Build time 40ft catamaran

there are also torsional loads down the length of the hull and CCs are better at dealing with those than flat panels because you reduce the amount of pointload discontinuities. and in the real world you rarely have all your loads aligned with your squared panels

 

Rob you twisted my words again, as usual. I never implied or said that any of the boats I built were infused. I never said I was a professional boatbuilder. I never said we sent moulds to the USA and then shipped them home again. That's a crazy idea.

Instead I said "That Transit was built in the USA using hull and deck mouldings sent out from the UK in two containers"

400g/sqm is about half the glass layup that the French use on their 40ft cats. Maybe you should say how thick your hull skins are, just to clarify for others. Then they will get an idea of how much they can scrape a hull when beaching or coming alongside a concrete wall without piercing the outer laminate and exposing foam.

Richard Woods

 

On the CC female mold building question going to a mold frame and stringer layout then planking with a diagonal layer covered with glass is fairly straight forward. The "planking" is all going to be a constant shape taking some of the work out. Of course you'd have to fill/fair/sand, but only "one hull side" worth. So you've got 5 sides to make a cat but only one with traditional labor.

The other thing about CC is that panels can be used for more than just the hulls. Decks, cabins, cockpits etc.... I've seen some very attractive Newick hull plans, then there are the Marples and Brown Tri and cat offerings demonstrating the method. It is slower to fit interiors to curves but straightforward once you get used to it.

 

Nimble motors , we're not talking chimneys , we're talking boats. The only example of a lightweight structure was the tecktron 50. Chines are heavy.JP, Let's try building a chine A class hull or infused flat panel as light and fast as a nice cc one with the same stiffness, as a tester , I'd like to see that. To me the schionning compound curved "waterline" series hull looks nicer than the chine wilderness hull. Does anyone think a chine whitehall looks nicer than the real thing? Maybe it's just me.

 

If you want to talk about boats and beauty, then tell me about that butt ugly thing that hangs on the back of just about every catamaran I see.

 

Aesthetics is one thing, and its totally subjective, so theres no point discussing it further as everyone has different taste. If you like shapely things, then be prepared to do more work, thats the only thing worth discussing here. Many Beautiful boats are designed with no compound curvature, all the duflex kit boats from grainger, schionning, oram, kelsall, are examples of this... same with all the plywood simple curvature boats aswell... single curvature only, can make lovely shapes. Or it can be made to look butt ugly... its all up to the designer and and the buyers tastes.

Chines dont add bugger all weight either Barra, if the structure was infused in a mold, there would be almost zero extra weight - just a slight resin rich area on the chine, thats all. Chines are also stiffeners, so where you have them, doesnt require extra frames or stringers to stiffen that part of the panel. Intelligent design, makes use of the chines as stiffeners in the same way curvature does.

Curvature aids stiffness, theres no doubt. But flat panels with single curvature tortured in are faster to build. When i started building my boat, the initial design had alot of compound curves in it. I quickly realised the hassles involved with trying to get compound curved shapes into a sandwich structure. It almost exclusively makes infusions a single side only affair unless you have good quality (vacuum tight) surfaced molds to infuse in. If you dont have this tooling (we never do in 1 off builds), we use something like batten on frame molds and vertical strip plank it. After you wet laminate or infuse one side, you gotta flip it over and repeat the infusion/lamination again! Its very time consuming and you always have to fair both sides to get rid of the flow media print a (or glass weave) and all the glass overlap print etc. Flat panels and infusing both sides in 1 shot saves HEAPS of time compared to any other laminating method you can think of, one side is perfectly fair ready to paint directly, or can even be gelcoat finished with no after work.

So i redesigned the boat to take out all the compound curvature - after id already built some of it including the bulkheads- which i had to cut down as part of the modification. Single curves only, made everything alot easier and faster and did not require a great deal of extra stiffeners to support the chosen panel sizes and aspect ratios.

 

Yes groper I hear what you are saying. Every build method has it's pros and cons. One is unlikely to build a full mould for a one off so every chine join is taped and faired with the associated doubling up of laminate. Small
Amount in overall context but still heavier all the same. I had a quick glance at the wilderness 1120 study plans. Looks like around 450 sq meters of panel material required if this could be considered near enough to a typical 40 footer. Guessing at around 90m2 in the hulls. For those that have faired chimes in a past life would realize that fairing round bilge hulls is very little extra work in context of the entire project. From previously experiece working aloneI can strip a single 12 meter cat hull, glass, fair, undercoat, flip and glass the inside in 2 weeks working alone. The strong back and temporary moulds take 2 days from timber and beaver vomit to go.
How much quicker would flat panel to round bilge
Infusion hulls take to this stage. Can. You make more than one 12 meter hull panel in a day? Can you get a nice tulip bow if required or is the hull shape more restricted?

 

The quickest method of producing the Hulls only, is probably dereck kelsalls method whereby you do 2 full length infusions, and bend them using a jig with dart cuts in the flat panels, where the round bilge area lies. The dart cuts allow each finger to pull together a little, which gives you the compound. Once you have it held in place using ratchet straps on the jig, you lock in the shape by glassing over the bilge area.

I know i can infuse a full length panel working alone in half a day- done it many times. As to the rest of kelsall`s method, i cant say as i havnt done it - my hulls are not round bilge. Instead i designed a U-section below waterline (almnost identical to the americas cup catamrans) which i made from folding a flat sandwich panel. Kerf cut the core, and glass over the kerfs to lock in the curvature. Takes a couple hours to kerf it and bend it, and a couple more to glass over the kerfs. There is no added weight, as you dont put the glass on one side, in the areas you know your going to kerf cut... so leave the glass out when you set up the infusion... I have images in my build thread which show this whole process. I would have made them bigger and could have included the topsides in the same panel, but my workshop where i do all my infusions and laminations is just a double car garage... so i had to do everything in 2 halfs as i didnt have the convenience of a full length shed... its one thing i would definitely do differently next time, - setup a better building shed with a full length flat table... Rob Denny and Kelsall also recommend the same.

Im not sure what you mean by a tulip bow?

At the end of the day, any shape is possible, its just a question of how much extra time you wish to spend getting it...

Time to build hulls is hardly worth discussing tho, most of the time goes into the interior and all the millions of little jobs - there is so many linear meters of cutting and jointing and fitting of small details. You could just butcher you way through it and get it done quick, but for a nice job, completely faired and painted inside, not just covered up with carpet or spray fleck, takes alot more time than it does to simply build some hull shells...

 

The boat hulls are the most important part of a boat!
If not built well, a boat will be a disaster. And given how much time and money the rest takes, you better be damn well sure they are good before you invest the rest of the time and effort.

So this explains why it is discussed. And it also is a large material expense.

But then let's discuss the 'fit-out' or everything else. Where does the time and money go? Please can you experienced guys that have built hundreds of boats explain,
and I don't think I've seen a real breakdown.

It seems clear that diesel engines are a very big expense, and their installation is not simple.

 

I See........... ? http://curvelle.com/

 

outboards aren't cheap either. And there are still associated systems. remote controls, fuel lines and valves and supports, tanks, vents,drains, transoms, gauges, starting batteries, switches, house bank interface,charge controls, noise reduction,service access. That's just for the motors.

 

Nimblemotors

The amount of time involved in building a boat will be thousands of hours and by far the majority of it is involved in NOT building the hulls. That is if you want a simple normally fitted out modern catamaran.

I don't know the hours involved in many projects I have done but broadly the hulls have been about 15-20% of my boat projects. That is faired and ready to go hulls.

Hull internals like bulkheads take up time, the sub floors and cabin sole takes time, the internal fitout of the cabinetry takes a huge amount of time. Getting two hulls FULLY fitted out inside even before you start joining them will take longer than building them. In fact that is one reason I am less inclined to worry about fast build methods. I think one of the fastest ways to build a boat is to have ALL of the bulkheads and cabinetry cut out on a computer driven router so that you can reach over and install instead of measure. You can also make interior furniture on the shop floor and then install whole which I found saves lots of time. I think it may save more time than the time saved by using a method that is quick to the shell stage but is not highly accurate.

Aligning the hulls takes time and construction and installation of beams is a big hole. Then there will be a while where you get everything joined up and with more work you have a shell. But then there is a cockpit with backing pads for every fitting and all those funny corners. Then you have the bridgedeck cabin with its fittings everywhere. That's even before you go inside again to start on building in the electrics, the water system, the stove fittings and toilet system.

At the moment I am refitting Kankama. She is on the mooring so the work is slower than in a shed. I spend about 10 hours a day on the boat and some days I can almost not even see what I did. Often you spend 10 hours farting around with running hoses, wires and making mock ups of how the radios will fit in together. And then you have to try to make a new icebox - that took me three days! just for an icebox. It took me half a day just to remove the old one.

The hulls are not the boat and time should not be the reason you use a particular method. The fitout will be where your time will be spent even on a simple cruising cat such as the one I have.

Of course you can build a Piver Lodestar like Arthur Piver. He built his in months and then sailed it to New Zealand but it had no interior. It can be done but you should choose a simple boat with little interior.

cheers

Phil

 

Nimble, it really doesnt need to be spelled out does it?

Building and Reiforcements for;
chainplates, main connective beams, mast beams/bulkheads, huge bridgedeck floor, cabin top, the entire top deck, strong forebeams/forestay attachment, rudder posts ans steering systems, daggerboards and cases, winch pads and all other deck hardware for rigging blocks tracks etc and mooring ie cleats lifeline stanchions, window frames landings, steps and companion ways - thats just outside.

Inside you have, cupboards and benchtops for kitchen and bathrooms, sinks and shower sumps, tankage for water and waste and fuel, seating and tables and consoles, soles for flooring, hundreds of meters of internal taping on bulkheads and stringers, fridge and freezer compartments, plus more i cant care to remember right now... Then you have non structural work such as plumbing, electrical, drainage, mechanical, rigging, trampolines, hatches and portlights, and physically installing all the hardware we talked out earlier reinforcing to take it, winches and shiney bits... It just goes on and on and on... the outer hull shells are maybe 100 hours in a 3000 hour total build time...

 

David, given your great video history of the Ariki build,
we can see the progress.

Jan 2012 started with one hull popped out of a mold.
October 2012 two hull structures complete
Feb 2013, still working on the deck
October 2013 finishing cockpit, cover
Jan 2014 final fairing

So finished in 2 years, which is impressive, most of the first year was building the structure if I understand it correctly?

 

Yes I would like it spelled out, not just hand waving that 80% is 'something else'.
The only way to speed up the other 80% is to understand what is consuming the time.
That is THE POINT OF THIS THREAD isn't it?
I have never said building a hull SHELL is a big time sink.