Before laminating the hull it is necessary to round off the corners because the fiberglass fabric cannot bend around sharp edges. I also sanded the plywood to make it clean and smooth prior lamination.

Choosing a transducer modell for the echo sounder gave me some headaches. The ClassGlobe 5.80 class rules allowing a simple depth gauge. A log / speedometer or other multi-sensors are not permitted. I decided to assemble an Airmar P79 in hull transducer. It can`t be placed on the wooden hull structure and must be cast in a layer of epoxy directly to the glasfiber hull construction. So I had to drill the hole for this transducer before laminating the hull. To do this, I drilled a 10cm hole with the circle cutter in the floor plank directly in front of frame D. I closed this hole again with 20mm thick foam and secured it from below with a plate and a support.

Installation scheme for the Airmar P79 in hull transducer.

Transducer hole with foam block from the inside of the hull.

Support of the foam block while laminating the hull.

I have done the lamination in 2 steps:

1. Laminating the edges and plank connections
2. Hull lamination

Step 1: Laminating the edges and plank connections

I laminated the edges with 600g/m² roving glasfiber according to the plan. I covered the area of the bottom plank, the stem and transom with 2 layers of 600g/m² (first layer 10cm and on top of that a second layer 15cm width).

I covered the plank connections with 15cm 600g/m² roving glasfibermat. I also attached 2x 600g/m² roving fabric in the area of the dagger board holders. Finally I applied peel ply for surface conditioning.

After some days of curing, I sanded and filled the transitions to avoid possibly air bubbles when laminating the glassfiber fabric.

Step 2: Hull lamination

According to the building regulations, the hull must be covered with 1000g/m² fiberglass fabric. Due to the easier handling, I decided to make the fiberglass structure in 3 layers and used woven glassfiber fabric 345g/m² and 1 meter width. I laminated wet-on-wet in one pass with overlappings of 5-10 cm. After applying the first layer I added reinforcements with 600g/m² roving fabric in the area of the skeg, the keel plate and a band round the hull to strenghen the hull in the position of the shroud chainplates. I used epoxy from the brand R&G which I knew from my previous boat building so far. Namely it was the resin L and the slow-setting hardener GL 2. This epoxy resin is thin flowing and slowly curing. It soaks the fiberglass fabric very well.

I built a rolling scaffolding that was moveable along the hull from the transom to the bow. I pre cut the fiberglass mats a day before. The order of applying the fiberglass fabric was starting at the transom as follows:

1. layer fiberglas fabric.

2. layer fiberglas fabric

3. layer fiberglas fabric

4. layer fiberglas fabric

5- layer fiberglas fabric

5. layer fiberglas fabric overlapping the transom

6. layer fiberglas fabric

7. layer fiberglas fabric

8. layer covering the transom with peel ply

9. layer fiberglas fabric

10. layer fiberglas fabric

11. layer fiberglas fabric

12. layer fiberglas fabric

After applying these 12 coats, I planned to take a break to eat and drink. Then i was able to proceed with this 3-layer system to the bow.

The advantage with this method is that I can stop the laminating process at any time and simply cover the laminate with peel ply and continue the next day or after a few days. For example, if you are a small team and you have to take a break or there are problems with the resin etc. you`re able to stop and continue later.

Time for the big day.

Christian (CG #103) and Thomas, a friend of mine from sailing club, came on a saturday to my workshop. We worked great as a team. I mixed the epoxy, added the pre cut fiberglass mats from above, applied the epoxy and vented while lying on the scaffolding.

Christian laminated the starboard side while Thomas took care for the port side. I mixed each 1 kg of resin and 300 grams of hardener in a 3 liter bucket. I took control portion of each mixture. This way i was able to check the curing later.

In total we used 26 kg of epoxy resin. Laminating 4 layers (3x fiberglass + 1 layer of peel ply) takes time. Time was flying so fast. With a short break, the three of us took 12 hours and bravely held out until early morning. Very good job guys. The result is excellent.

General tips for laminating:

A few days before the laminating day it is time to check and control the material. Then there is still enough time to order missing things. Calculate is there enough resin / hardener? Are there enough tools (brushes, rollers, mixing sticks and containers, venting rollers, a second scale to be on the safe side if the usual scale is defective, protective material such as gloves, suits, respiratory protection, etc.).

Maybe it gives you confidence when you mix the epoxy and check if it is curing and that all materials are compatible. There’s nothing worse than finding out that the resin doesn’t work!

I laminated the raw Okoume plywood planks. They was not prepainted with some epoxy layers. Keep in mind that the wood could pull out the epoxy of the fiberglass fabric. You have to apply a liquid epoxy layer to the wood about half an hour before. Immediately before placing the fiberglass mats, apply another good layer of epoxy. Always make sure that each layer of glassfiber fabric is well soaked with resin before applying the next layer. If the fiberglas becomes translucent then you can be sure that is well soaked with epoxy resin.

When putting on the peel ply, don’t apply too much epoxy resin. Otherwise waves could form. It’s not a big problem to sand them down later, but it’s better to avoid this.

Epoxy overload.

After the lamination is done and the peel ply is on it is best to continue working with the ventilation rollers for about half an hour and press the fiberglass fabric down to the surface while it becomes more and more sticky.

I personally got some tips from Joachim (CG# 165) who also wrote a very good blog about laminating the hull. Thank you Joachim!

Some more impressions from laminating the hull ClassGlobe #66:

Trolley with fiberglass and peel ply rolls.

Epoxy mixing bar.

My co-wokers Christian and Thomas.

Thank you so much guys for your great effort and the unforgettable moments when laminating hull ClassGlobe #66.

Before planking the hull i had to trim the stringers into shape. This step must be done very precisely to avoid any bumps in the planking that gives you significant amount of work when filling. I started to trim the stringers with the electric planer. The finishing was done with the hand plane. Finally, I used my sanding board to shape the stringers. I use a measuring stick to check whether the smoothing is sufficient.

Handplaner with guide rail

Sanding board

Measuring stick

Stringers shaped and ready for planking

Be careful with the 30mm stringer at the flat hull side (not the 30mm chine stringer) between frame B and frame C. Due to the bend, it can protrude slightly outwards. If you now try to trim back these protruding part of the 30mm stringer, they will be thinned out and therefore bend even further outwards.

The hull is covered with 10 mm Okoume plywood. The bottom is planked with 20mm (2x 10 mm).

I have done the planking in 4 steps:

1. First bottom planking
2. Side panel planking
3. Chine panel planking
4. Second bottom planking

This order may only be possible if you build by plan. The CNC kit planks are short cut and therefore a different order of planking must be chosen (1. side planking, 2. chine planking, 3. 2x bottom planking).

I cut the planking to size by placing the large 1.22 x 2.50 m panels on the hull, marking and cutting them out. I left about 2 cm overhang on each side. I dryfitted the planks and fixed them with clamps on the stringers. I climbed under the hull and marked the position of the frames and stringers from the inside. Then i took of the planks again and drilled the holes for the screws.

Step 1: The acces to the bottom of the hull was easy by climbing onto the stringers. I glued the planks with thickened epoxy (epoxy + cotton fibers) and fixed them with stainless steel screws. In the area where the planking rests on the frames I used 5×40 screws. To fix the planks to the stringers 5×25 screws was the maximun and I had to be careful that the screws didn’t come out on the underside of the stringers. Choosing the screw position is not easy because you cannot place the screw heads too close to the edges. These screws could bother you when sanding and rounding the edges later. As a solo builder, I used a support to help me hold the plate when gluing the bottom plank.

Step 2:  Side panel planking was a straight forward job. Before planking I cut off the butt blocks that will be placed on the inside of the joints.

Butt blocks astern (upper section is extended for reinforcement of the series drogue chainplate attachments).

Butt blocks in the cabin (plus extra 10mm plywood reinforcement for the shroud chainplates as per plan).

I used little helpers that I attached to the 70mm stringer to hold the plate when gluing. Again i fixed the planks with 5×40 stainless steel screws whre the planks meets the frames and 5×30 screws to fix them on the stringers.

Immediately afterwards I attached the butt blocks to the inside of the hull at the joints of the planking. With screws (3×16) and clamps i was able to press the butt blocks to the joints.

Butt blocks in the cabin fixed with clamps while gluing.

Gluing the side panel planks.

Then i had to trim the overlapping 2 cm of the bottom and side planks in the chines section and had to sand the stringers again.

Step 3: Fixing the chine planks where they meet the straight sections in the back of the hull was as easy as the bottom and side panel planking. The front chine planks in the bow section gave me some problems. With a lot of strength, straps and clamps, I managed to bend the 10mm Okoume plywood panels into shape.

Step 4: Finally, I glued the second bottom planks with a layer of thickened epoxy and fixed them with stainless steel screws (5x40mm screws to the frames through the first bottom planks and 3x16mm screws to the first bottom planking). I had to make sure the epoxy wasn’t thick. I started screwing in the middle of the boat and standing on the plank with my weight to let the epoxy flow out to the sides.

Finally, I sanded the planks where they are screwed onto the stringers and rounded the edges of the planking to easily apply the hull glass around the corners. This lowers also the risk of damaging the fiberglass when sanding the hull.

Next comes the lamination of the hull.

Finally the stringers are glued. It was a tricky and sometimes physical job.

You can find information about cutting and preparing procedure of the stringers here:  (see my blog: https://minisailer.ch/?p=362)

Preparing:

First of all, it is very important to get a good knowledge of the ClassGlobe 5.80 contours. The stringers must installed according to the chines and shape of the hull. Therefore I studied the plans and many builder blogs. Then i was able to develop a feeling for the angulation and twist of the stringers.

Since i`m building from plan i had few information about the dimensions and position of the cut-outs for the stringers. The exact meassures are not included in the ClassGlobe 5.80 plan. One more time i have to take these details from the CNC-kit parts. Thanks i`m in touch with builder colleagues. Some stingers (mainly the one of 30mm dimension) are placed in the middle from the joints of most frames. But not in the bow area.

I split the stringers gluing in 3 steps. First i installed the 30mm stringers. This is the easiest part of this progress and you give the sensible frames construction stiffness that you`ll need when putting in the following stringers. The second step was to glue the 50mm chine stringers and last ones where the 70mm stringers at the deck level. It is important to glue the both corresponding stringers in one time so there will be no twisting of the hull.

Attention! The stringers are the foundation for the planking. Every mistake here will punish you with bumps in the planking that later give you a lot of work when filling and sanding. So be sure and check the position of the stringers with a level before gluing.

Tools:

With some helpful tools you can make the tough job of cutting out the frames, bending and shaping the stringers a little bit easier.

Some self-made tools are useful to get control wether the stringers are placed sufficiently, to bend them and hold in place (2 forks for the twist, templates and a gauge to measure the hight).

Jig modification and strenghening:

The jig needs to be strengthened as there is a lot of torsion in the bow area when installing the stringers. If frames D, E and the stem are not properly attached they could get warped.

I built scaffolding to the sides to make it easier working at height and to have better ergonomics.

Cut-out`s in the frames:

The best way to cut out and grinding work on the recesses in the frames is to use a reciprocating saw, japanese saw, chisels and carpenter`s mallet, as well a small belt sander and wood rasps. For sure you need a lot of small clamps and lashing straps to hold the stringers.

I clamped the stringers in place and marked the position and angle of the cut out. With a mixture of drilling, sawing out with the Makita reciprocating saw and grinding with the belt sander and wood rasp, I got very precise cut-outs for the stringers.

Check again and again in between with the helper tools.

30mm stringer:

It is best to start with the 30mm stringers. As soon as these stringers have been glued, the construction is fixed and can no longer move. I was so glad when those stringers where glued. Finally, I no longer had to measure and check the distances and remeasure again and again. When doing the cut out in the stringers i checked theses recesses with this small 30mm try in block.

In the bow area there is a lot of twist and bending to the stringers. I was lucky to have these self-build forks to manage the twist of the stringers.

In the area of frames D` and D the stringer makes a strong kink. Here I have made an attachment to the jig post so that I can attach a strong clamp to press the stringer.

The chine stringers:

I made bending the stringers a little easier by already planing off the 50mm chine stringers. With this they lose some regidity and are easier to bend.

70mm deck level stringer:

This stringer isn`t lowered into the frames everywhere. At frames S, C and D` and D it is fully integrated. At transom, frame A, frame E and stem cap this stringer is only 45mm attached. 25mm are outside of deck level which will be planed later when the hull is turned and the deck is made.

When adjusting the stringer there is a lot of stress on frame S and it could get warped. Therefore i installed two bars while gluing the stringer.

Mission completed

Happy days are coming! The boat is taking shape. Heading forward now for planking.

I prefabricated the keel floors from oak wood (see my blog:https://minisailer.ch/?p=258)

The keel beam No. 1 and No. 3 are already glued in with the corresponding frames D` and C. Now the keel beams No. 2, 4 and 5 have to be glued.

First i checked the correct position of the keel floors with the string line level.

When putting in the stringers there is a lot of tension in the bunksides / keel floors section. I attached teo slats lengthwise to prevent any movement during gluing the keel floors and stringers.

In order to make the connection as stiff as possible, I was very precise. First sand the adhesive surfaces of the bunksides and remove dust / degrease with acetone.

I did all the epoxy gluing steps in one operation. The keel floors and bunksides where precoated with a thin epoxy layer so that the glue can penetrate the wood. Then the joints where filled with a thickened epoxy (Mix epoxy and cotton fibers). I applied the filets directly while the epoxy had not yet hardened. This way I get a better adhesive connection and save myself grinding work.

To get a proper fit I weighed the keel floors down.

Since I don’t have a CNC kit, I have to cut the bunksides myself. Here it is a great work simplification if you have ordered a CNC kit. I got a cutout keel floors template from Christian (CG# 103). I also copied the shape of his bunksides from the CNC kit and then built another template out of 6mm simple plywood.

With the help of this template I cut the two bunksides for my boat from 8mm Okoume plywood with a copy routing technique.

Since the okoume plywood panels are unfortunately only 2.5 meters long, I had to lengthen them. To get a good finish, I sanded the panels with the orbital sander before adding two layers of epoxy. Finally, i sand everything down again with 120 grit sandpaper to prepare for later painting. That way I’ve already completed this work and don’t have to do it in a crooked position when the bunksides are glued into the hull.

Now I had to come up with a method of gluing the bunksides in place, taking into account the frame C that is inside the bunksides. Not easy when you`re a solo builder. It came up with an extension construction of the jig upwards.

In order to glue the bunksides in the exact position and to keep them straight, I supported them with four squared timbers when gluing.

With rectangular strips on the aft joints on Frame A and towards to the bow on Frame D`, I created a strong connection by gluing with epoxy and additional screws.

With this preparation I was able to glue the bunksides, Frame S, Frame B and Frame C in one operation in a one night shift. I used slow hardener and immediately applied the fillets in the corners as long as the epoxy hadn`t hardened.

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.

It started with drawing the plans (see my Blog here: https://minisailer.ch/?p=70).

Finding douglas fir of good quality, sorting and cutting it to size took patience (see my blog: https://minisailer.ch/?p=87).

I got very good Okoume plywood from a dealer in Italy (see my blog: https://minisailer.ch/?p=92).

Next step was to create a suitable workshop with a large workbench (https://minisailer.ch/?p=175) and having the right tools (https://minisailer.ch/?p=83).

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.

Frame E astern.

Frame E bow side.

You can find more information about building this frame E here: https://minisailer.ch/?p=203

Frame D astern.

Frame D bow side.

Frame D` astern.

Frame D` bow side.

Frame C astern.

Frame C bow side.

Frame B astern.

Frame B bow side.

Frame A astern.

Frame A bow side.

You can find more information about building this frame A here: https://minisailer.ch/?p=213

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.

Transom astern.

Transom bow side.

Transom with daggerboard plates.

Building the frames was a blood-sweat-tear job. But also fun making the frames in my basement workshop during winter time. With a lot of tips from my classmate Christian CG #103, they ended up with a nice finish. See Christians blog for further excellent information about epoxy gleuing and frames build (https://www.argoworldwide.com/ClassGlobe5-80/Builders-Blog-Argo-103/index.php/;focus=STRATP_com_cm4all_wdn_Flatpress_35081877&path=?x=entry:entry230325-192653#C_STRATP_com_cm4all_wdn_Flatpress_35081877__-anchor).

In the end it feels great to finally start building the hull.

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

Hull construction is getting closer!