Rob R, Roan and I infused the 3rd 1/4 hull. It went smoothly, but not as fast as yesterday, possibly because we did not preheat the mould as it was a warm day.
Used 19 kgs/42 lbs of resin, the same as for the opposite half. ~3 of which is in the flow mesh, ~2 in the peel ply, foam and plumbing. The calculated cloth weight is ~26 kgs/57 lbs, so not far off 1:2 resin fibre ratio. It is about 20% of the total hull and decks area, so total panel weight of ~200 kgs/440 lbs. Plus 1m/40″ of foam bows, a couple of ring frames, 2 stub masts, a wall of shelves/panel stiffening and joining the 6 components. Then hatches, steps, windows and paint and it is ready to go. Some of the joins are conventional, some experimental. Hopefully they are more successful than the attempts to make the tender easier to assemble. If not, I have 2 x 7 x 12m of glass tabbing to look forward to.
Manhar and Sai turned up in the afternoon and cut the glass for bonding the hull halves together next week while I prepped the tender for the final bit of glassing, prior to a rough fair and paint.
Demoulded the 1/4 hull and it is as good as it looked. The diagonal stringers with high density polystyrene formers are excellent. The panel is plenty stiff enough. About the same weight as 600 glass either side of 12mm foam, but tougher, cheaper and easier to build and repair.
Laid up the next one with a couple of hours help from Roan. Tried a different layout for the stringers using less material and bigger angles.
Opened a new roll of Chinese vac bag material and it is much easier to use than the conventional AirTech nylon type. Less stretch allows long runs of crease free sealing. Conforms the same and is plenty strong enough to bridge gaps. It does not crease as much, so potentially reusable as a bag rather than as a mould liner. Maybe.
2 guys laying up and infusing a (near enough perfect, from a laminating point of view) 12m/40′ half hull in a day and a half is pretty good going.
I took the test rod (looks good, noticeably stiff for 2m/80″ x 12mm/0.5″ diameter) to Martin’s after post curing it under black plastic (75C/167F for a couple of hours in the sun) and had a chat with him and Doug about trusses. Both are impressed with our solutions to the fastening problems and are looking forward to testing the model. Trusses are pretty well established structures, but once you start bending and tapering them, while applying loads in multiple directions like a cargo proa beam, analysis gets tricky. The most likely failure mode is buckling of the compression struts. Making them hollow would reduce this, but increase windage and, while easy enough to make, they are difficult to attach, given my aversion to bolts. We’re looking at other solutions but they are difficult to model and analyse so the test model(s) become important.
Both Martin and Doug are now enthusiastic about a truss for the lee hull if the non truss problems can be solved.
Infused the 1/4 hull. Went well, the stringers all appear to be well bedded and we used the same amount of resin as for the slightly larger, non stringer 1st piece, so it’s probably a good one. It looks the same as the first piece which lost and regained vacuum, so maybe that one is better than we thought. Rob R figured out a clever solution to the beam stabilisation problem and Brad and Teguh made a sample rod for testing, probably next week as we will need the results to build the beams when the hull infusions are finished. One of the required tests is material compression strength. It will be interesting to see the jig which tests this accurately as it is notoriously difficult to align the loads so that the failure is not a result of buckling or uneven loading.
Roan and I laid up the 2nd 1/4 12m/40′ hull with plenty of time out to admire Rob R’s 1/5th scale beam and discuss the next steps and the Opti wing rig.
Moved the tender over and set up and glued the 12m table. Tender seat verticals bonded in. Weighed it and was surprised it is only 205 kgs, with a bit more to add and some to remove. Not too bad for a 8.4m/28′ solid fibreglass (almost, I used some old bits of Bucket List hulls to support the seats) power cat with a fair bit of tabbing where ideas and experiments did not work as expected.
Cockpit boxes are in, foredeck bulkheads started, nose piece on foredeck (Rob R), table sealed with a mixture of cabosil and red pigment (Roan). Lots of discussion about the truss beam model, electric motors and the table set up, which was far nicer than filleting in the tender cockpit lockers.
Mould bent, vertical on, aligned (Rob R) filletted and coated. Bow reinforcing on tender (Rob R) which was a bit more difficult than i thought it would be, but worked out well.
The tender has the anchor slot cut in the foredeck, the sides cut and the stringers bonded on. We moved it outside on a couple of wheelbarrow wheel skates. Almost effortless. Hope the 12m and 24m hull are equally easy! Rob R beefed up the mould supports and started on a f’glass rack while Roan did some mould sealing, then we spent an hour or so discussing the boat and how the windward hull would be built. Most enjoyable. The truss beam design is looking better with each iteration and discussion with the engineers. Rob R is making a jig this weekend so we can build a 1/5th model for testing.
Boat building has been a bit slow for the last couple of weeks and Harryproa enquiries have gone through the roof so I have been spending my non building time responding rather than updating.Rob R has got the rudders ready to trim and assemble. Took a bit longer than expected as I managed to convince myself that moving the edge spacers negated the need to build left and right hand pairs. Not so, idiot. Consequently, we had some reworking to do. This was made a lot easier by the leak detector my brother in law built us using some car parts and a glasses case. Works a treat, leaks sound like loud static and you can home in to a fingernail sized area. It noticably reduces the discussion (and daft ideas, mostly mine) about where the leaks are and why they can’t be found. The tender work has been mostly boat building. Cutting, filletting and glassing the areas where join ideas did not work as planned. Educational, but tedious, although as each step is completed, the boat gets stiffer and better looking so not entirely unpleasant. It still looks like a box, but it is getting some curvy bits. Spent a lot of time thinking about stiffening the panels. The process usually starts with ‘should have used foam and to hell with the expense, fragility and expertise required’, but after several cups of tea and discussions, we have solutions to most of it. Top hat stringers under the deck and centre cockpit are pretty good, but need more than glue and glass for the ends so we use tow through the deck to attach them. Fore and aft boxes for the anchor rode and fuel/battery/engine spares divide the other 2 cockpits into smaller panels and a trough down the foredeck stiffens it up and will allow anchoring without needing to leave the cockpit, which will be difficult once the solar panels are installed. Unfortunately, this will not be until after the Queensland Govt decides to reopen it’s borders. Doug the engineer is one of those rare engineers who can converse with laymen and accept ideas which aren’t his and/or aren’t in the text books. This was accelerated when Rob R built a couple of 700mm long x 100mm x 100mm trusses from 6mm timber. Amazingly stiff, light and strong. Doug is working on optimising the trusses for the beams which are considerably lighter, easier to build and much cheaper than the conventional box beams. Rob R will start building a 1/5th scale this week for testing. Analysis of trusses for the lee hull and masts are next on the agenda. The work on the inflatable sail continues, but it is getting more complex as the inlets need valves. With our new found ability to make non linear rods, Roan has printed the jig and is making an Optimist sized wing rig when he is not repairing vacuum pumps. The quest for student volunteers has resulted in 10 enthusiastic engineering students starting next week, all going well. They came and had a look and seem a pretty bright bunch. It will be interesting to see how my time/people/logistics skills cope. 3 weeks after I announced it happening tomorrow, the tender and table swap places this week and we start to put together the 12m table for the windward hull panels. With the knowledge and experience from the tender experiments, this should be a fun job.
Arrived at the shed before Rob D today and got strait into prepping for the rudder half layup. When Rob arrived we planned the rudder layup process and decided what to do about the tender hatches. The hatches will be left for now, but will go on the inboard hull sides at a later time. It was decided they are not needed till after launching. They won’t be water tight just covered as they will be vertical. Hatches on the deck are in the way of the seating and would need to be flush and water tight.
The rudder layup was to be part hand layup and part infusion as Rob was concerned the resin would not get between and under the carbon. In the end It worked out well despite being an experimental procedure. The bag was fitted to one side of the mould, the carbon and glass under it were hand wet out while the rest was left dry and a dry glass layer placed on top of the carbon. The Bag was then closed, evacuated and the whole layup infused.
It was all hands on deck with Rob wetting out, Roan placing the carbon strips and myself mixing resin and trying to remember to take photos. Previously Rob and Roan had been busy trimming and preparing the tender decks for cross stringers. Unfortunately they could not infuse the stringers as the long awaited resin will not arrive till tomorrow. There was just enough for the rudder infusion.
August 2020 #14
Installed the other half of the floor and the innwhales for the deck to glue to. If I had had a bit more confidence in my measuring and infusion abilities, these would have been slots, making adding the deck quicker and lighter. Demoulded the truss diagonals. They looks like a winner which is good as I had spent the weekend thinking about truss beams, truss masts, truss wishbone booms and truss hulls. Rob R working on the rudder mould, Roan making tender stringers.
Bow floor and gunwhales are bonded in. Bonded the test truss diagonals to the horizontals. Looks good. A bit fiddly, but not too messy. The floppy flax hull sids are no more. Halving the panel size has made a big difference, bonding on the deck should make it acceptable. Rob perfecting the rudder mould.
Tender deck fitted. I should have made the slot wider, but once the technique is sorted, it goes in pretty easily.
August 2020 #13
Starting to take shape quickly now. The tender is eight and a half meters long. It is just the boat to go ashore with the ferry itself will be 24 meters long. So we literally have a big job ahead of us.
August 2020 #12
Due to circumstances beyond Rob’s control there was no work Monday. Howeveryesterday and today was business as usual. I have managed to prepare andinfuse the 3rd tender bulkhead. Rob cut me loose and let me do it on my ownwhile he and Roan busied themselves on the deck mold, glass layout andbagging. That will be tomorrow’s excitement infusing the first deck half asit’s a pretty complicated looking layout. Again the cautious decision was made to only do one half at a time so there’ll be a second infusion needed, which will probably be next week. Helping to speed up the cutting and layingout process this week is our brand new electric scissors. I think Rob willfind it’s some of the best money he has ever spent – they’re fantastic!
August 2020 #11
Demoulded the tender bulkhead and glued it together. Looks good, but a lot of work. Laid up the second one. Infused the first tender floor, which went well.
Laid up the second tender floor and infused the second bulkhead. Went well so we infused the floor as well. Vacuum was lousy, so we added a second, small pump. Bang, down it went. However, as the infusion progressed, the flow rate slowed alarmingly, including missing an area where there was obviously a leak in the table which probably would have shown up if we had a gauge instead of doing a pull up test. We swapped pumps with the bulkhead, which helped, but not much. At about 6 pm, the flow stopped, presumably because the resin had started to gel in the feed line, so I broke my promise not to fiddle and inserted two more feed tubes. These worked reasonably well, so I plugged in a third, which hardly worked at all. Almost certainly because the fiddling had caused leaks. The resin gelling is caused by the occasionally excessive heating we expose it to to get it up to the recommended >30C in less than 20C ambient. It would be less hassle, but more money to buy winter hardener. I turned the heaters off and left at 9 pm with about 10% not wet out.
Next day, dry area had halved so I removed the bag, diffusion cloth and peel ply and applied resin with a brush and hot air gun. Wet out 5 layers of 400 gsm and the stripes in the peel ply against the mould became visible. Later in the day, we removed it and there was no visible line so presumably it is OK.
July 2020 #10
Prepped the table for the tender floor, Rob R laid up the foamless bulkhead and Roan did some more tests, including a successful Soric one and a less successful tow in pvc one. He also serviced the vac pumps, which now work much better (more suck) and 3D printed an adaptor for the pump inlet. Handy guys to have around.
Rob R infused the bulkhead, looks good. Used a bit more resin (2 kgs vs 1.5) than expected, but there are a lot of places for it to hide. Will see tomorrow. The 1st half of the tender floor is ready to go when the pump is available. There are 4 components that require a wide table (ww hull sides, tender floor and deck). Decided it is less work to build them in halves and join them rather than extend the table. Plus the joins are all in the floppiest part so will act as stringers. Another test piece seeing whether perforated plastic between 2 layers of 6 x 400 uni would work. It does. We will probably lay up both deck halves in one shot, possibly also the ww hull halves. Volunteer insurance is apparently sorted, should have a few more workers soon. Weighed one of the tender hull shells: 50 kgs/110lbs. Not bad, on course for <150 kgs all up.
July 2020 #9
Roan and I joined the other tender hull. Easier than the first one. Had an idea for a foamless bulkhead, should be ready to infuse soon.
Tender information: LOA is 8.4m/28′, hull beam 650mm/26″, BOA 2m/6’8″. Reasoning behind the hull shapes: It needs to carry a ton or so, fit between the beams and have room for solar panels (some of which will be removable or on a raisable roof). The hulls have no rocker as they will always be trimmed bow up. They are double ended to avoid submerged transons under high payloads for drag minimisation. It is also easy to build, but adding rocker to the mould would not be difficult.
Previous pics and reports are on http://harryproa.com/?p=3788 and https://www.facebook.com/Harryproa/?ref=page_internal
Explanatory notes at http://harryproa.com/?p=2561
July 2020 #8
Glued the hull together. Remarkably quick and easy. Did some more test pieces, some successfully, some not so much. Prepped the other half hull for joining. Had a meeting with the other partners to discuss samples for testing and meet the engineer who will be doing the FEA stress analysis and laminate details for the beams, mast and hulls. Ordered some samples of an interesting ‘eco resin’ for testing.
July 2020 #7
Infused. Best one so far. Used 16.8 kgs of resin with double the weight of laminate (only one layer of flax, the rest uni glass). Rob R and Roan controlling the measuring and the temperature meant I could spend time watching and worrying. But not fiddling, which often leads to problems. Fun part was using the temperature to control the resin flow. No heater on the part near the vac outlet meant the resin front got to the end of the spiral, then evenly to the end of the laminate. The three of us should be able to produce a 9m/30’ panel every two days with time to spare for joining components next week.
July 2020 #6
Beam sample infused (see pics) although far from perfect due to the inlet port losing contact with the spiral and an unexpected (as always) resin raceway developing. Will try a second infusion next week. Glass tow infuses easier than carbon. Laid out the third half hull. Female joins on both edges which made it finicky. Rob R made a cool set of scales which saves 500 bucks and made weighing much easier. “No glove” measuring and mixing (ie, no contact with the epoxy) is now reality, the resin bench is near(er) pristine and we can look at further fine tuning of the layout, heating and minimising materials.
July 2020 #5
Too cold last night for the resin to cure so spent today repairing a couple of small infusion misses, moving heaters around and making a mould for the beam sample. Infused it just before we left.
Spent the morning driving to the docks to get the material (1 tonne/ton) from China. Unloaded it solo, should sleep well tonight! Have now got the glass tow for the test piece for the beams and the carbon extrusion for the mast sample and the rudders which should stop us getting bored. Got the bag on and infused hull half #2. I had repaired a chip in the melamine with brown tape (stupid!) which leaked, but apart from being frustrating and slowing things down, it did not make any noticable difference. Used shade cloth and perf plastic and a single feed. Took 3 hours, resin usage numbers tomorrow. Looks good apart from a dry spot on the edges next to where the heater was, presumably too hot, too quick. Easy fix with some resin and a clamped on flat piece. Sorted out the resin measuring/mixing so it is now glove free. Need scales which weigh more than 1 kg at a time before we start on the serious bits.
Rigged some strings from the roof and lifted half hull #1 off the mould and got it outside. Took a bit of effort and a little grinding to get the spacers out due to inadequate taping, but nothing major. Also a small resin puddle where the bag was not applied evenly. Might come out with the peel ply, but grinding is more likely. The secondary infusions look good, a faint line on the peel ply on the outside. Finished cutting the materials for half #2 and got them laid out apart from the bag.
July 2020 #4
Repaired the dry spots by running a length of spiral across them and infusing. Not perfect but not far off. Photos show the extra length of spiral. Heated it, cut the materials for the next half hull then demoulded it. The plastic mould liner worked well. I should have plastic taped the mould edge but nothing a sharp chisel didn’t fix. The vertical looks good, I can’t lift it solo to see the horizontal surface.
Infused the first half of the first tender hull. A few dry bits from vacuum close outs which were not a problem on the samples where the resin front spread across the laminate. Solution is a strip of infusion medium down the middle of the mould and one feed line instead of two.
Could have been fixed during the infusion by poking a vacuum source into the dry area, sucking in resin, removing the source and taping the hole. Uncharacteristically I decided not to risk the whole job for a couple of dry spots. Should be easy enough to fix them tomorrow, but it would be a lot better if it wasn’t required. The pictures were taken before the resin stopped flowing, the end result was not quite as bad as it looks. The other glitch was the not extending the feed close enough to the vac outlet. The samples infused 300mm/12” across the stack but today only 100mm. Not sure why but suspect the resin cured quicker than expected due to some pretty aggressive heating.
Resin used 15.8 kgs, 400g in the lines and buckets. Maybe 2.4 kgs in the spiral peel ply and medium leaving 13 kgs in 8 kgs of flax. I might have to work harder on getting the laminate tight in the corner of the mould.
June 2020 #3
Flax samples were impressive.Thicker than the glass so stiffer and heavier as more resin was required. However the economics work as the flax is gratis. Flax is easier to work with in some ways, does not itch and is more stable as it is tightly woven. Hard work to cut will be good when the electric scissors arrive Hand laid a sample bulkhead as the pump was in use. Pretty rough but the method has merit. Will test it in the morning along with a sample join Cut the flax for the tender and prepared the mould. Infusion next.
June 2020 #2
Assembled the mould for the tender (one side and half the bottom). Prepped an infusion of some flax and glass. To compare. No vac pump so infusion tomorrow. Flax rudder mould was not fully cured so put it outside in the sun. Sat it on a couple of rocks which indented it. Heated the affected area, put some weight on it and the bumps disappeared. As near as I can see it is about the same stiffness as equivalent glass weight but used more resin.
Infused 2 stacks of flax and 2of epoxy. Couple of dramas caused by using black poly pipe instead of clear soft pipe. Not only can’t you see the resin but when you clamp it the poly pipe splits. Plus it was 12mm and my biggest drill here is 10mm so the resin inlets were not as robust as they could be. Nothing a heap of tacky tape couldn’t fix. Pics show the infusion rate which is near enough identical for flax and glass but the flax uses more resin.
At 20C 300mm/12” is about the limit of resin travel with this resin. So 2 x spirals will work for the tender half hull.
Day off tomorrow, infusing samples for join testing on Monday might get the first half infused by the end of the week.
June 2020 #1
Cleaned out the shed. Found 2 rolls of 400 gsm woven flax that we can borrow for the tender subject to some tests.