Just a quick update here after unwrapping the peel ply cover this morning. The longitudinal carbon filaments came out very straight up and down. There’s a bit of sanding and fairing to do in spots where the layers overlapped, but we won’t go try to hide the new hoop ‘ribs’ from the final finish.
Forget about losing weight – we just spent two full days adding about 50 pounds to the boat mast. Yesterday’s work took four people five hours to spiral wrap the 2″ wide carbon fiber twice down the full mast length. Today was another six hour session to add four layers of longitudinal fiber over yesterday’s perpendicular wraps. Both days needed numerous morning setup hours to get ready.
We needed to protect the bolt holes and diamond wire terminals from epoxy and fabric. Charlie made wood inserts covered in plastic tape and we bought nylon bolts to protect the bolt hole threads.
The Tides Marine sail track however had over 100 small threaded holes and it seemed unrealistic to protect those. So we templated with heavy masking tape and will be sure to re tap those clips an inch or more away from the original holes.
With the prep done, Charlie, Griffin and Colin gloved up and took positions. In the video we have Colin and Charlie on epoxy brushing, Greg laying down carbon, and Griff rotating the mast.
hoop spiral wrap time lapse
All of it was intense work – getting the epoxy density right, keeping the proper spiral and controlling the awkward mast roll while the other three yelled “slow down, dammit” or worse. The shop looks like a battlefield but with victory:
Today I started out solo in the shop and struggled to figure out applying the 50′ long carbon pieces straight and pulled tight. Then it dawned that the roll needed to shuttle up and down the mast for its 12 trips (4 layers X 3 ten inch wide strips for the 30″ circumference). Here’s the Workmate tool on a movers dolly and some risers clamped on.
We did not pre-measure allotments of epoxy but I was watching our usage all afternoon and was happy to record 2+ gallons used (20 lbs) for 600′ of carbon weighing 23 pounds. Yesterday used a bit under 20lbs of materials, so Keith’s calculations of adding 55-60lbs total of mass look to have been spot on. Yea!
Next up will be some spot reinforcements around metal connection areas, and reattaching the spreaders. Then we’ll finally have the custom carbon mast built just for this boat’s specifications. That’ll feel good at sea.
6 hours on Sunday and 4 Monday with a big sander finally got the best of the two-part LPU paint on the mast. That is a very tough, durable paint for one’s boat.
The six inch orbital sander was using a 40 grit Bosch disk for every 5-6′ of the mast on the first side. About 5 hours in the flooring contractor neighbor stopped by and insisted we try his Bora green disks. The commercial stuff used to strip floors – wow, it only took four of those disks for 3/4 of the mast! Definitely a case for having the right tool for the job. We had to be careful of not chewing in to the carbon laminate – just get the paint!
Back to interior woodworking while the mast awaits materials….
That’s a big number – the “righting moment” of this F36 design. The leeward float and beams have all that upward water bouyancy pressure opposing the mast and sails that are trying to drive the float in to the water. Add in some high speed sailing and pounding through waves, and we get many tons of force compressing down through the nice new carbon fiber mast. This month we turned attention to getting the sailing rig finished, beginning with confirming all the specifications. Our mast was built for a Shuttleworth 35′ cat; he’s a designer who calls for very tall rigs and minimized weight. Calculations on that boat’s design show about a 70k lbs righting moment, which is in line with the measurements of our mast, including it’s 175 lb weight. Basically, we need to bulk this thing up to a new fighting weight.
Pardon the details here as we thoroughly document this project to assist with the refitting process…
Bulking up means we’re adding more structural material to the mast and increasing it’s compressive load capability to bring it in line with that big righting moment limit. Carbon and epoxy will be applied to the outside, so the mast must first be stripped back to a bare pole. It’s more than a little heartbreaking to cut in to this beautifully finished piece. Here we are at the start, with only the Tides sail track off (but the Tides clips still there)
Step 1 is lowering the gooseneck to bring the boom down to about a foot over the windshield and hardtop. Unbolt the gooseneck receiver and use it to form a new putty base in the correct spot.
Next is taking careful measurements of parts that will go back over the new work.
Jeanne’s sailing partner Leslie worked all day stripping down the mast, including over 100 sail track screws. But she respectfully declined the painful job of taking a saw to the spreader roots. They had been bonded on very well, but succumbed to the Fein multimaster. There is a stainless steel structural rod at both sets of spreaders, with the ends bolted thru the mast wall and the nuts entombed in the hollow spreader bodies.
We built a simple spindle rack system so the spar will rotate during the work, and finished the day sorting out and securing new messenger lines inside the mast for the five halyards. The mast is ready for a session of sanding away all the lovely paint this weekend.
A big thank you here to Stephen Marcoe, Jim Antrim, Guy Stevens and Keith Burrage for insisting we review the mast specs between the two boats. Keith and Ted VanDuesen came up with a smart work plan to increase compressive strength and upsize the wall stiffness characteristics. We’ll build the hoop strength via two tight-spiral wraps of 5oz uni. Start the first one clockwise, using 2″ wide fabric, just less than 90 degrees off the centerline. The second wrap goes the other way, forming a shallow X pattern along the entire spar. After this hoop work we’ll bulk up with 4 layers of 6oz uni, laid straight up the mast for the entire length. This will all be hand layup work, and not vacuum bagging as we want specific manual control on keeping the uni perfectly straight along the spar. Bagging runs the risk of introducing warp or wiggle to the fibers.
The folks at Soller Composites are weaving us 2″ wide rolls of 5oz T700 aerospace grade Hexcel carbon uni. to handle the hoop spiral. The mast is about 30″ around; six wraps per foot X 50′ tall X 2 trips = 1,500 feet of carbon fiber. At about $0.40/ft
The longitudinal layers are coming on 10.4″ wide rolls of 6oz IM7 (822ksi) carbon uni. 50′ X 3 strips of 10″ to get around the 30″ mast X 4 layers = 600′. Soller has 300′ rolls at $1.29/ft.
We’ll stick with our high grade Applied Poleramics epoxy, confident that these good materials will make a superior finished mast tailored right to the boat’s engineered specs.
Stay tuned for updates on paint stripping then the new laminations. Also we’ll try to get some glam shots of the cabin woodworking – it’s looking great now in the final polyurethane phase.
sorry about that, folks
This should do it:
You gotta love friends with forklifts. Thank you Mark at the Airless Repair Center next door! He lifted two boat hulls for us today. Spotters were Charlie and Dean forward, with Colin and Griffin managing the sterns. Mrs. Carter the Co-owner did a great job with the camera. Here goes:
The smartest thing we did today was decide before lifting that the forklift would be stationary. No nudging the lifted boat and causing any sway; the truck and trailer had to line up under the boat. That was easy with such a long wheelbase.
Hours of good prep placing the posts on the trailer and figuring out Rick’s lifting straps led to only a couple of minutes needed for each lift. Watch the first one here:
After the video we pulled the truck forward, moved the second hull to the cement pad and the forklift to the other side. All good.
Notice that first the floats were truck-strapped to their trollies. Then the lifting straps went around the hulls only, and upon lifting the hulls brought their strapped trollies with them. Lifting straps around only the hulls created a much safer pull with no wracking stresses on the wood trollies.
And we’re down. The four truck straps then got moved to travel around the trailer frame, and more strapping to tie the two floats together against any side to side forces.
No drama today, but kind of stressful for the boat builder :). It was a big relief to take this shot before heading to dinner:
And being an opportunist, I finagled the big crew for 20 more minutes to get the mast down from the rafters to ground level. For those of you who’ve been to the shop, you know what a shoehorn that was! Yes, the rotator pin just fits inside the small entry door with the masthead jammed in to the far diagonal corner. Phew. Mast modifications start in the morning. Stay tuned.