CNC Plans not Included

You have to account for the glass overlaps everywhere or you'll see lumps..., and no, high build won't fill the weave. If you don't provide rebates for the glass overlaps you'll see all that through the paint. All your going to get is a finished outside surface in a mold, the inside will need a lot of work.

Building the mold will be more work than fairing and finishing the actual boat. This is why molds aren't used for 1 off constructs unless they are high budget builds - like mega dollar racing machines ala French ultime tris etc...

The furniture and cupboards inside a cruising boat hide a lot. You can make that work for you as much as possible. I noticed the sig45 uses a panel to hide the hull to deck join and they have fitted lighting and cabling behind this panel as well. Lots of Clever elements to that boat if you analyse it carefully.

 

I'l take another look, it's a beauty for sure.

 

I just had another thought... I kinda did this year's ago in a different way but for the same result, bear with me...

One might be able to spray an in mold coating down (epoxy types now avail) onto a polished flat table mold, then lay a thin veil type cloth over that, say 100-200gsm woven. Using un waxed polyester, wet it out and let cure. Once cured, peel it off and use it as a veneer to line the hull between bulkhead landings above cupboard level. Simply apply some bog with a 2mm notched trowel, and carefully press it down with a squeegee or plastic knife. It should go down straight over the peel ply surface on your hull.

Lay up a big peice of the stuff and cut it to fit. Only thing is it won't work for compound curves...

If they were flat panels, the veneer could be glued on during the infusion... kinda stuffs up the bulkhead landings tho...

 

Yeah liners are tempting. If your going to do that though why not just use cheap formica laminates.

Edit: check out this ready made stuff - https://youtu.be/SSD70-Je0KI ... available in lots of finishes and inexpensive. These would be perfect for ceiling areas. I would still frame it with a recessed area. https://www.frpshop.com/products/frp-panels/frp-liner-panels/

I once laminated fancy hardwood veneer over cheap laminate to get a luxury look on a domed ceiling. Came out beautiful but not really a time saver ... unless as you say, the edges terminate on a bulkhead or are recessed by fairing a grid around them.

I wonder if you consider the bulkheads and furniture are pre-finished, the outside of the hull is ready, the floors don't need fairing if you cover them up, take out all the areas hidden by built-in furniture etc ... It might be easier to just to fair, especially if you do it before adding the bulkheads.

On the mold taking long to build. Carpentry is my forte, that is the easiest part for me. I will actually take pleasure in that while Fairing I will avoid like the plague, that is where my labor dollars will be spent.

 

Was checking the SIG 45 out again. Hard to tell by pics but the interior looks like it has just about all a person would need.

The only changes I would like to see
- Side cabins extended aft with a more protected bulkhead helm. In which case I wouldn't enlarge the interior but add a storage for kayaks, sup's, etc built in.

- Raise boom and add a hard bimini

- Add davits for a dingy.

- Hull extended if needed to accommodate extra weight from dive tanks, dingy, elec drives/batteries ... I see Ocean Volt outfitted one.

Did all that just ruin the performance? ))

Here is the top photoshopped in. I guess it would have to be a complete new design, that would be costly.

 

They've already done it...

I'd also have a really good boom tent made up for it. Raise the topping lift some and you'd have a great outside area when at anchor.
They also have a little wind break window which pops up from the forebeam beside the mast, did you see that also?




For the helm- unless your racing or some other bizzare reason- you wont be out there steering, the autopilot will be on and youll be drinking a beer, reading a book, or such like...

I think there is plenty of available space on this thing for a cruising couple. Even 2 couples. Kayaks and the like would be tied down up on the front trampoline. Id probably haul out the dingy on the rear trampoline and tie it down in front of the mainsail traveller. You can use a little crane extending from the rear of the boom to help with that if need be.

And yes, extending something like this out to 50ft would be terrific and add a bit more usable space and weight carrying capacity in a few areas... although an even larger sail plan and rig would be heavier to handle, the rig on this thing is pretty big as it is... of course id be looking to build my own carbon mast and boom, but for a 50ft performance cat, thats alot of carbon and some pretty expensive sails... might require deeper pockets than i have :O

 

Yeah I just saw a video of that one, it's sweet.

Rob Denny, I think, has a good carbon mast maker, prices seemed very reasonable. You might want to contact him about that.

Kurt Hughes has a couple of designs that come in an open bridge deck version plus he says this on his site...

Here are a couple of the designs with open bridge deck options. I don't really like the look but probably wouldn't take much to sleek them out.

His designs range around 5,500-8,000 plus whatever extra for mods and you get cad or cnc files. It might be a possibility.

http://multihulldesigns.com/designs_other/49cruisingcat.htm

http://multihulldesigns.com/designs_other/outsider48cat.html

The SIG has two versions, one of them is carbon reinforced and the other I believe is mostly carbon. No way I have enough to build out of carbon unless I win the lottery, it's regular glass and that's good enough for me.

 

Check out Basalt fibre.

http://www.lbie.com/n3011.htm

http://www.colan.com.au/compositereinforcement/stitched/basalt-stitched-fabric.html

 

Heard about that stuff. Is it catching on? Have to look into it further.

 

i dont see what all the rave about basalt fiber is? Its heavier than glass, and has a modulus much lower than carbon so its about as useless as **** on a bull for boat building.

The main structural design consideration with a boat like this, (and any boat design really) is stiffness - hence you need high modulus fiber if you want it to be significantly advantageous over another.

To build a high performance cat with a moderate cost, i would use glass over foam everywhere, except the main beams and spars which would use carbon purely so i could reduce section size for equal stiffness. The reduction in section size and quantity of fiber and resin would offset most of the increased cost of carbon in these areas so you get less windage and weight for a similar pricetag...

The total weight difference on a 50ft cat designed in carbon sandwich compared to glass sandwich is about 200kg. Theres not much in it... This taken from shuttleworth design of his Dogstar 50 performace Cat article;


Materials cost GBP weight Kgs
Glass all foam 36000 4200
Glass foam, Nomex topsides, bulkheads and decks 41000 4170
Glass all Nomex 48500 4090
Carbon all Foam 46500 4070
Carbon all Nomex 58000 3920


Jorge, the problem with kurts designs is they are very heavy on curves... very little flat panels used. His designs would be very labour intensive to build because of that. You really need a designer who appreciates the labour savings to be made from using only developable surfaces to create desirable looking yachts...

 

Interesting statistics!

Grainger is working on a design very similar to the SIG open bridgedeck - http://www.graingerdesigns.net/cats/flying-fish-11/
Don't know if that will include the larger model 50 but I expect it would. If you google his flying fish designs, you find a bit more info than shown on links of his site.

If Salon is eliminated, helms are eliminated costs should come down. A 60' might be an option ))

 

Yeah nice looking boats and following the minimalistic approach.

All flat panels save below the waterline- again a good approach.

Good designer, will have a good value when it's built- more good vibes

His weight figures are a bit of a mystery tho, he seems to think the 45ft version will weigh 6 tonnes? I would have thought it would come in lighter than that, closer to 4 tonnes... something doesn't add up there but in guess the design isn't finished yet either so probably just a conservative guess at this stage...

 

Yeah, resale value!! Big one for me.

Going to start thinking of how to remove more stuff. I don't really like losing the Salon but if it's got a full roof and open to the air it might be perfect. Would give the cockpit a very luxurious feeling.

I plan on sailing mostly in warm climates but I do want to explore the frigid areas as well. I saw that the Maine Cat uses a hard bimini with soft curtains, guess I could rig the same quick-remove system.

http://www.mecat.com/boats/maine-cat-41,

I will mail Grainger as the date gets closer. I got the feeling he gets a lot of mail from people that are just dreaming, he was nice but short.

 

You can do compound curves like this, you just need to mold the lining skin off the external finished surface of the area that needs a lining, quite common on yacht headliners back in the 70/80s, often had the molded non skid in it.
Jeff.

 

Good call jeff- , but dont stop there, how would you go about building a 50ft cat?