, about 10mm of curvature so almost flat.
Bow area certainly seems sharp and fine, although the intersection between the chine and bow is lower than the Matthew's hull. This means that the bow might not actually be as fine as i was hoping, I'll need to see two hulls together to find out how much finer we have made it.

A view from the back of the boat, its difficult to get a decent shot in the garage of the true shape of the boat so I'm looking forward to when we can take it off the jig and move it around a bit.

The current plan is to laminate the outside of the hull on the weekend then begin constructing the cradle next week.

We will be just using a simple wet-layup technique on the outside of the hull using plastic spatulas/scrapers as much as possible then applying a fine peel ply to help absorb excess resin and give a surface that's almost ready for secondary bonding.

Friday, July 2, 2010

Tiller looks fairly good, perhaps a little heavy at 370grams without clear coat paint, but it is very stiff due to the large cross section used at the box. So i should be pretty safe from breaking it if i try to support a bit of my weight on it.

Hopefully will be glueing the finaly pieces of foam on the hull tomorrow so we can get it ready to laminate during the week.