MV catapult

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

Re: MV catapult

Post by groper » Sun Jul 07, 2013 9:59 pm

Had a week off work this week, which meant i finally had some good time to make progress on the boat...

Infused the other half of the roof, same as before, joined them together, and applied the first coat of highbuild paint to the cabin ceiling side and sanded it back ready for topcoating when i paint the rest of the boat. Got a few mates over and we manged to get the 92kg roof up as 1 peice.
Image

There is a bit of compound curvature in the roof, not a lot, but it transitions from a longitudinal bend at the front which you can see in the above pic, to a transverse curve in the aft. This means we had to do a bit of torturing through the center in order to get it into shape which is difficult with these very stiff panels. You can also see that the chamfered sides have dart cuts in the front so these can be pulled together and taped thus forming a chine with longitudinal and transverse curvature in the front of the roof section - we havent taped this yet but is next on the list after the tabbing is cured on the aft bulkhead.

Also did a bit of furniture work, made the cabin setee and finished the basic kitchen panels, and also finished the rear cockpit seating etc.
And guess what,-- EEK-- the first bit of wood has found its way into the boat :eek: Im doing the interior cabinetry from it as its just too expensive to do absolutely everything in foam sandwich...
And just another shot of some of the hull and steps down from the bridgedeck with the fuel tank closest the camera...

puremajek
Posts: 751
Joined: Thu May 04, 2006 7:36 pm
Location: Brisbane Australia
Contact:

Re: MV catapult

Post by puremajek » Mon Jul 08, 2013 9:54 am

Wow...its really starting to take shape, thanks for the updates.
James
______________________________________________
http://www.diycatamaran.com
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cruiserbill
Posts: 51
Joined: Mon Jun 13, 2011 12:04 pm
Location: Indiana

Re: MV catapult

Post by cruiserbill » Mon Jul 08, 2013 9:03 pm

Looking good!

Delcrestsa2
Posts: 5
Joined: Mon Jun 17, 2013 11:33 pm

Re: MV catapult

Post by Delcrestsa2 » Wed Jul 10, 2013 1:20 am

HI, your build looks very nice, I am new to this forum / site and at present unable to send a PM, could you email me at anglozulu@hotmail.com i would really appreciate if i could discuss a build that i am currently contemplating

Delcrestsa2
Posts: 5
Joined: Mon Jun 17, 2013 11:33 pm

Re: MV catapult

Post by Delcrestsa2 » Fri Jul 12, 2013 10:20 pm

Hi your build is really loooking good, and looking forward to strarting my own build
Do you have any alternate suppliers of infusion materials or suggestions, what can be used without purchsaing from the "composite" suppliers, ie bagging , peel ply, tape etc
thank you for posting your build, its been inspiring!

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

Re: MV catapult

Post by groper » Sat Jul 13, 2013 8:20 am

Bagging film I get from a packaging supplier, PE shrink film. Make sure it's virgin plastic with no pinholes.

Peel ply, from a textiles or fabrics wholesaler. Plain pale Polyester Tafetta, 80-100gsm weight.

Infusion flow media, from an agricultural / nursery supplier - 30% shade cloth. Infusion groove cut foam doesn't require a flow media however. Resin consumption is the same but the resin ends up in the bin with flow media, as opposed to staying in the panel with grooved foam... It adds about 400grams per square meter to your finished panel weight.

Also use 13mm irrigation lines for the resin feed and vacuum lines from same supplier.

Tacky tape, I still buy from the composites supplier, hard to beat this stuff, it's important to have a good seal even tho its expensive... I figure its worth it although I'm sure there's alternatives if you go searching.

Perforated film is also required with flow media, can only get it from the composites suppliers.

In bag resin feed, I've started using a combination of plastic gutter guard and cement board jointing strips. The strips are called divimold here in oz, they're a plastic mold for buttjointed cement board in house construction. The gutter guard under the divimold works well as an "in bag" resin feeder as it doesn't leave a resin blob on the panel. Took me a while to figure this one out... Setup looks like this;
In bag vacuum lines, spiral wrap... I get it from the manufacturer, took me a while to find them here in oz, they make it for hydraulic hose protection in the mining industry. Best to ask around over there. With experience, you can get away with other things for this purpose, I was considering using drip irrigation lines for this purpose as well... No reason it shouldn't work... I've also used hessian webbing, flow media etc... But in the beginning you should use something that won't block the vacuum pathway if it gets resin soaked or it can stuff up your job.

Look around for resin suppliers, I get my epoxy direct from the manufacturer, saves a bit of money. Same for the foam core. The resin and foam make up the vast majority of the cost.

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

Re: MV catapult

Post by groper » Tue Jul 23, 2013 4:33 pm

Cabin is starting to take shape... i made a template out of thin ply for the cabin sides as there isnt 1 straight edge in it anywhere.

ill trace this template out onto my foam and i think im going to infuse 1 side of the panel only - the surface that faces into the cabin so i get a smooth tool surface laminate in there. Ill bend the panel around and wet layup the outside to lock in the curve... i think ill rout out my rebates for the UD reinforcements around the windows, then glass the outside. Thats the plan anyway, its a pain in the ass trying to demold a single sided laminate tho...

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

Re: MV catapult

Post by groper » Sat Jul 27, 2013 4:17 pm

Its not too late you know...

What do ya think?

rexd666
Site Admin
Posts: 157
Joined: Tue Dec 15, 2009 7:15 am
Location: Melbourne, Vic

Re: MV catapult

Post by rexd666 » Sun Jul 28, 2013 11:02 am

Good idea based on what I paid for petrol this week. Assume you would need to beef up support across the front beam of the bridgedeck? Is your beam comparable to a sailing cat of the same size, I would assume a motorised design would be a little narrower.

Keep up the good work and posting progress, your infusion work and that of precat.nl has me thinking lots.

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

Re: MV catapult

Post by groper » Sun Jul 28, 2013 1:58 pm

Well not really, the boat was always engineered and designed like a sailing cat - so the beam is quite respectable at 5.1m - so its twice as long as it is wide or near enough 2:1. The righting moment is 50kNm so it will handle a decent size rig if i wanted it to. The mast beam bulkhead is already reinforced from original sailing cat inspired design, just need to add a bit more to it - depending on how big i go with a rig. My biggest concern is dealing with the aft buoyancy distribution - which was to reduce sinkage and trim under engine power, and also what to do about daggerboards... i dont think i have a choice but to make cases and boards if i go down this road as the CE vs CLR would give a very lee helm on the current hull.

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