We put the first coat of primer/ high build filler on the hull today, which went fairly well. Although we need to play with our spray gun setup and try to get more of a "Wet coat" effect as we had a fairly dry/dusty effect coming from the gun, which took quite a long time to get a decent coat over the boat. On the next coat we might try the larger nozzle size (2.0mm) as opposed to the 1.4mm size on the current setup as well as adding more than 10% thinner to the primer.

We are planing to the spray the colour next weekend.

Hull laminating has been essentially completed, decks and side tanks are laminated in place as are all the hard points for fittings. At this point the hull weighed in at 41kg the minimum weight for the class is 51kg. This gives us 10kg for paint, filler and fittings.

I have worked out that i need 1.5L of (Waratah Red) colour paint for the hull, deck and side tanks and 0.25L for the white floor so i have ordered a bit more than this for wastage and spare paint in the event we need to do a significant repair down the track.



So far we have two three coats of "bog" (thickened epoxy resin with Q-cells) over the hull and "torture" boarded two of these coats and already the hull is look a lot nicer and fairer. Once we are happy with the shape or "fairness" of the hull we will spray a two part primer/filler to fill any left over small holes. Then we will be onto the final paint topcoats.

We have already ordered a new high modulus rig from CST and approx $1500 worth of pulleys, cleats and fittings from Ronstan. At this stage we are planing to be at the first state titles rounds in mid October in some form or another. Although there is still a lot of work to do associated with the centreboard case, vang system and fit out.

side tanks are in!

Hi all,
Finally its starting to look like a boat!Side tanks have been glued in and laminated into place. The port tank will act as a spinnaker chute, helping to keep a clean cockpit and the stb tank will be a bouancy tank.
(this is a view down the spinnaker chute from the bow)

All of the hard points have been laminated into place, which is 5mm thick fibreglass plate, with approx 4 layers of carbon over it on the floor. These will then be drilled and tapped for an M5 or M6 bolt to attach fittings.
After re-weighing the hull with the following; sides glued in, foredeck on, gantry in the boat. The hull came in at 39.5kg which isn't bad, but i doubt that we will make the 45kg lower limit for the class (hmm that 6kg's of lead would have been good!)
This is an image of me trying to work out how to mount our vang system. The blue pen lines are a radius out from the centre of the mast, while the other lines are different layouts of connecting the system. The lay-out above with the green string appeared to follow an arc from the centre of the mast the best, meaning that when we was our main out and out boom angle increased the distance between the mast and boom vang will remain the same, giving a constant boom vang tension. This whole set-up will be discussed in more detail once it has been built

Just weighted the hull.

currently at 35 kgs that includes:

• Hull
• Floor glued and laminated in
• 1 side tank
• Bulkheads
  
• bowsprit structure
• transom bar
• Gantry
• Carbon blocks for fittings (almost 0.5 kg)

The class minimum weight is 51kgs including control lines and bowsprit.

So i figure 5 kg more in glue and fibreglass, 3-4 kg more in fairing compound and primer allowing 7 kg for fittings, bolts, ropes and foot loops.

So at this stage its looking like i should be able to fetch the minimum weight with not too much hassle unless the hull requires a lot more filler than first thought or paint.

Current progress

This is the side tank under vacuum on the side tank mould. I was quite happy with how this process worked. Using only 5 supporting frames and a 3mm sheet of melamine coated MDF as the mould surface the shape held very well, even under vacuum there was no distortion or warping.
This is a roughly trimmed side tank, this will be going on the port side and will house the spinnaker to keep the cockpit neat and tidy. The mould gave a good smooth surface which should be easy to paint straight to will minimal filling and sanding.

This is the "tension member" that I have Incorporated into the hull fit out. The idea behind it is to help triangulate or form a space frame between the mast step and stay mounts to help increase the stiffness of the hull and rig, which hopefully will help to reduce fore stay sag when sailing, which may ultimately allow for a wider range of rig tensions to be used. The member only weighted 280g so hopefully the advantage will be worth the small weight penalty.


This is a quick image of the fore stay mount attached to the top of the bowsprit receiving tube. The plate is made from two layers of 2mm thick 0/90 deg woven prep reg plate, then extra layers of 0 deg fibres to deal with the tensile load and +- 45 deg fibre to resist "shear out" of the fore stay pin

This is a photo of the rear bulkhead that supports the bowsprit receiver tube. The bulkhead is glass and foam with local carbon reinforcement to help distribute the load to the hull. The joining tape for the bulkhead to hull joint is laid on the -+ 45 deg to provide good shear strength in the joint.
The floor has finally been glued into place using Q-cells and epoxy.


The centreboard case was opened up and the polystyrene foam was dug out.


This is a photo to try and show the collapse that we found in out rudder. That surface was the upward facing surface in our mould when we used to expanding epoxy foam. It looks at this stage like it was a large air pocket or void which has collapsed for some reason after it was made. Although we are uncertain why it collapsed as the carbon skin should want to stay in its moulded shape so they must be some sort of suction or residual stress present to force it to collapse, time will tell...

Also completed but i don't have any photos at this stage, the port side tank has been fitted, starboard side tank has been laminated, rudder gantry fitted and trimmed, spinnaker opening shaped, spinnaker chute has been laminated and carbon plates for fittings have been cut.

Bring you more photos shortly.
Cheers

Quick update

Above are a few images of the new side tank moulds. They were made using five 16mm MDF templates glued to backing strips then a sheet of 3mm melamine coated MDF was bent over the frames and glued down. Hopefully this set up will be able to resist the loads put on it from the vacuum bag, only one way to find out i guess. Plan is to pop one of these out this weekend.


Above is an image of us doing a rough fit / check of the foredeck and floor panels. Both of the these were pulled straight from the CAD model and fitted really well straight away. The foredeck template was also useful in highlighting how much the hull actually moved / spread out once it was removed from the jig.

This is a photo of the bowsprit receiver tube that i thought would be useful to share. Basically to fit the receiver tube a section was cut out of the bow and a simple bulkhead with a hole cut in it was made to support the back. The section that is on the stem will have a fairly substantial laminate (3-4 layers of 300gsm UNI + 1x 200gsm cloth) wrapping over it and down both sides of the bow. The bulkhead will then have a few strips of uni and some cloth to take to load to the gunwales and down lower on the sides of the hull. This area is going to have a few more little tricky bits and ideas thrown at it over the next couple of weeks so I'll keep you updated.

Floor ribs laminated in, centreboard case laminated in, bulkheads laminated in.

Next on the list:

• Fitting bowsprit snout
• Fitting floor
• and building side tank moulds

I'll through some photos up shortly

quick update of todays work:

Bulkheads glued in
Floor ribs glued in
Centreboard case glued in

Plan for tomorrow,
Laminate in place all of the above and trim/fit floor and mast step area.

mucking around with paint schemes

current thinking is red hull/deck/side tanks with white floor, carbon fibre finish on; transom bar, gantry, rudder box, foot rests. Then black gunwhale and fore deck grip. P.s. i'm also open to suggestions for paint schemes and names.

update:

Over the past week we have been a little busy. Firstly we finished making the mouldings for the dolly, took the hull off the jig, laminated the inside, began fitting internal ribs.
We made the dolly last year after undertaking a basic TIG welding course at TAFE one night a week for a semester. As our final project we made the dolly for the cherub using 60x40x3 6061-T6 aluminium and used 25x1.5mm 316 stainless steel for the axles. All up in materials i think it cost about $200 plus $40 for wheels from eBay. So to fit it to the new boat all we needed to do was make a support for the hull. Note: The reason we used such heavy section aluminium was because of the way our boat sits on our 8x4 ft box trailer.

The above image is the centreboard case as it came out of the vacuum bag as you can see it pulled into the corners quite nicely and the overall finish is pretty good. The second image is the Styrofoam beginning to be melted out with acetone, after beginning this i realised it would have been a much better idea to leave to foam in there until it was in the hull as it is quite flimsy, so i stopped. Although i did notice that acetone was able to seep from the inside to the outside of the skin even though there was 4 layers of 200gsm glass, so it looks like i will need to paint the outside with a coat of resin to help make it water tight after it is in the boat.


I thought this image was worth adding this is the size of the extra reinforcing patch i used under the mast this was 1 200gsm carbon cloth on the 0/90 degree angle to the centre line (compared the the main hull skin at -+45)

I thought this was a good image to add showing the laminate wrapping around the hull/chine. Overall i was pretty happy with how the -+45 laminate laid over the hull and continued to stay approximately at -+45 as we worked towards the bow. I guess I'll see how good that decision was when we come to trying to fair the hull.



The first image is the jig again once once the hull was removed, the second showing how it was able to flat pack and store easily (to dismantle the jig only took 15mins and a electric screw driver)

This image is of the legs of the table/jig, i thought it was worth mentioning how we levelled the jig. Because our jig design had a table with 5 legs it was important to have the leg length adjustable to account for the un-even floor of the garage and our assembly etc. So we used a "coach- screw" in the bottom of each leg allowing the height to be adjusted simply with an open ended spanner.


This is the hull as it can off the jig.


This is the hull after we laminated the inside of the hull, same lay-up as the outside as it is very important to try and keep the laminated balanced so that when the hull is loaded up it doesn't try to warp. Also the floor ribs have been trimmed and ready to glue in and the centreboard case has been roughly fitted.


These are foils after we sanded the recess on the leading edges ready for their joining tape (1x 200gsm layer at -+ 45 to the centre line so it drapes well over the corner the fibres are at the right angle to resist the shear loads at the join)

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.

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.

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.