Archive for October 2014
Seven keel floors ready for cleaning and dressing.
Fibreglass cheaper by the rolls
The last two days since clamping up the seventh floor frame have been spent buying glass cloth for reinforcing the top of the frames and in cutting out and routering the edges of the 100 mm ply doublers. Buying the glass from Nuplex was the easy task and by buying by the roll I have enough for the hull outside and inside. As well I have purchased the unidirectional glass for the keel floor tops and the first layer on the skin under the keel floor area. The more difficult task was buying a route table and finding a suitable router for it. Eventually I adapted an old Ryobi router to the Ozito router table by drilling the Ozito base plate to suit the Ryobi and that has worked fine. The shopping time has eaten into boat building time so this afternoon I moved into production mode. By nightfall I had routered all the ply doublers and ground all the surplus epoxy off seven frames.
Yes I am quick to write up our victories and slow to comment on our failures and last night was a last place on handicap.
Travel commitments and illness have taken their toll on our crew numbers so we sailed with our old North Genoa which is easy to skirt but short on area and shape. The longer the race went the lighter the breeze and the more we needed the extra power of our big black genoa.
As well as the sail selection we did not get a good run of the wind shifts nor a free passage through the black fleet from behind or the green fleet from ahead. Add to this the fact that the antifouling is getting to the end of its useful life and there is hope that we can get back on our game.
There were some bright spots for the day. Joe Walsh had changed out our genoa halyard pulley for one that turns freely and I managed to install a new shower pump in the bathroom on Passion. Today I picked up a replacement Starboard navigation light cover and by next week all the outstanding jobs on Passion bar the antifouling will be completed.
The post race raft up at GFS was excellent as always and the conditions perfect for a late night motor to the mooring at Woolwich and a quiet row home.
Seven curves tangent to the constant V bottom section which define the keel frames shape
The last keel frame is glued up on the garage floor. It will sit half way between D and E frames and is in line with the chain plates. It is the forward most station that has a radius or 800 mm to the outside of the hull and by gluing it up on a lofted set of blocks the design hull shape should be maintained.
To show the family of curves I highlighted the lines scribed on the floor for the photo.
The longest keel frame was laminated on the garage floor today. This is the aft most frame and has no keel bolts through it but it does share grounding loads. Grounding loads are those extreme forces generated when you are flying along at eight knots and hit an immovable reef. The rear frame structure has to be strong enough to stop the back of the keel breaking the backbone. There are three frames sharing these grounding loads and they are all tied together fore and aft with a keelson structure and with the sides of the engine bearers. As a bonus there is a big frame that forms the front of the galley and engine housing and that is right above the aft end of the keel. By my calculations if we hit a reef all that will happen is the bow will dive down while the stern rises up and the water will act as a shock absorber. There are two more frame so do but these are the two shortest ones at the front of the keel so just two more days work to finish all seven frames.
The longest keel frame that will support the engine bearers.
After three weeks away and last weeks “chicken out” it was time to give Passion some of the care she deserves. The day was spent cleaning the teak decking and cockpit and washing out the fridge. Two fire extinguishers were replaced with new ones and the chart table contents were sorted and old sailing instructions confined to the rubbish bin. The diesel tank was topped up with an extra 10 litres and two trips were made to the Woolwich ferry wharf to collect water for cleaning and topping up the tanks.
As for the racing we were short handed with crew commitments elsewhere. In fact with just Frank and Ron to support Elaine and me we had more fire extinguishers on board than crew members. In consideration of the small crew I hoisted the North tri radial genoa as it is the easiest to skirt. That was a good move as the breeze freshened considerably at the start of the race and any more sail area would have been a problem.
Our best move of the evening was to tack wide of the Birchgrove shore and hook into a lift which brought us up near the front of the fleet. We were ahead of Worlds Apart when a green fleet starboard tacker decided he needed to put us about more than he needed to tack for the turning mark at Goat Island. This unexpected move caught us completely off guard as we had to tack to Starboard with no time to uncleat the genoa. We were stuck in this hove to position for quite a while and saw Worlds Apart and the new Dehler 38 go bye.
Considering the small crew we were pleased with the results. We all got a good work out and apart from a minor bruise we seemed to all come through the event unscathed.
Next week Frank is away but hopefully Kath and Kevin and Martin will be back on board.
I have just glued up the third keel frame on the floor jig as the first and second frames produced this way are a good fit to the stringers. Because the frame is glued up square to the jig and the gap between the stringers tapers a taper has to be planed or filed onto the edge of the frame for a perfect fit. The taper is negligible near the keel where the maximum strength is required and the manufacture of the frames on the floor is most convenient.
Clamping blocks screwed to the particle board floor ready for clamping the third keel floor
Normal transmission will resume now that we have returned from a three week break in France including sailing in the Laser Masters World Championships. The venue at Hyeres on the Mediterranean was a delightful place to sail and also observe the end of seasons antics at the local marina. An aggressive looking Black Pepper Code 1 was lifted up for the winter break. She had a nice carbon bow prodder that could be rotated up when required and that is food for thought. The other activity was the repairs to a J 109 which had run aground and damaged the glass at the front and rear of the keel.
Back home while recovering from jet lag I have glued up the first of the floor frames that will support the keel. The frames have been increased 10 mm to 80 mm width for extra factors of safety and to allow for larger keel bolts for the 200 mm deeper keel we will fit. Because there is a large span between frames D and F where the 44mm stringers are unsupported I have lofted up the frame profile on the floor and glued up the the frame in a jig rather than in situ. It is more pleasant working on the floor and gluing down hand and the accurately constructed frame will secure the stringers in the designed location.
By the time you deduct the depth of plywood plus 44 mm stringers plus the depth of the frame the inside radius of the frame at the ends is around 710 mm depending on the amount of taper in the floor. This is a very tight bend for eight layers of meranti that is tapered from 3mm at the tip to 6 mm at the centre. It is right on the limit of fracture of the meranti so all saw marks and any stress concentration points have to be planed smooth to avoid the timber cracking.
I am in two minds about the rest of the floors. Once the floor at frame E is secured in place I will see what stringer deflection I get using the build in situ method but I am quite content to loft up the balance of the frames since the floor rise and radius are constant and the only variable is the distance to the tangent stringer which can be measured off the hull. It really is that simple.
Didi 40Cr keel floor being clamped up in a floor jig
The starters on duty at GFS
Not really chicken as we love a bit of wind on board Passion but the delay in the flight from Paris via Saigon used up all the time and energy we would have needed to sail last night. We did make it to the yacht club to see the start of the racing and stay for the BBQ.
The Vice Commodore wins the Green Fleet start
The J35 Soundtrack wins the Black start well