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

[Doug Lord]

MPX Test Model

Darn that stinking real life stuff.

Nothing should be allowed to interfere so close to a project finish.

We have all been waiting long enough.

That said, tend to what you need to take care of.

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Thanks. You're right.

 

[Doug Lord]

SRT / MPX Test Model

I just spoke to Matt(Falcon Marine) to set a tentative date for Phase I of painting which will be spraying the boat with Duratec. Phase II will be the final coat,unless the painter thinks he can spray either Duratec or a special primer they have to fill 80 grit scratches-which is doubtfull. So I'll have to wet sand after the first Duratec coat. That should take about two days.
I'm hoping to be able to take the thing to Matt Thursday or Friday of this week -at the latest next Tues. or Wednes.. And maybe have it back painted by the end of next week-I said maybe.....
In the whole saga of building this thing I have almost never been held up by not being able to sand on our porch. Somehow the wind was always from a direction that didn't blow dust thru the screen toward the neighbors porch. Never had a complaint and it always worked out. But today it's 15-20 out of the north and stops me dead!
So I'm doing the final drawing of the mainfoil adjustment device and wand holder, and the daggerboard, rudder ,mainfoil and rudder foil layout.
The daggerboard has a tube running full length with a pushrod inside that connects to the flap on the bottom and to the wand shaft on top. The wand shaft uses a bellcrank to make the conection and the bellcrank is also attached to a spring that holds the wand against the waters surface.
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So stay tuned -going to start moving fast ,I think.

 

[DennisRB]

Looking good. Hey can you please give a short design brief again? This thread is long at it appears the goals have changed from the beginning. Its not going to self right anymore is it?

 

[Doug Lord]

SRT / MPX Test Model

Thanks, heres a sort of summary post. The self-righting will be tested down the line. The high dihedral and "curved pieces" are part of that system as well as being good allround. But the foil system has taken precedence in testing because the potential gains are so great. If you have questions don't hesitate to ask:

As I've developed the SRT concept using the MPX foil system, the foil system has taken priority in terms of testing over the self-righting concept for the time being. I think the foil system has a lot to offer, particularly on small tri's. Thats what this model is all about.


I always hear that foils are too complicated, cost too much etc, etc. I always hear that a high performance tri wouldn't interest the target market because(see 1st sentence).
1) There are reasons I suggested using small amas: they weigh less and they cost less,
2) With the savings from the small amas foils would not be a problem,
3) Since I have yet to see an under 20' high performance tri designed to fly the main hull with ama foils and foils on the main hull-how can anyone say it wouldn't be attractive to the target market?
----a. Speed is fun
----b. Foils aren't just for speed- they dramatically improve handling if designed and implemented correctly. The system I described earlier with ama foils and foils on the main hull is different than any tri I have ever seen. Most tri's have a single daggerboard and single rudder-the only difference with mine is the addition of a foil on the bottom of each. And single ama foils. All the foils would be easily retractable fascillitating saling off a beach. Since the amas are small and light why not have plugin cross arms? Or use a variation of Gary's single cross arm.
----c. Modern foil systems can be almost automatic-they aren't complicated and offer too much to be shelved.
----d. The RM(righting moment) of a an 18X 18 or 18X 16 tri is too great to allow the main hull to fly even with a single person sitting in the center until the wind is 15knots or above. Many sailing areas in the US have 10knots or less year round. To make it fly earlier you have to add enough SA that you'll have to reef early and the enormous SA will cost more and be difficult to handle. Thats probably why you don't see small tri's that can fly the main hull-and are also fast.
But the solution is simple and elegant:
---by using the two foils on the main hull(main foil + rudder foil) the boat can be designed to lift the main hull in a 5 knot breeze!
---This is important: the main foil begins to unload as soon as the main hull lifts off and the ama foil begins to take more and more of the load untill at speed "X" the ama foil supports 100% of the load(not the 70 or 80% of the Mod 70's) and there is little to no ama or main hull wetted surface-all automatically. More than that, the induced drag(drag due to lift) is reduced dramatically on the main foil + rudder foil which are relegated, nearly 100%, to controlling pitch of the whole boat-not lifting the whole boat.(Much better pitch control than a "normal" tri.)
--- And most importantly the sailing angle of the whole boat(angle of heel) is automatically controlled and maintained.
---This allows the crew(1 or more) to sit comfortably in the center of the boat while the boat sails at a max heel angle of 10-13 degrees. No running side to side. No pitchpole. Dry, not sitting in a fire hose spray(main hull is in the air). More comfort, much more speed and able to perform like this in very light or heavy air.

 

[Gary Baigent]

Doug, I like your dihedral design (well, it's very similar to my own stuff, so I have to say that) and understand that the cowlings aft of the floats and connecting the beams, are there for spreading loads and cutting weight but, on my light and wide boats, sometimes tacking in a seaway and higher winds, can be a tricky manoeuvre; you have to time everything perfectly, meaning helm, releasing main, coaxing that wide/light platform through the eye of the wind and onto the new board - and sometimes you get stopped head to wind and sail in reverse. You quickly reverse the helm, hold the wing mast up to weather until the boat is pointing correctly for the new tack, drop mast spanner, sheet in, up helm and away. Sort of three point turning. Now your floats are mounted forward (to halt nosing down) and there is nothing much aft of centre and if you are caught aback, there is not much to stop you rocking backwards, only the main hull, which, with your light design, will be reversing at a rate of knots. Could be tricky situation.
What I'm saying is I think it would be better to shift your small floats aft, so they're more central and not biased forward. Your foils will stop nose down problems anyway.
But you'll find out if there is a problem soon enough and maybe in Florida's lighter winds, getting caught reversing at high speed will not occur. Cheers.

 

[Doug Lord]

Doug, I like your dihedral design (well, it's very similar to my own stuff, so I have to say that) and understand that the cowlings aft of the floats and connecting the beams, are there for spreading loads and cutting weight but, on my light and wide boats, sometimes tacking in a seaway and higher winds, can be a tricky manoeuvre; you have to time everything perfectly, meaning helm, releasing main, coaxing that wide/light platform through the eye of the wind and onto the new board - and sometimes you get stopped head to wind and sail in reverse. You quickly reverse the helm, hold the wing mast up to weather until the boat is pointing correctly for the new tack, drop mast spanner, sheet in, up helm and away. Sort of three point turning. Now your floats are mounted forward (to halt nosing down) and there is nothing much aft of centre and if you are caught aback, there is not much to stop you rocking backwards, only the main hull, which, with your light design, will be reversing at a rate of knots. Could be tricky situation.
What I'm saying is I think it would be better to shift your small floats aft, so they're more central and not biased forward. Your foils will stop nose down problems anyway.
But you'll find out if there is a problem soon enough and maybe in Florida's lighter winds, getting caught reversing at high speed will not occur. Cheers.

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Thanks Gary! The reason for the curved pieces and forward position of the ama hulls is to help to facillitate self-righting-the curved pieces are there primarily for buoyancy-they have about as much as the ama hull does. Same with the dihedral which needed to be high because of the curved pieces.
The primary testing is for the new foil system now and later on I'll see if the self-righting concept can work.
After initial testing ,if weight is ok, I think I may add fairings to the cross beams-but that's down the line.
I'll keep in mind what you've said........

 

[Doug Lord]

MPX Test Model oops

Trouble with the sails: Scott(Sails by Morgan) e-mailed me today apologizing for not having the sails ready-I told him I was behind as well -no worries. However, it turns out that the Sandy Goodall(sail designer who did the main design) patterns were done on software that is incompatible with Scotts sail cutter so the main may have to be done all over again. Scott has used Goodall for a lot of projects including for the sails on my 16' full size monofoiler so it's kinda hard to figure how things got this screwed up. I guess Sandy changed his software and didn't tell Scott? At any rate, no sails for a while. Luckily I'm about two weeks behind(or so) so I imagine it will all work out.....

 

[basil]

What!!!! this is not about self righting? We've waited months - read thousands of mainly unnecessary words (some 300 posts) and ongoing excuses for the delay and now you say this all about foils - Come on Mr Lord when are we going to see your self righting trimaran???

Bas

 

[CutOnce]

What!!!! this is not about self righting? We've waited months - read thousands of mainly unnecessary words (some 300 posts) and ongoing excuses for the delay and now you say this all about foils - Come on Mr Lord when are we going to see your self righting trimaran???

Bas

Basil, give Doug a break. Anyone who has taken on a project like this knows the path is longer than expected, it takes you places you never planned and it costs more than you ever imagined.

Besides, the problem here is a simple typo, not quiet de-prioritization of the major feature advertised and promoted. And it isn't even a misspelled typo - it sounds exactly the same.

The thread should be labelled "High Performance Self-Writing Trimaran: The Test Model" and when you take that into consideration the project is already an amazing success. I don't know about your expectations, but there certainly has been a shipload of high performance trimaran writing produced ahead of schedule.

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CutOnce

 

[Doug Lord]

MPX /SRT Test Model

What!!!! this is not about self righting? We've waited months - read thousands of mainly unnecessary words (some 300 posts) and ongoing excuses for the delay and now you say this all about foils - Come on Mr Lord when are we going to see your self righting trimaran???

Bas

======================
Gee Basil, thanks for you interest, but apparently you missed the part where I said that the foil testing is now the number one priority, but the self-righting will be tested down the line.
As you probably know from following the thread so closely no changes to the boat were made to allow foil testing to become the first priority. The boat-I'm sure you've seen the pictures of the first float test of the fully assembled hulls-is the exact design required to test the self-righting concept-all I have to do is add lead to the daggerboard.
Thanks for your interest!

 

[cavalier mk2]

Basil, give Doug a break. Anyone who has taken on a project like this knows the path is longer than expected, it takes you places you never planned and it costs more than you ever imagined.

Besides, the problem here is a simple typo, not quiet de-prioritization of the major feature advertised and promoted. And it isn't even a misspelled typo - it sounds exactly the same.

The thread should be labelled "High Performance Self-Writing Trimaran: The Test Model" and when you take that into consideration the project is already an amazing success. I don't know about your expectations, but there certainly has been a shipload of high performance trimaran writing produced ahead of schedule.

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CutOnce

That is a catty thing to say! The title says trimaran and Doug is certainly trying!

 

[Doug Lord]

MPX Test Model

Finished the 80 grit sanding of the curved pieces and aft end of the amas as well as the aft end(gantry mount) of the main hull and the crosstubes.
The crosstubes and the verticals presented a nightmare to sand down the superfill because of the difficulty in getting to them by hand. Thursday night I had a brainstorm to use sanding belts(from a belt sander) so I got 3" and 1" belts yesterday.
Boy, did they work well-was able to knock them all out in an hour-it would have take 3 hours by hand.
Just some small touch up fills and the boat is ready for Matt to spray with primer or Duratec and then the whole thing has to be 200ed and 320ed which won't take long at all.
PS- will try to add the mounts for the wand holder tonight and tomorrow....

 

[Doug Lord]

MPX/SRT Test Model

Going to Matt tomorrow or Wednesday. Decided to go ahead and install the plates for mounting the wand holder. Used little 8/32 bondable fasteners sold by Dragon plate(see left picture below). In the right picture the edges of the plates holding the fasteners have just been coated with Super Fil, very lightweight filler from Aircraft Spruce, and there is a piece of peel ply holding the stuff in place on the thick side. The plates are coverd with masking tape and when the tape is removed will be high gloss "natural" carbon fiber. Should look pretty good-we'll see.

Pictures-Left,an array of the bonded fasteners from Dragon-epoxied in place, Right, the instalation on the main hull.
click-

 

[Doug Lord]

MPX-Test Model

I went to get the paint this morning-"Dupont Marine Series". Matt of Falcon suggested this instead of IMRON because he has aff the stuff that goes with it at the shop. So, I had the number of the "Bright Red" used on some 2013 Chevys but the guy said they couldn't mix that with the Marine Series-just too new. So he picked out another red that, under intense light, was very similar. Oops, they could only mix that color in the Aviation Series!! So to save money I decided to stick with the Marine Series and use their "Journey Red" which is ok-not spectacular.
Heres something that really is spectacular: one quart of this paint cost me $250-that's DOLLAHS! Unbelieveable. One quart of white would have cost $60-the guy said the red is the hardest to produce. OK, I guess....

 

[CutOnce]

I went to get the paint this morning-"Dupont Marine Series". Matt of Falcon suggested this instead of IMRON because he has aff the stuff that goes with it at the shop. So, I had the number of the "Bright Red" used on some 2013 Chevys but the guy said they couldn't mix that with the Marine Series-just too new. So he picked out another red that, under intense light, was very similar. Oops, they could only mix that color in the Aviation Series!! So to save money I decided to stick with the Marine Series and use their "Journey Red" which is ok-not spectacular.
Heres something that really is spectacular: one quart of this paint cost me $250-that's DOLLAHS! Unbelieveable. One quart of white would have cost $60-the guy said the red is the hardest to produce. OK, I guess....

Red is not only hard to produce, it is a serious pain in the nether regions to get a quality finish from. It is a semi transparent jewel toned paint, requiring lots of coats to cover faults in the surface underneath. For best results, a even dark grey toned primer will allow red to work best. If there is any variance in the primer coats, it may show through four of five coats of red.

I once painted a boat red. I'll never do it again. It takes two to three times the weight of paint to equal the finish from other colours. And $250 a quart? Sounds like military pricing to me. Imron I'll avoid due to the toxic off-gassing and need for positive pressure breathing gear. Two part epoxy automotive on good marine high build primer is now my choice for a dry sailed boat. Then again it looks like I'm in a different budget world if you paid $250 / quart.

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CutOnce