Sunday, June 3, 2018

Sportfisherman 26 - Over She Goes

The last of the hull sanding on Kevin Agee's 26ft sportfisherman was completed last week and epoxy barrier coat applied on the bottom, then she was ready to join the right-way-up rest of the world. See the video link at the end of this post for a time-lapse video of the turn-over.
Sanding and bottom barrier coat done, ready to go.
The turning was to be done with chain blocks hanging from a pair of 2x6x12ft planks bolted together, with 2x6 spacers between them, the planks braced by straps tying them to anchor bolts in the floor.

Previous boats of my own that I have turned over (34, 36 & 38ft) were all outdoors on earth surfaces and did not have turning frames around them. These differences changed how we had to accomplish the turning of this smaller boat on a smooth concrete slab and in rectangular protective frames.

We did it in two stages, with some rethinking and adjustment of equipment between the two stages. The rectangular frames meant that we needed to turn the hull 90 degrees, reposition equipment, then turn another 90 degrees. With my previous turns we could do it all in one extended process, lifting with lines attached to bulkheads adjacent to one sheer clamp and keep them there, simply lifting that side until the balance point, then lowering it slowly with those same lines and attachments. The hull had to be walked sidewards during the process, to always keep it close to the lifting gantry and it ended up rotated 180 degrees and back in the same place that it started.
Turning the hull of Didi 38 "Black Cat". This was done in one continuous turn from upside-down to upright.
Adding the frames around the hull creates pivot points at the corners of the frames and means that the boat must stop at 90 degrees and 180 degrees. We still needed to walk the boat sidewards during both stages and I had cropped the corners of the frames at 45 degree to help the frames to slide on the concrete slab during these movements. We had some issues with the frames sliding more than expected on the concrete and had to add precautions to control the sliding. In retrospect, it would have been better not to crop the corners, to leave hard 90 degree corners to grab onto the concrete rather than slide.

The boat dropped a few inches at the end of the first stage when the frames slid on the concrete. No harm done because the frames and padding did their protective work. But it warned us that sliding could be an even bigger problem in the second stage.
End of the first stage, time to change the lift point and reassess.
Looking at the boat on its side I realised that we weren't going to get this done with one chain block. The chain block already in use would be needed to control the last part of the turn. But, with the frames holding it very stable at 90 degrees, it was not going to continue the rotation without first being lifted at the other sheer clamp. So, we hunted down another chain block and rearranged the post staying before continuing. Mindful of the sliding problem of the frames on the concrete, we added two ropes tied to the frame and led through secure points against the wall, then under the boat to the safe side, where helpers could pull without risk of the boat falling on top of them. We also sourced two large tyres to serve as cushions under the frames if gravity did decide to take over control of proceedings.

The rest of the turn was done by lifting with one chain block until the balance point was reached, then easing out with the other chain block to lower the boat, interspersed with walking it back toward the lifting post before continuing.

Kevin was very relieved to get his baby safely grounded and stable again. The equipment was all removed then we all helped Kevin ad Michelle to celebrate this milestone in the project, with snacks and suitable beverages.
Job done, time to party.
Today Kevin and Michelle have removed the last of the temporary framing and finally got to see the hull without obstructions.
Temporary framing removed, we see her clearly for the first time.
Interior view from the engine bracket.

This design is still on the drawing board and not yet on our pricelist. To see our designs, go to our main website or our mobile website.


Tuesday, May 29, 2018

End of the Sportfisherman Fairing

Kevin has been finding muscles in places that didn't have muscles before. Longboard sanding large surfaces tends to have that effect. But it is a process that must be gone through if the boat is to have a really nice standard of finish. Any shortcuts at this stage of the build will show in the final finish and take even more work to improve later.

I described the general process of filling/sanding/fairing/sanding in my previous sportfisherman blog post. Now, to round off the process, Kevin sprayed on three coats of high build epoxy for the last sanding operation. This layer is much harder than the sprayed fairing layers, so much tougher to sand. Before sanding he sprayed on a guide coat composed of denatured alcohol with food colouring mixed into it. This is sprayed on in a thin film that leaves a very thin coating of colour after the alcohol has evaporated off. Longboarding this surface removes the colour on the high spots and leaves it in the low spots of any texture on the surface. Continuing to sand until the last of the colour has gone ensures that there is no orange peel or other texture left to detract from the gloss finish coats that will follow later.
The blue in this photo is the guide coat of food colouring and denatured alcohol that was sprayed on to assist sanding.
With sanding nearly finished, the hull is showing a good standard of fairness and finish to form a smooth foundation for the high gloss finish coats.
While Kevin was developing his muscles I was stripping out the temporary frames and formwork from inside the hull, items that are no longer needed to support the hull. This is to reduce weight for when the hull is turned over.

The next step was to start building the frames around the hull that will protect it and provide support while the boat is turned 180 degrees. These frames are at permanent frames 3.5 and 7, which spread the hull weight evenly and also are of similar width, allowing two similar frames to be built. The first parts added were the bottom frames, bolted to the frame bases, stiffening them considerably. With those in place the hull was raised with a trolley jack and blocked a few inches clear of the building stocks. Then the stocks were taken apart and much of the timber reused to build the turning frames. Once the stocks were out of the way we jacked the hull again, removed the blocks and lowered the hull to stand on the frames, resting on the floor.
Turning frames built around the hull, with carpet padding between the frames and hull. The diagonal braces needed to stabilise the frames must still be added.
With the temporary frames removed, the structure of the hull is more easily seen.
Work on sanding the hull, applying barrier coat to the bottom and completion of the turning frames is continuing, in preparation for turning the hull this weekend.

This design is not yet on our website, I am still drawing it. To see our other designs, go to our main website or our mobile website.

Wednesday, May 16, 2018

Fairing the Sportfisherman

Since my last post about Kevin Agee's 26ft sportfisherman project he has completed the glassing of the planing strakes and transom, after which the hull was ready for fairing to start. The fairing system chosen is from Alexseal Yacht Coatings.
Alexseal products for primers and fairing.
First to go onto the hull was 3 coats of high-build primer applied by roller. This formed the white base onto which the fairing/sanding layers were built up. It also gives a visual warning that sanding must not go any further into the coatings, instead more thickness must be built up to fill low spots before sanding can continue.

Next came a sprayed tan-coloured fairing coat that is sanded with longboards, removing high spots and revealing low spots that are missed by the sanding boards. The low spots are filled with a grey troweled putty, followed by more longboarding. Then the sequence of fairing coat, sanding, putty and sanding is repeated as many times as necessary until the hull is totally fair.

Sanding each time until the white primer is just starting to show on the original high spots ensures that there is not unnecessary build-up of fairing material on the hull. This is when the first fairing step showed its value. That first step was sanding out the bulk of unfairness from the raw wood strip surface before glassing the hull rather than adding filler to the low areas then glassing over them. Omitting that step would have increased the amount of fairing material on the hull, with resulting increase in weight.
This photo shows the bow after the first sprayed fairing coat. The white showing on the hull bottom is high-build primer. The edges of the fibreglass tapes on the bow show as ridges, even after feathering by sanding ahead of applying the high-build primer. The trowelled filler will be used in such areas to build them up flush.
Camo boat, good for duck hunting. After 2 or 3 cycles of sand/spray/sand/fill/sand the hull fairing is almost done. The white is high-build primer, the tan is spray fairing and the grey is trowelled filler.
Next will be a final layer of spray filler ahead of preparations for turning the hull over in coming weeks.

This design is not yet on our website. To see our range of designs, go to our main website or our mobile website.