It’s a nice feeling to have finished the work on the frames. Now the boat building is finally making visible progress. Centerline and waterline are marked on all frames. This way I can mount the frames exactly on the jig with the laser level. It is impossible to do this work alone. Luckily I got helping hands from my kids.
I double checked the measure / spacing of the frames and compare the dimensions with the plan. Don’t make any mistake at this step. I also add some reinforcements to the jig.
See the green marking lines of the laser level.
It takes effort to drill holes / screws in the frames for attaching them to the jig. If possible i fixed the frames to the jig with perforated metal tape.
At the same time when I organized the timber for the jig, I bought 6 meter long planks of siberian larch. This fine grained wood is often used in boat building due to its water resistance and stability.
My VW Transporter with the 6 meter planks spruce / fir for the jig and siberian larch for the stringers.
I worked out the long planks in the same way as the timber for the frames. See my Blog for further details: https://minisailer.ch/?p=183
I have to cut the siberian larch boards of 6 meter lengthwise into the oversized width of 4x 35mm, 4x 55mm and 2x 75mm rods.
Festool plunge saw with long guide rails.
With the Metabo thicknesser they were planed to 22mm height and the exact sizes of 30, 50 and 70mm width of the stringers.
After planing all stringers i gave them a smooth finish with the orbital sander and rounding all edges with the router.
It was a long day at the workshop carrying 6 meter long rods from here to there, floor exercises and jumping back and forth on the planing machine. Boat building means sometimes a day long of full body workout.
All frames are made of douglas fir planked with okoume plywood. It was a long way finishing the frames. I decided against buying a CNC kit and made all the frames by hand from scratch. Before I was able to build the frames many jobs has to be done. Workshop organization, finding and buying the right materials / tools. Learning carpentry and epoxy-glueing skills etc. You can find many articles for this preparation in my blog.
Some information about cutting the douglas fir boards for the frames build is here: https://minisailer.ch/?p=183
More details about preparing the plywood gusstes to glue the joints of the frames you`ll find here https://minisailer.ch/?p=189
The construction of the frames is very simple, so that you can build them with little effort. All frame parts can be assembled from straight slats. Only the deck beams are curved and therefore have to be joined using a special technique. I glued the curved upper beams of the frames S, C, D and D’ together from fine 10 mm slats on a template according to the deck curve. Thanks to my colleagues Etienne (CG #88) and Christian (CG #103) i was able to copy the curves of the deck beams while visting their workshops.
Deck beam template.
Douglas fir strips fixed on the template before epoxy glueing.
All corners of the frames where filled with Styrodur. I made filets with a epoxy-putty-micro ballons mixture. Finally, I covered all parts that are inside the hull with 2 layers of epoxy and sanded them again to prepare the paint job later. This helps reducing the demanding sanding work later inside the boat hull.
I have already coated the outside of Frame S, which faces to the cockpit, with a glass fiber layer of 600g / m2. This work is much easier when the frame is lying down than when it is mounted in the hull. Also the cutouts for the storage compartment underneath the cockpit bunks are done.
Frame S astern.
Frame S bow side.
One note for builders working with the CNC kit. You may do the lower spar of Frame S a little longer so that the glued joint to the hull floor is more precise. As you can see in the picture below (picture was taken at Christians CG #103 workshop) this part in the CNC kit is too short and there will be a gap to the bottom planking of the hull. Maybe because of the 22 degree angulation of Frame S and not having included the bevel the CNC data set is here a bit incorrect?
This is my Frame S. I made the lower bar a few centimeters longer so the bottom of this Frame S fits better to the bottom of my hull.
The transom is a highly stressed part and has to carry a lot of equipment / fittings for example pushpit, solarpanels, outboard motor bracket, boarding ladder, windvane, series drogue attachments etc. I installed reinforcements where the backstay and daggerboard plates are mounted. I go for the optional design to put the liferaft on the inside of transom. I didn’t coat the outside of the transom and the inside to the cockpit with epoxy as it will be later coated with fiberglass anyway. I have already drilled the holes for the daggerboard plates and filled them with epoxy again to protect the mounting holes wooden construction from moisture.
Buying oak wood is a real challenge. I’ve called some lumber dealers but the offer is very rare. If they have it in stock, they sell it only to professional carpenters. So I had to think about alternatives.
The wood in the do-it-yourself stores is very poor quality. I picked out the best pieces and wanted to glue the 26mm boards together as suggested in Piotr’s blog if you can’t find a suitable size. With god’s will I passed coincidentally a barrel maker’s workshop with many oak planks in stock. Luckily the boss was there and we explored his workshop for the right pieces. There where some oak beams leftovers. I took 5 of them and load them in my VW Transporter.
The difficulty was to plan the slightly curved beams flat when you don`t have a surface planer. So I have to come up with other techniques. I aligned the raw planks on a slide for the thicknesser and started to plane them flat side by side. Then I sawed the right angle with the table saw. Some hours later I had the squared keel beams.
After that they still have to be trimmed according to the dimensions of the plan. To do this, I printed out the plan from B&B Yachtdesign in 1:1 scale and cut it with scissors. I taped this template to the oak beam and traced the shape. Then I used the miter saw to make the angle cuts with some safety distance on the outer edges of the keel beams. I’ll do the tapering and cutouts for the stringers later when the keel beams are already glued in to the floor section.
It is also essential to round off the top edges before glueing in the keel beams. Rounding them off when they are installed in the boat is to hard.
The keel floor on the left has 2 peg holes for anchoring the mast supports of Frame D`.
There is an excellent plan to set up the jig from the US-CNC-Kit supplier B&B Yachtdesign. However, it is important to think about some details before setting up the jig. This will save you time-consuming doublework. I put many ideas from my colleagues who have already completed these steps during their build into my concept.
The first thing I needed was a underlayer foil to protect the floor from dirt. A laser-level is a must have. It’s also worth thinking about how you want to turn the hull later and maybe you need later support rollers to move the jig / hull.
I bought 6 meter long spruce / fir squared timber and at the same time Siberian larch in 6 meter length for the stringers. In order to protect the workshop floor, I lay a thin cardboard to the floor and fixed it with tape. Then I installed the workbench at the head end. I attached the laser level at the hight of the waterline to the workbench. So I have a fixed reference point and can check the symmetry of the construction at any time.
To strengthen the jig I installed some struts to make it torsion-resistant. I checked repeatedly all dimensions with the laser and a long aluminum slat.
In total i needed ca. 42 meter squared timber.
2x 500 cm longitudinal beams -> 10 5×115 cm cross beams -> 5,75 10x 150 cm frame beams -> 15 1x 300 cm v-shape in front of the jig -> 3 2x 80 cm S frame beams -> 1,6 4x 150 cm bracing beams -> 6
Spring is here and boat building is picking up speed. There is fantastic news. Thanks to the help of my colleagues from the sailing club I finally found a bigger workshop to put the boat together and bought a Harbeck BT 2500 trailer. Thank you so much for your support.
In my opinion, the best thing about the ClassGlobe concept is the combination of an ocean-going but still trailerable boat. My dream boat is developing.
I used the spring offers from a ship electronics dealer to set up the electronics for my boat. Bought a B&G plotter and a VHF-AIS as well as a PLB device for personal safety equipment. The construction of the keel is progressing. The profiling of the keel fin and the rudder is currently being milled at a CNC company. The keel will be welded by the end of this month.
The upcoming grinding work will be very exhausting. That’s why I invested in really good machines again. A Festool LS 130 linear sander for small fine corners, a Mirka DEOS 343 CV slider for the ordinary jobs and compressed air slider Festool LRS 400 for sanding the large hull surfaces have been added to my tool portfolio.
Last summer Christian (CG #103) and I casted the keel bulbs. See the documentation here: https://minisailer.ch/?p=160
Now they have to be planned and balanced. We have built a grinding mount to plane the surface. We filled the holders for the bulbs at the end of the box with plaster. With this helper we were able to trim the keel bulbs with the electric planer to a weight of 70 kg. When planning, it is necessary to put some oil on the surfaces to make the work easier. Now they have to be drilled for the 3 bolts to mount them on the keel fin. A tough sunday workout for Christian who has lifted the bulbs more than 50 times and planed off all together 15 Kg of lead from all 4 bulbs.
This week I made good progress with the boatbuild. I am very happy to have the Selden mast and the Blueshark parts in my workshop. The packages arrived this week. Many thanks to Jane for the logistics. It is very motivating and a good feeling when the parts from all over the world arrive here in time.
I made frame A in a similar way as frame E. I do overlapping joinery at the joints of the slats. Frame A is a watertight bulkhead. So it is closed with a 8mm Okoume plywood sheet. I add 10mm in the thickness of the douglas fir slats (50mm instead of 40mm) for reinforcement reason in this area of the cockpit floor while the construction is heavy loaded from the main sheet traveller. In addition it will help when the crew is jumping around in the cockpit. I spent approx. 30 hours of work.
Frame A while assembling on the workbench in my basement workshop.
I choose Frame E as the first frame to be done. I fixed my drawn 1:1 plan on the workbench. The planed Douglas fir slats are cut to size, halved joint to strengthen the connection and then rounded on the insides of the frame with the router. This saves me time later when I have to sand it. The slats where glued with epoxy and fixed with clamps to the workbench while curing. Then the plywood gussets where glued and screwed to the joints. Finally I filled the cavities of the joints / plywood gussets with Styrodur and all corners with a microballon thickened epoxy putty. All together it took me approximately 30 hours of work including wood cutting. Later before mounting the frames on to the jig, I will put on 2 epoxy coatings.
Lateral view to the douglas fir joinery on the starboard top corner of frame E.
