High Performance MPX Foil/Self-righting Trimaran-The Test Model

Another small miracle: my Kodak camera stopped working about two weeks ago or so. Just for the hell of it I thought I'd try it again-and it worked! No idea why its working or why it quit-I'm just thankful because I can't get the new replacement camera to upload pictures.
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So here are a couple of pictures of the boat with the deck of the main hull ready for 220 after some minor filling. And you can see what the ama's(without the curved piece) look like dark gray....
But the really neat thing is I did a mock up(with aluminum foil) of the "Wand/Foil Retainer"(WFR)-my little "invention" that:
1) holds the wand axle and the dual wands, one on each side,
2) retains the foil so it will stay in position vertically,
3) allows the angle of incidence of the main foil to be adjusted by loosening two nuts and sliding the whole "Wand/Foil Retainer"(WFR) forward or aft.
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The WFR makes it a piece of cake to make a major foil adjustment in just a few seconds! The actual part will be made out of epoxy/carbon.

Click for a larger image:

 

MPX Test Boat

Some changes- new weight estimate based on the heavy filler ,paint etc
is now 15lbs(first target was 16.688lb) and I thought I could do it for 13.5lb.
I've spent lots of time double checking this so I'm confident it will be close.
Based on my experience with the F3 which was designed at 8lb and varied between about 7.5 and 8 depending on battery the SA is based on SA/lb. That boat had 1668sq.in of sail area for 208.5 sq.in. per lb. of boat weight.
The test boat will have 3181.78 sq.in. of SA(incl the wing mast) for 212 sq.in per lb.. As before it will be reefable.
This is one powerful sailboat, or should I say Fire Arrow--->

 

Hi Doug,

I am VERY interested in your design as a Stand Up Paddleboard, have you ever considered this option for this hull?

 

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No, I haven't. I think it is probably too big and would also have a lot of wind resistance with just a single person aboard. With two, maybe.

 

It seems very similar to this design, but I am very much the layman.

http://deanwatersports.blogspot.com/2011/08/boom.html

here is a hull shot from below

http://deanwatersports.blogspot.com/2011/05/design-simplified.html

Are any dimensions on this thread? I was considering a single outrigger design similar to racing outrigger canoes for a 14' or 16' stand up paddle board.

Unfortunately Dean Water Sports seems to be out of business.

 

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The fullsize hull is about 130LB , 3' wide and 16' long. Its carbon/vinylester.
I don't think it would be good for a standup paddleboard.

 

Well Doug I think you are right that 130lbs is a bit heavy. I'm really looking forward to seeing the trimaran mocked up.

 

34th AC

Have recovered from the heavy filler problem and am thru with 80 grit and ready for 220. However, I won't do that until the whole boat is assembled which is next:
1) Shape the "curved pieces"(see picture below-the "curved piece" joins the end of the cross tubes to the ama and increases reserve buoyancy w/o being in the water until it is needed),
2) build the jig to hold the two amas and two curved pieces,
3) glue the curved piece to the ama,
4) remove from the jig and carbonate the curved piece and reinforce the joint between the CP and ama,
5) cosmetize the carbonation-simple and quick,
6) cut the crossarms, and assemble the ferrules into them and add the anti-rotation screw,
7) Build the main, final assembly jig,
8) carbonate 10 joints and cosmetisize.
9) celebrate and take pictures,
10) finish work includes building the wand retainer, adding the rudder gantry,
adding the bucket seat supports and the removable seats(so I can get scale pictures), add jib boom support, add mast step, add three trunks and upper trunk plates, 220 sanding, make four foils while the hulls are being painted.
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So,it should go fairly quickly now.

picture showing hulls and "raw" styro "curved pieces":
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MPX Test Model

Heres what the "curved pieces" look like ready to be bonded to the amas and ready to be carbonated. All 80 grit is finished except on the transom where I had a re-fill. Once everything is assembled and installed I'll spray with primer and or duratec, sand with 220 and 320 and then have Matt paint. About the paint: assuming I can get the Dupont MS mixed accordingly the color will be "Bright Red". If you see a 2012 or 2013 red Chevy Spark you'll see the brilliant "Bright Red" they use. I found a website where you can get the paint codes for every car, now I just have to see if they can mix it here. This is the best gloss red I've ever seen.
Keep in mind that this thing will be almost 7' wide. Amas are in their relative fore and aft position as are the curved pieces.

click--

 

MPX/SRT Test Model

Here are some shots of the curved pieces and amas in their jig almost ready to be bonded and then carbonated. The last 9" of the bottom of the ama is set at + 2.5 degrees angle of incidence:

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Hi Doug, Its certainly an extreme looking boat, cant wait to see it all together.

My question relates to the curved beam to ama joins. To me it seems llike a relatively small joining area? What sort of stresses do you anticipate, I presume extra carbon reinforcement in these areas?

Also, why have such long (fore/aft) curvy beams when only such a small area is connected to the ama? Could a single beam (ala Garys Sid) be an option?

Might have missed this earlier, sorry if I did.

Keep up the good work, cant wait to see her sailing!

Cheers, DAVE

 

MPX Test Model

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Dave, thanks for the post and good wishes! I'm not sure I get "the long curvy beams"? The crossbeams are straight carbon tubes that intersect the curved pieces. I know this is a long thread but this has been covered earlier and I'll go over it again: the test model was originally conceived of to test the self-righting concept I have but at about the same time I conceived of that I came up with "MPX" foil system, which ,if it works, could be a significant advance in trimaran design. The foil system allows the boat to fly the main hull early(light air) and then have the main foils unload so that the ama foil carries the whole load. The system allows an oversquare tri to have excellent light air and heavy air performance.(if it works)
Now, the reason for the "curved pieces" is to increase the reserve buoyancy
of the boat w/o having to have large amas. The curved pieces will only see water in an extreme situation - and their buoyancy will be welcome in that situation. Also, they allow for high dihedral to help keep the crossarms clear of the water. The "self-righting" aspect of this design is now second priority for testing-it also requires that the boat have some ballast at the junction of the foils and daggerboard which version 1 will not have.
Hope this helps and I'll be glad to answer any other questions you may have.

 

MPX/SRT Test Model

The curved pieces are glued and taped to the amas. Tomorrow or Tues they'll be carbonated.
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MPX / SRT Test Model

Here is the boat half mocked up with the port ama in almost its exact position(a little bow down but close enough for jazz) : this is the correct dihedral.

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SRT / MPX Test Model

Carbonated the curved pieces and aft part of ama today. Intensely strong and weight within the estimate.
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See the very large hunk of styrofoam? That was just delivered and is the result of another middle of the night brainstorm. This boat is so big that if I set it up on the plywood table it would be difficult to move and difficult to get everything accurate. So I had Sharon(The Styro Lady) cut out a jig to my plan which will make assembly a piece of cake. May set it up tomorrow or this weekend.