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

Re: MV catapult

Post by groper » Tue Sep 17, 2013 5:15 pm

Yeah looks great, so howd you do it? Im assuming you cant just mix it all up and spray it, the little beads wont go through the spray gun nozzle no? did you spray the intergrip stuff on the wet paint or....?

Trev
Posts: 160
Joined: Thu Jan 15, 2009 2:56 am
Location: Moruya NSW

Re: MV catapult

Post by Trev » Tue Sep 17, 2013 6:44 pm

Mix the paint, add the beads and spray. we tried a top loader gun with no luck, we ended up using a "supa cheap autos" gun with a 2.5mm nozzle, and just hosed it on. The trick was to keep spraying, if we stopped something would clog up.
The art was in the mask up.
Trev

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

Re: MV catapult

Post by groper » Tue Sep 17, 2013 7:56 pm

Thanks mate - i have one of those guns lying around somewhere, havnt used it in decades... i think it has a 3mm nozzle IIRC. I never thought the beads would go through...

What sort of deck paint is the best for this, the same old 2pk polyurethanes as the topsides are done it, but in a semigloss as opposed to a full gloss? Or something else...?

dennisail
Posts: 61
Joined: Tue Feb 19, 2013 1:42 pm

Re: MV catapult

Post by dennisail » Wed Sep 18, 2013 11:14 pm

Good work as usual. Are you really going to put a sail rig on it now? Or wait to see how she goes as a power boat first? I second the notion of a hitchhiker style rig with only genoas, since its a powerboat first and sailing boat second. Should save weight and cost. See how it goes without any boards, then fit just one if performance is not acceptable.

44c
Posts: 1148
Joined: Tue Aug 08, 2006 5:08 am
Location: Hervey Bay, Qld

Re: MV catapult

Post by 44c » Thu Sep 19, 2013 8:26 am

How I did my non-skid.

Mask up, roll on some polyurethane paint, then sprinkle with glass beads. (the coarse bead blasting ones) I used a flour sieve to sprinkle the beads.

Let it dry, then blow off excess beads, then roll on another coat of poly paint.

I use a fine nap roller, the little foam ones would work too.

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

Re: MV catapult

Post by groper » Thu Sep 19, 2013 5:24 pm

Cheers for that fellas...


Dennis, im just gonna launch it as a powercat... when the time comes, the time when i feel i want a sail boat, ill look at slipping the boat and modifying it to suit. If my needs and wants change too much, i may just look at selling it and buying or building another sailing cat... the need to provide an income is teh only thing stopping me from just dropping everything and sailing wherever the wind blows me, 2 words - women and kids...

dennisail
Posts: 61
Joined: Tue Feb 19, 2013 1:42 pm

Re: MV catapult

Post by dennisail » Sat Sep 21, 2013 5:46 pm

hehe. I have no kids but a long term GF who loves the cruising life. That means we probably could afford a long term cruise with the boat we already have. I am good to go! But I want something like a 44c, hence my trolling of build logs.

However some people have annoying things like "careers". I mean what is a career other than a way to get money for boats? :mrgreen: Then you have even more talk that is contrary to the cruising life, such as the dreaded word "children" :evil:

dennisail
Posts: 61
Joined: Tue Feb 19, 2013 1:42 pm

Re: MV catapult

Post by dennisail » Mon Sep 23, 2013 2:11 pm


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

Re: MV catapult

Post by rexd666 » Mon Sep 23, 2013 2:44 pm

Groper,
Have you got a weight comparison back to hand panels? Saw you mentioned the groove cut foam with resin in grooves was 400g/m2 heavier than normal foam, wondering how that compares to the same on hand laid panel, if you have done any?
Steve

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

Re: MV catapult

Post by groper » Mon Sep 23, 2013 6:18 pm

I have a spreadsheet that calculates everything... panel weights via resin infusion, vacuum bagged or wet layup.

Its not a straight forward question to answer because it depends on the laminate. But this is how it works;

1. resin to fill the surface porosity of the 80kg/m3 density PVC foam = 300grams / m2 - this is the same no matter what method you use.

2. Th infusion grid scored foam holds resin in the grooves of the finished panel, so the weight of this additional resin is the volume of the grooves * weight of resin, which equals 400grams/m2 and only applies to this method. It doesnt apply to infusion with surface flow media or any other wet layup method etc.

3. The fiber/volume fraction or resin to glass ratio = 32% resin to 68% fiber weight with infusion - this is where the big savings are with infusion and by its nature, the heavier the laminates the bigger the savings are compared to wet layup which is around 50% resin - 50% fiber.
So, if we assume a 820gsm triax laminate (a common laminate i use) on both sides of the foam, we need 770 grams of resin per square meter to wet out both sides. The same via wet layup = 1640 grams. Big difference in weight and also cost here considering epoxy will set you back near 20 bux a kilo by the 200kg drum.

The weight of the same panel described above using 20mm foam thickness thus becomes;

4.82kg / m2 via flow media infusion
5.26kg / m2 via infusion grid scored foam
5.76kg / m2 via wet layup
4.9kg / m2 via wet layup then vac bagged - improved fibre/volume fraction but you still use the same amount of resin as wet layup initially.

The numbers skew more in favour of infusion as the laminate weight increases and less so for very light laminates.

Hope that helps?

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