Naval cadet boats

Construction of Jewell began in May 2014.

Turning Hull

September 14, 2014tony o'connor

Undercoating completed so it's finally time to turn her over. I began by making a frame to roll the hull in, the pieces below are cut to fit close to the hull and with equal radius, they will be on the far side away from the lifting tackle.

The two radiused frames in position, they are left clear of the hull, I used wooden wedges with padding between the frames and hull.

On the other side the frames are left square, the two sides are connected across the keel with a piece of 4x2, the frames are bolted to the building frames under the boat. Then each ring frame is bolted to a lenght of steel tube seen at the base with an eyebolt to take the lifting strap. Finally lenghts of wood are fixed between both ringframes to prevent them from splaying.

The next step is to lift the hull far enough to dismantle the building jig, the bolts connecting the bulkheads to the building frames are removed except on the two frames holding the ring frames.

Building jig dismantled and removed.

Before lifting the hull straps are passed under the steel tubes and over the hull just in case there is any movement, the hull is taken off the plastic boxes that held her clear of the jig and lowered to the ground, then the lift begins.

Balance point, when I lifted the hull to this point the weight of the keel started to roll the hull over, the rope in front of my legs is taken around the leg of my (fixed) workbench and then up to the lifting tackle preventing the hull from rolling further, the next part of the turn is controlled with this rope , by easing the rope the hull continues to roll to the right, this was quite a nerve wracking operation as there was a lot of strain on the rope, without a turn around the leg of the bench I could not have controlled the operation. It is interesting to note how far over the hull could roll and still self right from looking at this picture, of course a finished boat would have the weight of roof, deck, and spars which would affect the centre of gravity but this would be counter acted by the bouyancy of the decks and cabin so it is difficult to quantify exactly but I feel sure that the righting moment from a complete knockdown would be considerable.

When the hull is over far enough the boat is lowered with the lifting gear.

Finally we are back down and I can relax.

Frames removed and I get my first look at the hull.

Finishing hull.

September 09, 2014tony o'connor

After a brief hiatus to deal with other work I was able to get back to jewell and begin finishing the hull.

The first job was to make and fit the false stem . In the plans Francois advises to laminate this over the ply stem before it is fitted to the building frame, but at the time this didn't fit with my work schedule so I drew around the stem to get it's shape and then used this drawing to make a small jig. Then I could laminate the stem when I had time.

The false stem was laminated in two parts, the inner 5 layers are laminated then I drilled a hole for a shackle to use for launching, this hole will have a 12mm pipe inserted later for the shackle, then I let in a strip of brass into the outer layer to reinforce the hole, the two outer holes in the front are for a couple of screws that will help to secure this strip, then before I laminated the outer laminates I added a couple of layers of unidirectional carbon fibre to the stem at that point to further strenghten the area, this is the black line visible outside the hole.

With the stem fitted the next job is painting and fairing the hull, the paint being used here is a two part high build paint which I apply with a roller, the garboard sole and stem wre heavily glassed and will need a lot of fairing and filling . The plan is to get the hull fair and smooth with the high build, then undercoat, and then turn the hull over for fitting out, the final coats will be applied then.

Planking cont.

July 28, 2014tony o'connor

With the garboards fitted and glassed, the rest of the planks are fitted in the usual manner.

Plank no.2 fitted, the wooden blocks sticking out from the frames are for the plank to rest on while fitting.

Planking continues with each plank sealed and sanded on the inside and each of the scarfs glassed on the inside also.

Fitting fourth plank, the wooden clamp helps to hold the edges together, small screws are also used.

Monday 28th. 4th planks on both sides fitted. Hopefully if I don't have too many distractions for the rest of the week I will be able to get the final planks on by the end of the month.

Final plank, Thursday 31st.

Side view showing wooden plank clamps and supports for the plank.

Now that the final plank is fitted the next job is to fill screw holes, fair planks, fit outer stem, fllet the plank edges to the adjoining plank and then start to undercoat the hull. The plan is to prime and undercoat the hull , then turn the hull over and do the fitting out, the final coat will be applied when the fitout is complete.

Planking 2, garboards.

July 13, 2014tony o'connor

The garboards have a lot of twist forward, and are substantially wider than all the other planks.

I decided to fit them in stages, fitting the forward panel first, and glueing the middle and aft panel together on the bench to attach later.

Forward panels being fitted, a couple of screws with washers attach the planks to the stem in their correct position, the wooden  blocks on the frames hold the planks in place at an angle to avoid twisting the planks while screwing to the stem. — Forward panels being fitted, a couple of screws with washers attach the planks to the stem in their correct position, the wooden blocks on the frames hold the planks in place at an angle to avoid twisting the planks while screwing to the stem.

Planks fixed down in place without the aft ends attached. I also used some screws in the frames to hold the planks in position.

The sole and garboard are attached stitch and  glue style, this is the froward panel being glued in, I used copper wire from a local electrical shop to hold the panels together as well as the clamps and screws. — The sole and garboard are attached stitch and glue style, this is the froward panel being glued in, I used copper wire from a local electrical shop to hold the panels together as well as the clamps and screws.

I forgot to bevel the forward ends before fitting, here is the middle and aft panels already glued together, being bevelled, It is much easier to bevel on the bench than on the boat.

Dry fitting the forward end to the rest of the plank.

The plans call for the sole-garboard to be glassed after planking is completed, but I decided to glass them at this stage as they are more accessible now, this is why I haven't fitted the side shelves yet too.

After the planks are glued in, the joint between them is glassed with a double bias tape, I also glassed the keel sides at the same time, here we are preparing to glass the bottom, the green tape is on  the areas not to be glassed. — After the planks are glued in, the joint between them is glassed with a double bias tape, I also glassed the keel sides at the same time, here we are preparing to glass the bottom, the green tape is on the areas not to be glassed.

!st layer is a 300gram double bias cloth.

First layer wetted out, now the next layer.

Finally the cloth is covered with peelply and a couple of hours later when the resin is at the "green" stage the cloth is trimmed back to its final size.

Planking the hull 1, keel and sole.

July 05, 2014tony o'connor

It is my goal to have this hull planked by the end of July.

Since the planking is already cut on the cnc machine this shouldn't be too difficult except that before I can plank the hull I have to sheath the sole and garboard with two layers of glass cloth...and before I can do that I have to finish the keel.

Fitting sole

The sole is made from two pieces joined just forward of the centerboard case, the elongated slots forward of the joint are for the keel itself, It slots nicely over the centreboard case, I cut a v-groove all around the cutout to allow plenty of glue… — The sole is made from two pieces joined just forward of the centerboard case, the elongated slots forward of the joint are for the keel itself, It slots nicely over the centreboard case, I cut a v-groove all around the cutout to allow plenty of glue around the joint.

Fitting ply doublers either side of the case, these will increase the width allowing room for required amount of ballast and also beef up the case side where the pivot pin will be.

Next is the keel

The keel sides are clamped to the centreboard case and also located with small mortices into slots cut into the sloe. Each end has a "stem" a bevelled piece of wood that the sides are screwed to. The dimensions are in the plans. This piece is t… — The keel sides are clamped to the centreboard case and also located with small mortices into slots cut into the sloe.
Each end has a "stem" a bevelled piece of wood that the sides are screwed to. The dimensions are in the plans. This piece is the first part of the building process that required any shaping with hand tools.

Glueing the keel in place with a small fillet on both sides, a larger fillet will be made later

View from aft and above showing hollow ends, the aft end is filled with high density foam the forward end with 120 kg of lead.

The keel base is solid timber, a pattern for which is in each kit, I haven't cut the sheets with the pattern  in just yet so I just laid the wood in place and drew around it. The glue line in the picture is because I used some old Jarrah I had … — The keel base is solid timber, a pattern for which is in each kit, I haven't cut the sheets with the pattern in just yet so I just laid the wood in place and drew around it. The glue line in the picture is because I used some old Jarrah I had , If you are goung to use Jarrah on any boat then the keel is the place for it because it is very hard and heavy. I don't mind it being glued from two pieces as it will be well sheathed after.

The outside also has "stems" whose dimensions are provided in the plans and which require hand shaping.

Almost finished. Now the ends and base are removed to fit ballast and foam .

The plans call for 120 kg of lead to be inserted into the forward end of the keel, I have several bars of lead of different sizes which I cut and planed to size.

this piece for the front of the keel box

I used a reciprocating saw to cut blocks, and also an electric planer for final shaping

Lead shavings from the plane, these are used to pack around the ballast later, and any leftovers are melted down into a new bar.

As more lead is fitted I use epoxy with glue powder mixed with lead shavings to fill the gaps

As the keel fills I used clamps to prevent the keel from splaying as I pack the shavings and epoxy in

I also need to finish the keel base.

The cutout for the centreboard was finished with a flush cutter in the router, but this will mean that when I epoxy the base the insides will be a bit thinner than the case and will be prone to wear.Therefore I need to make the cutout a little bigger. First I use a radiusing bit in the router but one which rebates the radius a little,

Slot as it was  after being routed flush with inside of centreboard case. — Slot as it was after being routed flush with inside of centreboard case.

Then the plank is turned over and flush cut again with the bearing resting on the edge of the radius, leaving a slot approximately 1mm larger all round and a radius so I can lay sheathing cloth into the edge.

Centreboard and transom.

July 05, 2014tony o'connor

The transom is made from two pieces of 9mm ply, with mortices for frames cut into the inner sheet, these are slightly different sizes but when glued together with their top edges flush they assume the bevel required for the planking.

Both faces to be glued are sealed first, then thickened epoxy is spread on one face and they are clamped together, I used a few small screws to prevent them sliding around while the glue set, also I glued them in the morning so I could keep an eye on the mortices and make sure to clean out any glue that squeezed into them or else they would have been completely blocked with thickened epoxy,