Building Shaw 550 - 2012/2013

Hi, my name is Bryan A.V. Pang. This blog of mine will serve as a portfolio to document all my learning in building the Shaw 550, a composite boat. I would like to take this opportunity to thank my mentor, Christopher Lovegrove for the superb guidance and patience he had shown. His teaching method had been one that is relevant and practical in preparing us for the industry. He had been a good mentor, one that I am proud and grateful to have known.

A brief description of the boat; it is a 5.5m performance day sailer designed by Rob Shaw. It has an open transom, plumb bow, shallow draft, and a fore cabin. It is to be constructed of western red cedar for its hull below the chine line and sandwich foam construction everywhere else. As this is a huge construction undertaking, carried out mainly by students, overseen by our mentor, Christopher Lovegrove, there is a good chance I would miss out on undertaking certain tasks that would yield different learning experience due to segregation of responsibilities. In any case, please enjoy my learning in building the Shaw 550.

Through out the construction process, I have documented my reflection on the construction of the boat. From reflecting on mistakes made to eureka moments where all seem to tie in together. If you are interested in my reflection, it can be found here, Building reflection.

For ease of following the progress, I have decided to compile the portfolio based on components buildings combined with staged sequences, all in order to make the reading easy to follow.

Technological advancement
Setting up - General
The deck - Male frame
The hull - Female frame
Individual components
Joining the deck and the hull

Technological advancement

Recently, the level of communication or integration is fast tracked with improvement in technology. The introduction of mobile AutoCAD combined with a tablet essentially allow the onsite or offsite boatbuilder or component maker to have access to crucial information when they need it. Of course, the plan reader would need the competency to understand and interpret the lines plan and construction plan. In a broader sense, this adaptation of technology could potentially cut miscommunication and idle time should a road block occurs during construction. My personal experience with the adaptation had been a positive one. Understanding the overall plan and having access to them paints not only a holistic approach to any task, but also cultivate forward thinking skill, critical thinking, problem solving and to some extend project management skill.

The building begins....

 Setting Up

We first need a list to specify where all the station frames will sit. Grid lines would need to be drawn on the floor, all the different stations mark out, and most important of all, be accurate.

 Once the grid lines had been marked out, floor battens were then glued onto the concrete floor using hot glue. The various weight sitting on the batten serve to exert pressure while the hot glue cures.

Drawing perpendicular lines can be easily done using the 345 method or the 575 method when marking out the grids.












The frames would be aligned forward or aft of the grid lines depending on the deck line shape of the boat at the given station. Once that is aligned, a cleat pushing against the frame will be glued and screwed down into the bearer before adjustment with dumpy level takes place.

We braced the stations with temporary gunwales and a diagonal brace on to the floor. The purpose of this exercise is to afix the position of the frames according to the gridline. In another word, the topside of the frame could move out of position, it needs to be kept in correct position.  It is important to get the set up right.

The Hull 

The hull is built using female frame mold. It is to be constructed of 8mm thick strip planking using western red cedar below the chine line, and 8mm 80kg density closed cell foam for the topside. The glassing of the inside hull will utilize 240g EDB glass using the bucket and brush method (hand lamination) while the outside hull will be vacuumed bag using 400g EDB glass. In both instances, we use laminating resin ADR25 and harderner ADH.

Identifying required timber for strip planking is the first order of business. We needed measurement of the widest part, the intended width of the planking strake, the thickness of the strake, and finally the length of the strake. Once we have the list, we can then move on to apply the measurements into the standard timber stock available. The timber come in 75mm, 100mm, 150mm and 200mm for the western red cedar. The goal is to work our the linear meter of timber required and the stock size needed. We subsequently ordered 4 planks of 200 x 45 x 5800mm red cedar.

 It is crucial to consider all possibility by brainstorming or forward thinking what is to happen. In this case, we considered the 'wastage' due to timber cut turning into sawdust, student skill level - the need for extra bit of timber in case of mistake, freight cost if another delivery required, and so on.

The final thickness of the hull is meant to be 10mm in accordance with the designer's specification. We need to work backwards from there. 1mm for the inside glass, and 1mm for the outer glass, leaving 8mm for the cedar.

Note: we are trying to maximise the resources available yet at the same time conforming to the designer specification, and proper boat building practice. Eg, the cedar strakes need to be of quarter sawn, and not flat sawn! Any good boat builder will tell you that.

The two strakes in the middle is position in a way that the joints represented the center line. Two benefits of doing so, 1) the center line is inbuilt, 2) we set the stage for symmetrical working surface.

The narrower piece of strakes on the chine are so to allow bending to conform to the compound shape of the hull frame. A narrower strake is easier to twist in comparison to a wider strake.

A quick note: Forward perpendicular line is sitting on the aft face of the station frame. It is there fore crucial to ensure the strake to reach, even pass the FP line.

Another noticeable feature is the use of the clamp to hold the two end strakes in place. The primary purpose is to hold them on the SAME plane, or level, instead of having on higher or lower than the other. At the same time, the clamp can correct any tendency of the strakes to twist, while being glued down.

A useful epoxy stand to make our life easier. Strake of plank is set into the slot, ready to spread epoxy onto the side. This set up provide numerous benefits including, enable a one man operation, keeping the area tidy and improve efficiency.

There are many views and ways of doing strip planking. The intended final look and pattern determines how the strip planking is to be laid. The most difficult concept for me to grasp is estimating the tapering and fairing of the strakes from station 5 running forward to the bow.

The one learning curve that's practical and makes a lot of sense is to allow the strake to lay as it wishes without any twisting stress exerted onto it. The strakes could have been laid wider, closer to the chine lines and without stress at the aft end. This would allow for ease of strip planking, making the process much faster.

Another pointer is to ensure when joining the sides of the strakes together, the nails need to be dagged in at an angle towards the joint to ensure a tight joint, void of gap.

When tapering the strakes, to make the symmetrical and aesthetically pleasing, a few pointers to account for...
1) the colour of the strakes pieces need to be similar, a question of selection
2) the tapering need to be mirror image, it can reduce the amount of work to be done later on

The plumb bow design of the Shaw 550 demands a tight radius at the bottom. Getting the plank to clear the curvature is not easy task even for the seasoned boatbuilder. The strake not only needed to be tapered, it needed to be beveled as well on one side for the next plank to sit on.

Once the radius is cleared, the remainder of the strip planking moving upwards and outwards becomes easier.

Strip planking is well underway, getting easier the more we work on it. We gradually got faster and better at estimating the amount of epoxy required for the plank side.

In hindsight, we could have potentially cut the work time by half if there is a team working on the port and another on the starboard.

Note: Spiling for the topside is taking place as we are finishing up the strip planking process...

Strip planking the hull with western red cedar is finally completed. The last piece, known as the shutter piece required a little bit more work to get it in. It is just the nature of strip planking.

We would need to pull out all the nails before
filling any gap in the joints.

 Sanding the inside of the hull is more difficult than one could imagine. Sanding a relatively flat surface is easy. It gets harder as one progressively move forward with more curvature in the hull. Took extra care not to sand the edge of the chine piece in order to prevent rounding of the strake.

The forward end of the hull is particularly tricky as the sanding pad would not conform to the shape of the hull. Therefore, we took to planing the inside using a straight spokeshave. It is faster than sanding, but definitely require some degree of skill to do a good job.

 Once the hull is backfilled and sand or cut, it was time to seal it. We used ADR450 and ADH450 epoxy based timber sealant for this practice.

A quick note: there are 2 school of thoughts when sealing the timber. One suggests that nail holes to be backfilled before applying the timber sealant. It sounds logical but then the question of penetration rate comes into play. A backfilled nail hole with thickened epoxy will undoubtly have smear mark surrounding it. This 'smear' only seals the surface, it does not penetrate.

Once the thickened epoxy harden, it serve as a barrier preventing the timber sealant to penetrate the timber below the smear area. The other school of thought to is hold off the backfilling process, seal the timber with the sealant first, completely saturate the nail holes. Once 100% timber penetration occured and dried, then it is time to backfilled with thickened epoxy. Trouble is, the smear mark in this instance would require some sanding.... We went ahead with the first instance.

Component: Topside
Process involved: Nesting, spiling, joining, scribing, bevelling

Brief summary
The tackling of the topside occured as strip planking of the hull is near completion. A spiling plank was initially used to mark out the shape of the topside. Next came the nesting of the topside shape unto the various sheet panels of 80kg 8mm foam. Joining the panels of foam sheets were necessary via butt joint. As the topside cut was not a perfect fit on the first try, some scribing were necessary to eliminate gap at the chine line. Bevelling the foam for a perfect fit comes last by way of sanding before butt jointing the topside to the cedar plank at the chine line.

Stage: Glassing the hull interior
Materials: 240g EDB, ADR25 resin and ADH,
Process involved: Marking out, materials preparation, dry fitting, record keeping, hand lamination

Brief summary
Marking out where the lap of the glass will be is crucial before we could lay the fiberglass in situ. The fiberglass would then be cut to length, labelled and rolled onto a roller tube for ease of storage. Other materials preparation en suit, including peel ply, ADR resin and hardener, gloves, squeege, and brush. The resin would be mixed accordingly with proper record keeping of the amount used. We used the bucket and brush method to wet out the glass in situ ensuring there is no dry spot. Once wetted out, peel ply is subsequently laid on top of the glass. The nature of the ADR resin is slow curing, allowing us a maximum of 3 hours to work, subject to temperature of the workshop as well.

Component: Athwartship floors
Process involved: Vacuum bagging (in situ operation)

It is crucial to mark out the exact position of the various floors. We had to use straightedge and plumb bob measuring out from the forward perpendicular line. Again plumb bob is used to provide various points in the hull so that marking can commence. Note; it is easier to tackle this preparation stage with another person .

The discovery of paper cutter is a miracle for us boatbuilders. Previously, the task of peeling off the peel ply at the intended line required the use of cutter used upside down, nipping milimeters of peel ply at a time.... a time consuming, arduous, frustrating task.

When peeling the peel ply, it is advisable to wear safety glass, and peel the peel ply slowly to prevent breakage to the glass underneath.

One interesting consideration is the marking aspect. Initially, the points would have been made on the peel ply. Now that the peel ply is gone, so too is the marking made on the peel ply. Thinking forward, we had a tick stick that has a marker for the fore face of the floor, CL of the floor and the aft face of the floor. The tick stick approach expediate the whole remarking process.

The foam is laid on top of another held down with hot glue. The intended shape of the floor is meant to be a tophat shape, topped with carbon. Prior to the vacuum bagging process, the end of the foam would need to be tapered.

The vacuum bagging process of the floor is an interesting one. As the process is done in the hull itself, there are a few additional considerations that need to be taken into account for, including
- the location of the darts to prevent spanning, some understanding of generator line helps identify darts location
- fiberglass cannot be laid over existing peel ply.

The outcome of vacuum bagging the floor is a semi successful one. We encountered issue with leakage at the top of the topside. Air managed to seep through the glass with dry patch on the topside. Another area to be aware of is the underside of the edge of the peel ply where vac tape is placed.

I can vouch that doing all the vacuum bagging on your own is possible. It took me a day on my day off to vacuum bag the floors in the hull. That was the only instance a 1 bar vacuum was ever achieved. The trick to working on one's own is to prepare everything in advance and forward think what could go wrong or need consideration.

A manifold is useful if there are a few vacuum bagging process required. A point of interest though, there will always be exact tools with specific purpose, but that would require some capital investment. As a boat builder, one needs to justify the cost of getting them. If it is going to be a one off instance, perhaps a temporary measure is the way to go. In this case, proper valves should have been invested instead of mini clamps for the manifold.

The notion of flange on the hull is noteworthy.
If there is no flange, we would have a hard time joining the deck to the hull. Someone would need to be sent under the deck to glass tape or cove the deck to hull joint. The flange is incorporated to design out the problem. The deck in this instance can be squash bonded to the hull with thickened epoxy on the flange.

 The construction of the flange required the use of temporary jig. Some lofting of the flange section will yield crucial information on where the flange sits on the topside and hull.

Some considerations to take into account..
- bevel of the temporary jig
- shape of the temporary jig
- how to hold the temporary jig in place

Demoulding the temporary jigs with a release wedge. The flange looks adequate. It required some sanding to rough up the surface for better keying surface.

While the flange were being built in, the collision bulkhead can be installed.

 Meanwhile, the flange on the girder is being prepared.

Throughout the construction process, i noticed as the build continues, the momentum gets faster and faster. The completion of the hull allows for various components simultaneously by different individuals.

In hindsight, a delegation of tasks would expedite the construction process further.

Rubberized epoxy is apparently very expensive. It allows for a slight flex once in its cured state. This substance will be used to cove the T of the girder instead of normal thickened epoxy. A normal thickened epoxy once hard, tend to be brittle, the rubberized epoxy is not.

The readied stanchion is glued in situ. It is crucial to verify that there is no hole when gluing the stanchion.

The stanchion is installed prior to the joining of the deck simply for the reason of ease of installation.

Crucial considerations, the angle of the stanchions need to be the same, preferable the same angle as the topsides, and the stanchions need to be in alignment looking across girth.

The aft bulkhead is dry fitted by another group, slots cut out on the flange with proper marks indicating positions.

I learnt scribing to fit the bottom of the aft bulkhead is not the same as offsetting inwards. The scriber needs to be adjusted to the biggest gap, held PLUMB and scribed all around. The key is to have the scriber vertically held.

The installation of the keelson is difficult due to vac bag that is too small. I learnt there should be darts in every corner if not bigger darts. When we cracked the valve, we noted there were numerous spanning occuring. It took awhile to rub the vac bag down to improve the vacuum bagging process.

The Deck

The deck is built using make frame mold. It is to be constructed entirely of foam core with fiberglass laminate on the top and undersides. Similar to the hull, the glass for the outer skin will be 400g EDB, while the undersking is 240g EDB. Both laminates laminate will be glassed using the vacuum bagging technique. 

As per the hull frames setup, the male mold frames were set up on bearers, leveled using a dumpy level. The various station frames not only need to be level, they need to be plumb as well, adjusted using a spirit level. One interesting note to take into account is the last station's position. It sits 8mm short of 5500mm, the full length of the boat. Why? It has something to do with the transom construction and the marrying of deck and hull once they are both ready.

The angle of the cockpit side is not constant, as evidenced by the differing angles on each station frames.

It is important to recognize that the cockpit sole foam has a thickness. The foam would need to be cut to the upperside of the sole, NOT the underside of the sole. Only then can sanding or cutting take place down to the bevel required on each station.

 As part of our critical thinking, we discovered one sheet of foam sheet will not suffice to make the sole of the boat. Therefore, we had to joined a few foam together using a butt joint. The gluing process was done on the loft floor where the surface is flat. Once the panel is ready, we proceed to mark out and cut the foam.

 As previously mentioned, the sole was marked and cut to the upperside before beveling takes place. This is done through sanding of the foam using a long board.

 It took us a few go to try and get the shape exact. A long timber batten is required to draw a fair line on the station frames. Notice how the foam is sitting on the frames everyone, where beveling is required, we marked out the bevel.

Gluing the fore deck foam in situ required the aid of holding jig. We decided to make the construction easier and faster, the butt joint of the two foams will represent the center line for the boat.

 Strip planking of the cabin top is a relatively straight forward process. The main concern encountered by students is to hold the foam down against the frames. As the foam have no fiber orientation, they are easy to bend and provide no real resistance to conform the shape. Because of that properties, we could simply hold the foam down using masking tape.

 Scribing the forward end of the strip of foam is the hardest, requiring some skill to get it accurate. We marked out each of the foam to prevent any confusion when gluing up.

The strip planking on the cabin top is done from the center line moving outwards. In theory, there can be two team working on each side of the cabin top. The only downside to the whole process is the fact only a few strips can be glued in a day. Based on initial assessment, the cabin top can be fully completed in 3 days. In reality, it took more than a week.

How the side piece of foam is glued down. We needed force pushing the strip foam to the deckside, and force pushing the strip foam into the frame. Problem solving at work.

Make shift frame to hold the various strip foam in place while waiting for the epoxy to cure.

My general conclusion about the strip planking using timber and foam:
- foam strip can easily be held in place with masking tape, timber strips needed nails
- foam is relatively easy to cut and shape

The cock pit side is easily prepared using the spiling method, transferred onto the foam and cut out. Holding the foam in place while the glue dries is another different matter. Like other parts of the deck, we did not dag nails to hold the foam in situ. Because of that, we had to get creative by other means.

The carlin is the final piece to be dry fitted after the installation of deck side and the cockpit side.  It takes patience and numerous dry fitting to get the right bevel. Personally, i find the construction of the carlin to be difficult as the piece actually tapers to nothing running forward. Not only that, the bevel could be different as well running forward. On the upside, any imperfection such as gaps can be filled with extra glue.

While the glue dries for the carlin, we took the opportunity to cove the corner between the sole and the cockpit side.

The need for coving: Glass do not do well with sharp corner. Forcing the glass to conform to sharp corner would likely to break the strand of glass. Therefore, we cove the corner to allow the glass to lay around a radius.

A 50mm lap is then cut out using a laminate trimmer. The 50mm lap is inwards of the deck line of the boat. We grooved the lap for the purpose of lapping glass at a later stage. If there were no groove lap, the lapping of the glass will result in a bump on the final surface. This would mean sanding is required to get a flat surface. There is a likelihood the overlapping glass would be sanded off, an undesirable outcome.

The transom too is grooved for lapping glass. The interesting notes about the transom is that we had to create a flange that act as surface area for the vac tape to sit on. Due to some pressure to be exerted on the flange, we needed some webbing to provide stiffness to flange.

Notice how we did not cut the excess foam. We needed the extra surface to glue the flange on.

The sanding on the deck takes place before the vac bagging takes place. The goal is to achieve fair smooth surface void of bump. The general rule when it comes to sanding is recognizing that an area is high or low. Bumps at a later stage would need to be sanded risking glass strands sanded away. Low area on the other hand can always be built up with thickened epoxy that can be sanded to fair.

A strip of peel ply is glued onto the outside perimeter of the second glass panel. This is all in preparation for the vacuum bagging process. The vac bagging required a surface for the vac tape to adhere to. It can be put directly unto the foam, but the task of taking the tape off is time consuming and inefficient. Hence, come peel ply that allow us to peel it off with the vac tape on it, leaving the surface clear of vac tape.

The first vacuum bagging of the deck took close to two hours to accomplish. There were a few glitches encountered including from having a hole in the foam resulting in the absence of vacuum, resin run-off unto the flange, to having darts in the wrong place.

I found the idea of vacuum bagging is straightforward, but the implementation of it in a scale larger than a work table becomes more and more difficult.

This instance of vacuum bagging is made easier by the number of students around. Handling vac bag 5x5 meters on one's own will be a difficult task no doubt.

The vacuum bagging on the forward end of the deck is trickier than the aft end. There are two segments worth mentioning, 1) the bulkhead warants a LONG dart running cross sectional, 2) the narrowing of the deckline running forward would be result in a long dart if the vac bag is not taped down following the shape of the deck line.

The process of dismantling the station frames take place once the glassing of the top deck is finished. We need to turn the deck upside down to glass the underside of the deck. As the deck is still in quite a fragile state, we need to leave a few key stations in place to hold the deck without falling over.

Once the deck is upside down, we can make the next stage of preparation for the glassing of the underside. As usual, preparations are needed. These include..
- installation of glass plates for the transom
- peel ply base for vac tape
- sanding
- marking out

The rest of the main bulkhead is finally being glued on. The one lesson this practice taught me is that unless there are good lofting, it is wise to leave the material (in this case - the foam) larger than it need be - NOT cut to the definition.

The installation of carbon strips are more difficult as we had to cut holes in the deck sole for the carbon to get through, before sealing it off for vacuum bagging. Beside the bulkhead area, the vacuum bagging on the underside is easier overall in parts due to having more practice with vacuum bagging.

Individual Components

Components falling under this heading covered components that can be made offsite. These include but not limited to the construction of girder, aft bulkhead, center case, mast beam plate, and so on. In the boat building industry, it is common to have components for a boat made away from the boat itself.

Component: Girder
Process involved: Vacuum bagging (offsite)
Materials: ADR246 and ADH28 (Laminating resin and hardener), 260g EDB glass, peel ply, perforated  plastic, bleeder, wind break, vac bag, vac tape, vac hose, disposable brush, squeege and a moulding table.

A laminating resin and hardener is used as these have slowing curing properties allowing ample time to work using them - 3 hours subject to room temperature.

 A point of interest however is that the component laminated using the laminating resin need to be post cure by baking it in a hot box for 12 hours on a constant temperature of 60 degree Celsius.

When dealing with the laminating resin, it is common practice to keep a record of resin used for tracking purpose. These usually include resin volume, hardener volume, starting time etc. The benefit of such practice provide accurate information for any given job and allow for work time estimation.

Vacuum bagging 101: Know the stack you are dealing with. It is as follow
Top
      vac bag
      wind break
      bleeder
      perforated plastic
      peel ply
      glass
      girder
      glass
      peel ply
      perforated plastic
      bleeder
      moulding surface

The moulding surface is where the vacuum bagging process takes place. It needs to be devoid of dust or any other impurity to maintain its surface. Normally, preparing a moulding surface would require a few application of wax and PVA (poly-vinyl-alcohol) as primary and secondary release agents. A waxing schedule could be made.

Once all the stack materials are ready, it then becomes a matter of work orientation to ensue ease of working when laminating.

We wetted out the underside of girder, applying the necessary stack before turning over and continue with the top stack. Keeping the work area tidy is desirable and ideal. Keeping the moulding surface as neat and void of spilled resin is particularly important. If by chance wet resin got onto the surface, under the vac tape, there is a guarantee the vac tape will not stick to the moulding surface, resulting in air seeping in. One way of overcoming this issue is to prepare the perimeter with vac tape or masking tape, setting the boundary for which the component will sit in and extra care to be taken close to the tape.

Quick summary of the stack material:
Peel ply - the protective skin that protects the fiberglass layer from impurities
Perforated plastic - the layer that allow excess resin to bleed through
Bleeder - highly absorbable material like a tampon
Wind break - allow air and resin to easily migrate
Vac bag - enclose and act as a barrier to allow for vacuuming
Vac tape - gorilla snot that has high stick-ability to seal off any leakages

Once the stack are in place, it is time to seal off the vac bag and mount the vac hose. For ease of handling, we afixed the vac hose position with a clamp. Darts were installed as a prevention to spanning of the vac bag. The flatter the surface , the lesser the number of darts needed.

A successful vacuum bagging will have 1 bar of atmospheric pressure. We did not achieve vacuum on the first crack of the vacuum pump. Since we did not have a leak detector, we had to go around the vac tape listening for any leaking, a hissing sound.

After 12 hours under vacuum, the resin has cured sufficient for handling. To achieve 100% curing of the resin, it needs to be baked in an oven for 12 hours under 60 degree celsius.

The component is now ready to be cut using diamond saw. When cutting glass in the grinding bay, personal safety needs to be adhered. Ideally, a coverall is needed, glove, respirator, ear muff and safety glass. Based on personal experience, a full mask respirator is better than having separate pieces worn.

Most components including the girder and the aft bulkhead are glassed on the moulding surface. The centre case is however glass slightly different. We utilized what is called an envelope of vac bag, as well as a plug. The plug being the centerboard substitute.

Due to the shape of the center case slot, it is not possible to 'wrap' a one piece fiberglass cloth. Instead, strips of 400g EDB glass were cut and wrap around.

Mast beam, mast plate and rudder plates are all made of glass of varying thickness. Infusion is the method used to make these. The basic concept of infusion is to feed resin through an inlet, let it migrate through all the glass cloth, and out the vac hose under vacuum. The benefit of infusion is the tidiness of the work area.

The mast beam were cut out of a panel of glass after marking in conjunction with our lofting. Strip of carbon was then wrap around the edge of the mast beam.

Dry fitting the mast place is tricky, requiring some problem solving. I need to ensure it is a snug fit. It needed to sit plumb with the face aft face of the main bulkhead. It needed 100% gluing on the edge, void of gap. Most important of all, i need to be able to take it out!

Making the stanchion is slightly different. There was no vacuum bagging involved. A mandrel is built to house a pvc pipe. Glass would be wrapped around the pipe before putting on the peel ply. The pipe however would need to be heated up to expand via running hot water. This will eventually be reduced to tickering droplets into the pipe, in attempt to keep the pipe temperature from dropping too much. The glass cures fast due to the heated pvc pipe. Once cured, the pipe with the glass is chilled in the freezer to shrink the pipe and popping it out.

Joining the deck and the hull

Dry fitting the deck and hull was a success. There were a few concern but nothing that cannot be amended. We noticed there where visible gap in the deck line towards the bow.

The biggest issue we had is the girder sitting too high resulting in a gap between the transom and the inside of the hull. It took awhile to identify the cause of the lift.

Gluing the deck down is harder than it sounds. We had to ensure the flange with epoxy is in contact with the underside of the deck. The deck needs to be held down one way or another.

We found the transom was sitting slightly high. We resorted to using the ceiling to provide some compression on the deck itself. It works better than expected.

One major issue encountered is the forward face of the transom not squash bonded to the transom flange. We exerted forward force by clamping blocks on station 15. Notice where the foot of the clamp sits.

Holding down the deck side unto the flange using clamps and a wooden block.

Any gap between the deck side and the topside needs to be back filled. A gap or hole will not do well for a boat.

The deck is now successfully joined to the hull. We then moved on to sand the excess foam on the topside. The top of station frames represented the sheerline. It is a matter of marking a line and sand to the line. To ensure fair shape, we need but to sight down the line sheer line of the boat.

The boat is finally turned over. It is now time to fair the hull of the Shaw 550. Below are the sequential process..
1) back fill any holes or gaps in the hull and let dry
2) plane the hull
3) sand the hull

The protruding center case slot would need to be sealed on its sides. A dam is built around the center case slot before being filled with relatively runny epoxy. Once the epoxy is dry, it is time to detach the plug before cutting the excess glass of the center case slot.

 While the center case casing is addressed, others work on the installation of glass plate for the shroud on the topside of the boat.

The state of the hull is taking a fair shape. The only issue i have is the interpretation of fairness. What may seem fair to me may not be fair to another individual.

Planing the hull is much faster than sanding. Generally, planing will cut away 80% of high or unfairness. The remainder percentage falls on sanding to fairness.

In my opinion, the hull below the chine looked fair. There is still some work around the spray rail. But overall, i would consider this hull fair.

Once the hull is faired, we took the liberty of relocating the shaw 550 into the FRP bay for a coat of sealant. When the timber sealant was neing applied, we had to ensure everyone had a repirator and that the vent is functioning.

Glassing the hull comes next. The few main issues encountered.

1) implosion of the center case under vacuum, due to absence of fiberglass tape around the case and the underside of the sole
2) sticking the glass cloth onto the lap on the deck.

The construction phase is finished with the glassing of the hull.

Our Shaw 550, class of 2012/13.

With that, the CAT boat building course comes to an end. It had been a great year.

"I diligently attend workshop without fail not so that I can get good grades when attested, but to be able to say at the completion of the course 'I can build boats now'"
                              Bryan, boatbuilder