Traditional Build with Corecell

Groper-thank you and much respect. I ogled your work and build before purchasing plans from Richard Woods. I had a lot of fun watching your drone video of the boat and reef with my wife as well. She asked me when we were going there and was informed it was a wee bit far.

I realize fairing and sanding is part of this plan. I only want to get the shape right, not the shine.

I'm quite convinced the best method is exemplified with this video. Of course, the hulls in this video were not self contained. The hulls for the demountable boat are rainproof and fully enclosed which means each hull can be treated almost as its own boat (with the exception of control systems and beams).

https://youtu.be/b-Wfv01nXTY

Of course, in a cruel irony; they used infusion on the outside of the hulls I believe, but these hulls are round and mine are not. I plan to put rebates in at the chines for the tapes and overlaps. I think there will be plenty of fairing, but I'm going to equip well with some flexitools. I am not unfamiliar with sanding. I had a job years ago and sanded for hours everyday.

I really must give Richard some time to give his opinions. He was willing to help me with the male mold, but the full female mold seems easier.

I have 12' 9" of headroom, and the hulls on the molds are about 6' up to the top. There will be plenty of in and out; that is true. I am still pretty agile, but am 50 years old and my back is not so good for heavy work. The in and out could be reduced if we left the transom off until after the last bulkhead, and then it'd only be up a couple of steps, which is probably what should happen.

I think the best way to go would be to build the full female mold with a break in the mold at 48" to accommodate the reverse chine, glass past the last bulkhead position and do all the internals from stem to stern. Once completed; it would be possible to build the deck, but for the beam sockets. Then lift it out and flip and glass the outside. The deck could be glassed over the reverse chine (gunnel) prior to flip.

I'd rather not glass the bottom until after the flip. I think I'd put plywood on the bottom of the mold at the keel to avoid any deformation or damage to the corecell with all the traffic (probably 1/4" ply inside, too) on it prior to glassing the outside. Glassing the outside in pieces prior to putting in the mold wouldn't be so great because overlaps would be nicer done like a canoe (full piece over both chines (port and star), 2" over the keel each way to over each chine)

I think it all makes a lot of sense.

Hopefully Richard will approve of and support it.

This demountable boat is really a unique design that makes it possible for me to own a Wood's cat. I am hoping to build a launch trailer that assists with the assembly. I'd like to take the boat to the Bahamas via Florida and Alaska via Seattle someday; perhaps even a trip to St. Johns, NL. Home the 2nd year of launch is probably going to be near Jeff Ilse in Minnesota on Superior.

I am very grateful to all here who have posted. Thank you.

 

The method shown in your video is suited to non developable surfaces which is why they are doing it that way. If the surfaces are developable, as your design is, then there are much faster and less costly methods. This is why the designer of the boat in the video , jeff schionning, created a new design called the Arrow series which are all 100% developable but with a very similar look and style to the GeForce series. This is because they are faster and cheaper to build from pre made panels rather than with frame and batten molds etc.

Think about it- there is no less than Double the amount of work to do it that way. After its all laminated on the inner skin, ypu have to repeat the lamination again on the outside! With pre made panels there is no laination of panels, only joins, and if you make your own panels via infusion you get both sides at once!
Its alot less work...

 

The nice thing about the Wood's design is that I don't need to worry about thermoforming the corecell very much. There is only one twisty area in the build at the for'd section of the keel.

Again, thanks. I do appreciate even if not in full agreement. This is all new to me, so I have to do what I think will work for me. It might not be the easiest for someone else, but I'm really keen on this female mold idea. I'm the sort of person that would be paralyzed with uncertainty. The mold erases all of that. And the half mold drawings are done, so getting to the full mold drawings is not too tough.

Time to wait and see what Richard has to say about it all.

 

Beamreach, just search for Infusion epoxy, I bought from a wind turbine builder who also sell supplies. Fun exercise, 80 foot blade turning 100 rpm, what is the tip speed and G force exerted?
I bought 1 1/2 hour cure rate, longer is available.

http://www.carbonfiberglass.com/Resin-Systems/Infusion-Epoxy

 

I started knowing nothing as well and on a small easy boat but I infused.

The hardest thing for me, on my build, was having to finish things the hard way after I learned more of the process.

So just know up front, for any method you choose, there will be frustration ... And then just push through that and get it done. Then on your next build you will have a clear idea of how you want to build.

I know some people may not get the same feeling of satisfaction from building their own boat but for me it's indescribably fantastic.

The second hardest part was the fairing. If you have any budget and want to save your sanity, get a little help on that, even though you said you are good at that.

If toward the end you want to experiment with infusion, you might try infusing some single skin sheets or you could just manually do it as well and glue them on the inside, just fair between pieces. That is what I will be doing on my next build.

Good luck

 

Good Idea Jorge, he should go ahead and build his dingy now and Infuse that.

 

inflatable dinghy - it is a fishing boat, our use of a dinghy will be limited

 

fallguy; I still don't understand why you don't want to build a flat panel design with flat panels.

Andrew

 

A good question, allow me to indulge you with as much subjectivity as possible (in good humor).

First of all, I have never built with flat panel.

I understand it to be stitch and glue like.

There are 6 bulkheads and a front piece in 32 feet, or roughly 5 feet between bulkheads. The greatest distance between bulkheads is 2000 mm, or just over 6' (bunk area).

The station molds for the half hull molds are 900 mm apart; there are 11, plus the front piece (or twice as many).

I would prefer the boat hold its shape and I see little reason to build the boat over its bulkheads and risk having any shape issues with the final product.

Perhaps you have confidence it won't. I am inexperienced and so I don't.

Confidence is a key for amateurs and newbies. Rather than me playing with battens for hours with 2 people making sure I wasn't screwing something up, for me, it'd be far easier to build a mold that has a final shape I trust without checking and rechecking. A few plywood washered screws along the inside, a few screws along the battens on the outside and away I go.

Keep in mind; this is a catamaran, so I will be doing the same thing twice.

When I built my first boat; it was a Gil Gilpatrick designed Laker canoe. Still have it. Gil's book was written in such a way that it instilled great confidence in me. I read about 8 books on canoe building before I started. None of them gave me confidence. Collectively; they did, and Gilpatrick's text sent me flying over the edge. It was straightforward and made things seem easy.

For me, a mold makes things simpler.

Years ago, I built a deck on my house. I had an engineer draw the design. Everytime my helper took issue with our build, I told him to refer to the drawings. Of course, he really only wanted to argue, but it is a great way to build to refer to the drawings, or in this case; the mold. In the case of the deck; there was no argument, because my helper really only wanted the argument.

If you have built a few boats using flat panel construction; perhaps you'd have the confidence to rifle forward; perhaps even so without the experience.

For me, I want to know my hull won't have waves in it.

Quite honestly, I don't even know how the bulkhead and flat panels go together without the mold. I have visions of tape seams partially applied or misapplied. With the mold, everything is far more straightforward.

Additionally, I would prefer to glass the bottom of the hull like a canoe. That is, with a single layer of fabric over the keel and both chines, and another layer of fabric over the keel and the chine using rebates at the overlaps for easier fairing. You can't use that lamination method with flat panel without defeating the purpose of flat panel construction, right? But, with a full hull flipped upside down, I can prep the outside core a bit and laminate it in full sections with overlapping glass. Using flat panel; unless I'm mistaken, the seams are all joined with a simple tape joint. My seams will be taped and overlapped, so it should make for a stronger boat, or one less likely to every come apart.

On the inside, I can also rebate the seams in the places where you can see the hull (about 4 meters). The rest of the boat does not require fairing of the seams. Sitting inside the mold and developing a few rebates with an electric planer and vacuuming up the mess is a few minutes. Much faster than doing that on each panel each time.

Richard Woods really needs to have the final say in it all. And he is on vacation right now. I'll let everyone know what he says.

 

Yes building with prefabricated panels is stitch and glue like.

Yes you can build the hull bottoms canoe like as you describe. This is one of the common approaches, you build the bottoms referred to as hull shoes first. Position these in a simple jig (female stations) and build upright from there on. The jig even for much bigger boats is usually only 5 stations.

To build your own flat panels you do not have to infuse, but I would strongly recommend that you do as it is very easy and very low risk of anything going wrong. The major concern is losing power and losing vacuum.

If you really really dont want to go down that path than a light vacuum bag pressure is enough.

Building your own panels allows you to rebate the edges where the tape joins are going to be if you wish. Ideally you would build full length panels, in your case 32 feet long. But half size would be fine also.

Building double sided flat panels on a table using infusion is VERY EASY.

Wet laminating on a flat table and then bagging is easy but you are exposed to fumes and contact with the resin to some extent.

Wet laminating inside female and over male molds is much harder especially on vertical surfaces. Contact and fume exposure is greatly increased.

If you haven't done so already have a look at this thread, http://www.boatdesign.net/forums/report.php?p=303449

Come back with further questions

Andrew

 

Andrew ...link failed or..?

 

I could laminate the inside skin on the table, but to do overlaps in the fashion I wish on the outside requires laminating on the full boat (on the outside). I watched a video of Ocean's Quest being laminated on the inside and it looked rather simple (they did it up and down).

https://youtu.be/UXC1nCzRTm0

I do not know how they did the outside lamination, and, of course, the inside of the float is not seen, so they were not worried about final exterior appearance.

I did it with a canoe, I can do it with the whole boat. The only real concern is whether the epoxy would run when fully vertical. I can minimize runniness by making sure my environment is cool enough and using peelply. That is easy to do in a climate controlled environment which I have.

I'm convinced the best way for me to build the boat is in a full female mold; laminating everything in place. I could place the panels into the mold and then remove them and laminate on the table, but I don't see much advantage. I can use raptor staples to help hold the fabric. If I use peelply, I should be able to reduce the resin content to reasonable amounts for a home builder.

The boat build will go much faster with a mold for me, so I will use a mold.

Very few people have the confidence to build a boat. Don't discount confidence in success stories. If you think about Fossett, he was a man who had a ton of confidence; it drove his success and even his demise.

So, the mold might be a crutch. Fine. I'm okay with it.

The people posting here have done a tremendous service to me already. They showed me that building with a female mold versus a male jig is much better. I don't see that advantage in the flat panel method. Richard calls for overlaps at the chines in the lamination schedule. You can't do overlaps in flat panel builds, right?

 

thanks Beamreach; I will just give directions to the thread this time as it is easy to find.

It is the top sticky thread in Boatbuilding, called "Boat Building Projects Underway"
Post #17, page2 by Alan M

Fallguy, I haven't given up on changing your mind yet, yes you can build your hull bottoms first with overlaps.

 

Alan's boat project was very fun to read. Thanks for the link. As you can see from the pictures; he still used 4 female mold stations to hold things together. Was that a cnc they used to cut the parts out of balsa core?

What is the big deal if I use 11 stations versus him using four stations and I cut and measure foam by hand versus a CNC? The only big gain I can see doing flat panels might be a little easier to glass and epoxy one section at a time. But the tradeoff is I can't overlap glass at the seams from one panel to the other without all sorts of temporary mold making and handling massive finished panels. My back will not like lifting all the finished panels around either.

I'm even more convinced to build it in a full female mold and glass it all in place. The only worry for me is bubbling in the laminate, but I'm hoping the peelply and staples will help.

 

The way it works is using the panels themselves as fairing battens. I would not suggest you do as I did and bend the panels around the bulkheads as they pull a bit on each bulkhead and your left with a slightly wavy panel which then needs fairing again. You can do it this way however if you very accurately build in all the furniture or stringers which will define the fairness of your topsides when you wrap them around the hull -but this defeats the benefit of easy access through the open sides... Catch 22 in that regard. All said and having done it once already, I'd opt for female stations and use 100% finished panels. Finished bulkheads bonded in also after that...


By using the female mold stations and flat panels, the panels themselves sit fair in the stations. You then simply drop in your bulkheads and glass. You can see from Alan's post that he had a 44ft hull shell completed in 8 days, save the deck which is deliberately left open until much later in the build. You can't beat that in terms of time spent vs result achieved.

If you make your own flat panels on a perfect infusion table- the panels can be finished including gel coat if you so desire.

Taping panels together is very simple. You wet out the glass tapes on a long table and roll them up into a wet roll. Then you take it to the seam and roll it back out straight again. It literally takes about 30 mins in total to complete a full length seam like this. It takes a bit longer to complete coved seams where the angle across the seam is less than 180degrees a you have the extra step of applying thickened resin and coving it neatly before adding the glass over the top.

For panels completed like this I like to leave a small gap between panels which you simply spatula some thickened resin into before applying the wet out glass tapes over the join.

Rebates in the panels can be made by using thin 2mm polyethylene hard sheet plastic on the table where your seams are to be. See my build thread to see it on finished panels.

Ideally you would have your finished panels CNC cut, however this is impractical unless you use a system like Duflex and their z joint to link multiple 4x8 panels so that each can be CNC cut sepereately then joined into full length panels without taping and raised bumps to fair out.

Making the panels yourself you can get the sheets of foam CNC scored so that they are lightly marked in your final patterns. Once you glass over the foam, you can see the score through the glass and cut the sheet back to the visible lines in the core. Spending a few hundred dollars doing this will save you heaps of time and gives you perfect accuracy. You do need a full set of CNC plans from RW tho - you should ask him if he can supply. The female stations are preferably also CNC cut at the same time...