MV catapult

Build logs from members building catamarans, trimarans and other multi-hull variants.
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groper
Posts: 239
Joined: Sun Nov 18, 2012 11:23 am
Location: cairns

MV catapult

Post by groper » Sun Dec 23, 2012 4:32 pm

Hi folks, great site for australian builders here, i only just discovered it recently but have been building for about 6 months now.

The boat is a self designed 35ft powercat, although it could be converted into a motor sailer or full blown yacht quite easily and the thought has crossed my mind numerous times... For a motor sailer, id consider a novel rig like the chris white mast foil type rig etc... The general arrangement is very similar to sailing cat, the mast could be stepped on numberous structural bulkheads with added reinforcing if i choose to.

But for now, its just going to be powered by 2 mid size outboards, either 70 or 90hp each as im looking for reasonably high speeds, cruising in the high teens or even low 20 kt range. The high speed and arrangement makes for a game / sport fishing usage, which was the intent of the design, but to do it with much lower fuel burn than typical game boats. Also the reason ive chosen not to rig the boat with sails, if i were considering much longer cruising type usage, i would have sails for sure.

So high speeds and fuel efficiency were my goals in this design. To achieve it, the hulls have a 16.5:1 length beam ratio with full transom sterns and the whole thing is light weight, built from infused foam sandwich panels. I make the panels myself in the carport, then assemble them under a temporary shelter in the front yard. I have limited space beyond a double carport to do all the glasswork etc, and the grassy areas of my front and back lawns where i cut up panels and grind off bits etc...

I designed the boat in 3D CAD software to get the aethetics i wanted, then transposed the sections and lines into 2D autoCAD to make myself a set of plans and get the frames nested and CNC routed down at the local cabinet maker on his CNC bed.

The assembly method is basically the same as a duflex build, except i infuse my own panels rather than joining the duflex together before assembly.

Heres a few pics of whats taken place so far, from the initial design to where im at now. Id like to share information and experiences with any like minded folks. Cheers.

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Last edited by groper on Sun Dec 23, 2012 5:07 pm, edited 1 time in total.

groper
Posts: 239
Joined: Sun Nov 18, 2012 11:23 am
Location: cairns

Re: MV catapult

Post by groper » Sun Dec 23, 2012 4:42 pm

Then after the shoes were turned over, i placed the infused bulkheads on station and plum them up.

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Then i added the inside chamfer panels, followed by lifing up the bridgedeck;

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Last edited by groper on Sun Dec 23, 2012 5:21 pm, edited 1 time in total.

groper
Posts: 239
Joined: Sun Nov 18, 2012 11:23 am
Location: cairns

Re: MV catapult

Post by groper » Sun Dec 23, 2012 4:46 pm

After that, i started on framing out the rear beam, and extended the floor out in the cockpit;

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groper
Posts: 239
Joined: Sun Nov 18, 2012 11:23 am
Location: cairns

Re: MV catapult

Post by groper » Sun Dec 23, 2012 4:50 pm

Now im in the process of making the top foredeck panels, already got the port side done, need to make the stb side over xmas break period and join them together before pushing the camber into it and taping it onto the bulkheads. 1 advantge of makign your own panels, is that all the extra reinforcing, high density inserts etc can be added during the infusion setup, so no need to cut up the deck afterwards and do all that fiddly hand laminating... ill post a pic of the setup soon...

heres some of more before the top deck goes on;

Cockpit looking forward;
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Integral fuel tanks;
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Last edited by groper on Sun Dec 23, 2012 5:24 pm, edited 1 time in total.

groper
Posts: 239
Joined: Sun Nov 18, 2012 11:23 am
Location: cairns

Re: MV catapult

Post by groper » Sun Dec 23, 2012 4:55 pm

Oh and heres a short vid of a rudder i built for a bloke that cruised into town on his duflex catamaran... i went down to say gday and have a look around his boat whilst he had it beached in the local creek. I noticed he only had 1 rudder and asked him if that was deliberate??? He looked under the boat and said "shit, i lost one!" i chuckled and offered to make him a new one as i have plenty of foam and glass offcuts laying around...


puremajek
Posts: 753
Joined: Thu May 04, 2006 7:36 pm
Location: Brisbane Australia
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Re: MV catapult

Post by puremajek » Mon Dec 24, 2012 2:30 pm

Groper

Really appreciate you taking the time to get all your data up to the site. The 'infusion' side of things is new to many here and many have asked about infusion.

Your build is looking pretty smick, well done. Look forward to the next photos
James
______________________________________________
http://www.diycatamaran.com
______________________________________________

groper
Posts: 239
Joined: Sun Nov 18, 2012 11:23 am
Location: cairns

Re: MV catapult

Post by groper » Mon Dec 24, 2012 6:48 pm

My pleasure majek, happy to help anyone with infusion, its the way of the future :)

Infusion is brilliant... so much less stress than hand laminating, no mess, it really suits home builders, especially those working alone like i am most of the time - i get the occasional help from my father when i need to maneuver larger pieces etc... The quality of the infusion is brilliant when you get it right, ie no leaks, and even very heavy laminates (the bottom of my hulls are 4 layers of 750gsm triax for beaching) the laminate is perfectly transparent. I use a spreadhseet that calculates all the costs and consumables, resin quantities, finished panel weights etc, and i have found that with a laminate weight of 1000gsm both sides of a sandwich panel, the costs break even at this point - that is, the reduced resin consumption entirely offsets the cost of the infusion consumables.

With heavier laminates, its actually cheaper to infuse because you using so much less resin in the laminate. 1000gsm of glass will have 500gsm of resin in it as opposed to 1000grams for hand layed.

Then there is the time saving, im sure that infusion is quicker in labour hours, in the long run. This is because your completing both sides of the panel at once, and on the tool side you dont need to fair or fill or seal coat it afterwards, you can go straight to high build paint, no pinholes either... The bag side still needs the glass overlaps faired as the thickness variations still print thru on the top. I dread hand laminating nowadays, i try to infuse as much as possible these days as its so much stress free, i can stop whenever i want to, take a break, leave it for a week and come right back to where i left it... just easy...

The stb side of the foredeck is just about ready to be laminated, a pic here shows the foam core glued together and cut to shape, coosa board high density inserts are glued in place for my bow cleat, mooring cleat and the front 2 stanchion bases on this panel. i havnt routed the recess for the escape hatch yet tho. The extra reinforcements will be added when i lay it up. This panel has 1050gsm bottom, 1270gsm topsides and it will finish at 38kgs when infused. It could have been lighter, but im trying to stick to the australian standard for FRP boat construction, and they stipulate rather hefty minimum laminates unfortunately...

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groper
Posts: 239
Joined: Sun Nov 18, 2012 11:23 am
Location: cairns

Re: MV catapult

Post by groper » Wed Dec 26, 2012 7:05 pm

Just trying to illustrate how im going about building this boat. This is typical of what happens for each panel in the boat, so here a few pics of whats transpired;

This is the second half of the foredeck, core setup with high density inserts and a recess for the escape hatch so the gutter mold will drop in flush as shown in the prvious pic.

And then it was a just a matter of setting the infusion so the part filled evenly, a little tricky due to the escape hatch recess which acts a race track path for the resin, but a little thought into the strategy and it was no problem using a type of fishbone pattern. Im now using all cheap ass irrigation tubing and fittings so the cost of consumables is reducing... it has not given me any problems at all thus far... shrink film for vacbag, shade cloth for flow media, polyester tafat for peel ply etc... last thing i need to improve is the spiral wrap, stuff like enka channel works better because it doesnt leave a resin imprint on the panel which requires grinding off afterwards... there has to be a cheap, readily available substitute for this...

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So now both halves are infused, and soon i will tape them together and bend the camber into it over the bulkheads in situ. The smooth side of the panel has been used as the bottom so the ceiling will be essentially fair and require little overhead fairing inside the cabin of the boat. The topside is non skid finish so i figured this would work easiest... Nice to see Jim, one of the easy builders on this forum, dropped in today for a looksee aswell :)

groper
Posts: 239
Joined: Sun Nov 18, 2012 11:23 am
Location: cairns

Re: MV catapult

Post by groper » Thu Dec 27, 2012 6:14 pm

And so both sides of the deck are up;

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rexd666
Site Admin
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Re: MV catapult

Post by rexd666 » Sun Dec 30, 2012 1:22 am

Groper,
Just wanted to say thanks for posting, looks great. I take it you are mostly infusing on a table to make flat panels. I just got a package in the mail this week from Fram with an infusion test kit, just need to get a sample of foam and pump and I can try it out.

Look forward to reading more.
Steve

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