Nice, very nice??
I have just a quick question, how heavy is the hull right now?
Gio
Gio,
Actually the first thng I did was put it on the scale. It weighs in at 15.23 oz About 425 grams).
Not to bad I guess.
-Tom
sorry…just have to: when will the world understand that the international measure system MKS is?? (GRIN)
bah…have to use my converter again…[;)]
Wis
_/ if it isn’t broken, don’t fix it! _
That sounds awfully heavy. My Venom weighed 142 gm with the gunwales install. 355 gms. ready to sail minus rudder keel and rig. All elec including battery in boat. What weight carbon did you use. I think the Venom is one layer of 5 oz. kevlar. I don’t think the Mistral was a light boat so the hull weight shouldn’t matter.
Mihelich
what weight cloth did you use? I would have to agree with hoj, that that seems pretty heavy.
-Dan
Yes, that?s heavy, way too heavy.
The mistral is beamier and definitely heavier than a venom, (just the recommended bulb is 4 pounds), but you should be able to build a boat way under 6 pounds ready to sail.
With CF a single layer of 5 oz. sandwiched between two layers if light (1 oz) fiberglass should be more than sufficient, that and maybe less epoxy.
If you have questions or want to be sure you may want to contact Jim Linville, the USOM class secretary, the is an avid builder and extremely helpful ?
But regardless of the weight, the hull looks good very good Tom, looking forward to see the rest.
Gio
Tom,
Have you calculated your cloth weight versus your resin weight? Did you vacuum bag your layup? I would seay you probably have a pretty resin heavy hull. The whole point of a female mold like what you have made (which is great by the way) is to allow you to vacuum bag the layup and still get your fabulous finish on the outside.
I think 2 layers of cloth was overkill. Heck, carbon is probably overkill. A single layer of carbon will be stronger and stiffer than the single layer of Kevlar that the Venom uses. So if you are going to use carbon, I would have used one layer and vacuum bagged it. The Cobra Hull that is sitting dormant in my basement waiting for me to pay attention to it appears to be a single layer of carbon cloth and it is more than adequate strength and stiffness.
But you have a mold so you can pop another one out overnight!
- Will
Will Gorgen
What weight was the cloth? one layer of 200g plain weave would have been enough, provided you addd re-enforcement around the keel box area and the bow. Even if your not vacing it you should be able to get it a hell of alot lighter. Using peelply inside will also help draw out the resin even with a hand layed peice and alow you to stick things inside later w/out needing to key the surface too much…
Luff 'em & leave 'em.
When I laid up the F100 2 layers of 195 gram carbon (0 - 90 deg & 45 -135 deg orentation)
over a male mold with peel ply, I think the weight off the mould was 250gram (will check in my book when I get home)Added uni carbon at the load points (front rudder, keel pivot and rear rudder)
Then I sanded quite alot of the outside and inside.
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Hey guys,
Thanks for all the comments. That is how you learn things. I do realize this beast is on the heavy side. I still have enough carbon for a single layer layup. Believe it or not I have a vac bag kit still in the box that I have not tried yet. I just did not want to try everything at once and overload myself. We have a mold as Will said, just give it another shot. Now that I understand how the gel coat flows in the mold, I will try a single layer of carbon and use the vac bag system. Can anyone point me to a vac bag site which would show how to bag a hull in a mold like this?
I will let you know how it goes.
-Tom Think light [:-angel]
BTW I just weighed the cloth cut to the size for the mold. It weighs 138 grams dry.
I must agree with everything said here … it’s a very nice mould but one layer of CF will be enough. My IONA 10-rater (152cm long) weighed about 330 grams. I too used the wet layup and will try another one with vaccuum …
Wim
Don’t forget that if you are doing a wet layup and pulling a vacuum on it that you are going to need a path for the resin to go. The cheap way is to run a piece of poly rope around your mold (bag tape will hold it in place) If you want to do it right then you run metal coil around the edge of the mold… but in either case you have to give a way out for the resin the you are going to squeegee out of the mold. Use a little motor oil on your spatula to help it slide along and work the excess resin to the edge, down and out. Take a glass jar and make two hose fittings for your vacuum line to pass onto so you can trap the excess resin before it goes back to your pump. Becareful when working out the excess resin… make sure you don’t get too carried away and create a dry spot.
After you have done this a few times… you will understand why pre-preg cloth is the ONLY way to go if you are going to do this a lot.
Or use a breather layer over breadwrap to soak up the excess resin, pretty simple and works well (the breather layer can even be csm glass if you cant get hold of the right stuff). Theres alot of info on vacing in a thread not so long back, a quick search should find it…
Luff 'em & leave 'em.
Mihelich,
That is one great looking boat.
I have a question. How is the Carbon wrapped at the back and front of the boat? If it is all once piece where does the excess fabric go? Can you post a picture of the front and back and a brief description of how the Carbon is laid in those areas? It would help those of us that have never attempted this understand a bit more.
Oh by the way thanks for the pictures you have posted so far…they are worth a thousand words.
Tom
Seawind #80
Tom,
Since the carbon cloth is uni-directional, it formed very easily to the stern shape with just a gentle dapping with a brush and epoxy. Plus the vaccum sucks it into the corners nicely. As for the bow, I just slit the cloth and layed one half around the nose and then layed the other half over the top.
-Tom
Well,
We gave the vacuum bagging a try. You can see from the picture I just gave the bag some slack and used racing tape (duct) to seal it to the edges of the mold.
The result was a hull with a weight of 235 grams.
Can it be lighter? For sure with different cloth but frankly I am wore out from this step [:-banghead] and I am moving on to bigger and better parts of the construction.
-Tom
For the deck I am trying something a little different. I am using a composite honeycomb with a carbon sheeting. This stuff is 96 grams for a 12" x 24" piece. Light as a feather. This way I can have a structual deck with no supports. This stuff does not flex. Could I have used Monocote for the deck like everyone else? Sure… but what fun would that be. [:-boring]($25 a piece by the way)
-Tom
Here is a shot of the deck so far.
I thought I would try something a little different from the normal flat stern. [:D]
I will now look into mounting the keel and mast support. Kind of a open stern look. I realize black might be a little hard to see in the pictures. Sorry. We will load it up with graphics once completed.
Tom
BTW, I may have to stop the project for a few weeks now to get the race car ready for the SCCA National Runoff’s at Mid-Ohio. I need to shift the focus to the big race. Kind of the Olympic’s of club auto racing in the USA.[:-jump2]
Tom,
I am sure you have taken care of this, but in case someone else is also thinking of using honeycombs in their boats, just a little reminder that this stuff is usually made of paper with Aramaid/Kevlar fibres mixed in it. If it gets wet, it behaves pretty much like normal paper and gets somewhat flabby.
I am sure different brands behave differently, some better, some worse.
I used it to make a hulll out of ultra thin glass with honeycombs in between. I was sure that I would manage to seal it in completly to avoid water soaking in, but there was on or two pinholes (as always) and so the water got caught in the middle between the two glass layers that are glued to either side of the honeycombs. (Approx. 150 ml)
The hull sides got very soft and it took me quite a while to dry it out again.
Since I was never sure if I had managed to seal the hull completly after that, this turned out to be one of the biggest motivation to go and build another ship…
I am sure its not that much of an issue for a deck thou.
Just my two (Euro-)Cent on this.
Marcus