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RE: Nightmare MKVII Trimaran Build Log - 5/12/2009 12:04 PM   
TBK


 

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From: Ajax, ON, CANADA
Status: offline 		Started work on the carbon fiber main hull. In the photos below you can see I've installed the bonding strips, the fin/mast base support and the transom & rudder log. I used the same templates/design as the first boat. Next I will add the xbeam supports and servo mounts and internal turning blocks for the sail servo. These will be redesigned to be much lighter.

TBK

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< Message edited by TBK -- 5/12/2009 12:05 PM >

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RE: Nightmare MKVII Trimaran Build Log - 5/13/2009 1:28 PM   
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With all that experience you have gathered so far, there is little more I could educate/teach/tell you.

Maybe just this:
When I did my own trimarans, I designed each single component just like you -
and then I checked the weight of it, before I glued it in.
Several times I decided it is still too heavy/strong - threw it into the garbage can and re-built it.

This even happened to complete shells and floats -...-

Tough - but seemingly the only way to reach perfection.

Idealist

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RE: Nightmare MKVII Trimaran Build Log - 5/13/2009 3:28 PM   
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I will be following a similar trial and error process. The ultimate test is in the finished product and it's ability to perform without breaking. I still tend to err on the side of conservative, but I am going to push the limits a little this time. I used the same finbox/mastbase design as the previous boat however it was made with thinner materials, similar for the transom/rudder log. These are the two highest stress points where some rigidity is required. These will be the only full bulkheads used in the mainhull whereas in the previous boat there were 8 full and 2 half bulkheads used. The float hulls will likely have no full bulkheads, whereas the original had 5 full and 2 half bulkheads. I will be taking a lot of guidance from what has been done by others especially that German fellow who built a similar boat. In his main hull there were no full sized bulkheads used, even for the mastbase/finbox.

TBK

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RE: Nightmare MKVII Trimaran Build Log - 5/17/2009 2:46 AM   
TBK


 

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Status: offline 		With the long weekend upon us I will be able to get a substantial amount of progress done on the carbon fiber boat. Essentially I completed the imternal structure for the main hull and the two halves are ready to be bonded together. I will need to wait until my sail winch arrives before I can close things up. Here are some photos showing the internal layout. It's quite different that the previous boat and uses only three full bulkheads. The overall weight is at 30 ozs or 862 gms. I've also started on the float hulls adding the bonding strip to each hull. Tomorow I hope to get both float hulls completely together.

TBK

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< Message edited by TBK -- 5/17/2009 2:50 AM >

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RE: Nightmare MKVII Trimaran Build Log - 5/19/2009 12:55 PM   
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Status: offline 		I finished both the float hulls yesterday. The only pieces left to add are the transom and nose pieces. Here are some photos showing the internal assembly and one hull being bonded together. I weighed both hulls and they are about 1/3 lighter than my existing glass hulls. They come at slightly less than 1lb each - 15.4 /15.3ozs. I also made the new xbeams - again they are all carbon fiber. They are made to the same template as the glass xbeams. I'll post more photos today when everything comes off the moulds.

I also got a chance to get the finished boat out sailing again in some strong breeze 8-10 knots with gusts to 12. She really  performs well and accelerates quickly in a gust. I managed to bury the bows numerous times without flipping and I got her sailing up on one float a number of times. She seems to track very well even on one float. Ultimately I did pichtpole the boat and it went turtle and the end of the mast stuck in the mud bottom of the pond. I did have my chest waders on just in case and waded out to retrieve the boat. Wouldn't you know it that the pond was just an inch or so deeper than my chest waders and I ended up getting wet. anyways. Luckily the water is warm (but very dirty). The boat remained upside donw for at least 10 minutes or so as I struggled to get it. The good news is that even though it was upside down there was NO WATER INSIDE when I opened it up to check things out. That is partly due to the fact that I use small carbon fiber tubes to act as sheet guides and they stick out about the deck about an inch or so. Thus when the boat goes turtle they act to vapour lock the inside not allowing water to get in. Essentially the hull becomes a balloon  floating on the water. The only risk area is the tiller line exit points and they tend to stay well above the waterline when inverted. Unfortunately I didn't bring my video camera with me so I'll have to wait until the next outing for more footage. I am considering making up a new rudder with a small wing to add some downforce and drive the bows upward in a gust. The other thing I will do is add more mast rake again to load the back of the boat.

TBK

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RE: Nightmare MKVII Trimaran Build Log - 5/20/2009 11:50 AM   
Idealist


 

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quote:

ORIGINAL: TBK

I will be taking a lot of guidance from what has been done by others especially that German fellow who built a similar boat. In his main hull there were no full sized bulkheads used, even for the mastbase/finbox.

TBK


TBK

Just to let you know  - the "german fellow"  you are refering to - who built a similar boat - it is Eric Gielen, who helped me to build the plugs and the carbonfibre prototype of the Mk.VII here at Vienna!
And yes - he is German, but lives and sails at Vienna as well.

Idealist

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< Message edited by Idealist -- 5/20/2009 11:52 AM >

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RE: Nightmare MKVII Trimaran Build Log - 5/20/2009 1:26 PM   
TBK


 

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Thanks for the update. Judging by the pictures of that build he is quite a craftsman as well. You'll notice that I couldn't bring myself to remove all the bulkheads in either the main or float hulls. My gut feeling tells me that the boat might be a little too flexible without them, especially in the critical stress points. However I'm sure that I could be proven wrong on this so I've decided that I will build one more carbon fiber main hull with the absolute minimum internals - and you'll be pleased to know that it will be a MKVIII design (with the round bottom shape).  I'll get started on this once I've finished the current boat. I plan to make it so that I can interchange main hulls and use the existing Mark VII floats to start with. I am pleased with the overall weight reduction that I have achieved over the glass boat and I am hoping to keep the completed boat under 5 lbs all in. Once I complete the xbeams and weigh them I will pretty much know what the final boat weight is likely to be. More to come

TBK

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RE: Nightmare MKVII Trimaran Build Log - 5/20/2009 4:08 PM   
Idealist


 

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Status: offline 		Actually Eric is a mechanical engineer (DI) with a diploma and we had a lot of fun when I called it his "apprenticeship" while we built plugs and hulls.

With my help and advice he shaped his first foamplug(s) and laminated the first glass and carbon parts.
Working in the IT-business currently, it was a big pleasure for him to be able to really work with his hands.

He was very good at that and learned very fast too.

-

I´m looking forward to see a lot more pics and to get the final weights from you.

Actually I wouldn´t mix up Mk.VII and Mk.VIII hulls.
Different design kriterias!
But IF you want to do that, Mk.VIII floats for a Mk.VII mainhull would make more work, but also more sense.
IMHO - Hohohohoho! I´ve never felt "humble" in any way -...-




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RE: Nightmare MKVII Trimaran Build Log - 5/22/2009 12:21 PM   
TBK


 

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Status: offline 		Got the carbon fiber xbeams done. Some photos below. Not surprising that they are stronger and lighter than the glass beams. They come in at 4.5 ozs where as the glass beams come in at 6.5 ozs. Still waiting for the sail winch to arrive so I can bond up the main hull. Hopefully it will arrive today as promised. I will be finishing up the floats tonight and priming the floats and xbeams for paint over the weekend. They will need to be painted as I used epoxy resin which can be affected by sunlight UV. The advantage is that epoxy is stronger and lighter overall, meaning you need to use less resin.

Idealist
I will probably end up making one complete carbon fiber MKVIII eventually. I will just make all the parts for the MKVII and MKVIII interchangeable so I can get parts of it sailing sooner until I have made all the pieces. I will take your advice and start with a mould for the floats. Even though I need to make two sets of shells there are no real internals and these will go together very quickly, where as the main hull needs servos, winches, finbox, rudder log  etc. More time and money. The new float design does provide a lot more bouyancy up front which should to help to further alleviate any tendency to pitchpole.

TBK

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RE: Nightmare MKVII Trimaran Build Log - 5/22/2009 1:44 PM   
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Moulds for the Mini40 Mk.VIII floats are a good decision!
Female or male?

And maybe we have to shift this whole project/enterprise to a bigger size now.
Building smaller and smaller is really getting rediculous.


20ft., 30 ft. and 40ft. -
or should I shift it to www.boatdesign.net?

Any other good "full size" forums for Trimarans?

idealist



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RE: Nightmare MKVII Trimaran Build Log - 5/22/2009 2:15 PM   
TBK


 

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I'd build male moulds the same as I did for the MKVII. They are good enough for a small number of reproductions, but do require a lot more finishing. I printed the plans for that little 65RG tri that you collaborated on.  Quite a neat little package that I may give a try, at least it will fit through my paio doors fully rigged. I can steal the rig off my USOM. It might be a great fun boat for my young son to use. As far as scaling up to full size I'm not sure what route you would want to go with that.

TBK

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RE: Nightmare MKVII Trimaran Build Log - 5/22/2009 2:52 PM   
Idealist


 

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What route? - *Hahaha* - well - round the globe, of course! - what did you think of?

Just need to handle the "financial issues" - like finding a sponsor or playing lottery?
Or find a rich widdow?

no bankrobbery intended -...- *PRUAHAHAHA!*

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RE: Nightmare MKVII Trimaran Build Log - 5/25/2009 11:33 AM   
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Status: offline 		Hey guys - my build has started in kuwait! have the hulls ready for glassing but still waiting on the epoxy and wax to arrive.

Just felt that it has been too long since I've said Thanks and absolutely fantastic work!



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RE: Nightmare MKVII Trimaran Build Log - 5/25/2009 11:55 AM   
Idealist


 

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It is never too late to say thanks - and thank you for the compliment!

Over the past 9 years I had been in contact with about 250 rc-modelbuilders all over the globe -
with a special interest in rc-multihulls.

Most of them asked for help and/or advice.

Some of these got angry on me, because I was unable to give them "comfortable truths".
Some of them even blamed me, because I was unable to find a cheaper, easier and faster way to get a good rc-multihull.

Only five or six out of this bunch of approximately 250 persons had knowledge, which was of help for me -
or at least only these five or six where willing to share their "higher knowledge" .

And finally I was able to find these two "very valueable persons" here in this international forum: TBK and Siri!
With the help of them these buildlogs have been done.

And hopefully your own build will reflect their attitude and you will share your own experiences in the future for free as well.
Good luck for you and your boat!

PS: Untill today you are still No.1 for the whole arabian area - a pioneer!

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RE: Nightmare MKVII Trimaran Build Log - 5/25/2009 3:14 PM   
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That's crazy!

Will do my best to continue the culture and helpout!

I've attached the last pics session, I was lucky to have been able to laser-cut the initial template sections directly from autocad, a bit lazy but allowed me to get started fast.

I've been in a bottleneck for 4 weeks now as I'm having a hard time finding the right type of epoxy locally, and the foreign orders i've made havent yet arrived, am considering getting some of the fast dry stuff they sell here and getting on with it. Also i'm not sure if i need the filler as i'm gonna try a balsa hull with a layer of 2oz as i'd like to be able to still see the balsa when it's all done.

Thanks again,

NS

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< Message edited by nasersultan -- 5/25/2009 3:28 PM >

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RE: Nightmare MKVII Trimaran Build Log - 5/25/2009 5:53 PM   
TBK


 

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Except for the lack of material, it looks like you are making progress on your build. Very nice job with the building board and templates. Laser cutting sure beats the heck out of using an old fashioned scroll saw. From your message I presume that you are going to be making a "one-off" glass over balsa boat and that you don't plan on painting it but leaving the woodgrain of the balsa show through. Here a couple of things that you will then need to consider:

1) If you are using an epoxy resin, then make sure that it is UV stabilized. Most epoxies aren't and they can breakdown in exposure to sunlight - i.e they go "yellow" and become brittle. It may be better to use a polyester resin instead as they are much more UV resistant. Or you can apply a UV resistant clear coat over the epoxy.

2) Whatever resin you use, make sure it has a "working time" of at least 20 minutes or so. That way you won't find yourself trying to rush through the glassing job. There is nothing worse that having the resin start to setup before you have finished. Expoy resins are usually a consistent mix 5:1 down to 1:1 depending on the brand. Adding more hardner than recommended doesn't speed up the curing process. With polyester type resins adding additional hardner will speed up the curing process, but it adds more heat (exothermic reaction) so be careful. Too much heat willl result in cracking. Polyester resins can be pigmented or a gel coat can be sprayed on instead on painting. That does not work with epoxies.

3) If you are very careful when laying out all the planking, so that you don't create any "high" or "low" spots (that can't be sanded out" then you should be able to fair and sand the hull smooth and true. In that case you won't need to use any filler additives. You will also need to consider how you plan to join the upper and lower halves of each hull together. You'll need to insure that the center seam is tight, as it will show through. Not impossible to do, just need to use a lot of care. Instead of glassing each section before it is joined, consider finishing and joining top and bottom sections of both the main and float hulls, then glassing them each as one piece. That way you won't need to "seam seal" the center joint separately. That would reduce the overall weight as well.

Good luck with your continued progress. keep postiing photos as you go along. You can never have enough pictures.

Well I've almost completed all the building on the carbon fiber boat. Just some support gussets under the xbeams left to fabricate and she will be ready for final prep and paint. The completed boat, less batteries and rig weighs just 4 lbs, 8 ozs. Adding my rig  and she comes in at 5 lbs 9 ozs.  Just a little shy of my goal of 5.5 lbs but pretty light nevertheless. This build went quite quickly as I learned a great deal from the glass build and making reusable templates made the fit out very easy. I'll post some photos of the assembled boat, prior to paint.

TBK

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RE: Nightmare MKVII Trimaran Build Log - 5/26/2009 12:26 PM   
TBK


 

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Status: offline 		Here are some photos of the almost completed carbon fiber boat. Just need to add the gussets under the beams and trim off the ends. I will then begin to prep the boat for final painting and finishing. It will be a royal blue , white and silver similar in design to the glass boat. It will have a matching blue trimmed set of sails. I'll post more photos once I get some color on the boat.

TBK

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RE: Nightmare MKVII Trimaran Build Log - 5/31/2009 10:04 AM   
Idealist


 

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Just like me, you are in the range of a TEACHER by now!
Or should I say: "Master degree of RC-Multihull-Builder" approved?!

Paintjob completed?
Ready to give us some final weights?

And don´t think I am gone - I just leaned back for some time and enjoyed what I see here!

Idealist

PS: Regarding the sterns of the floats: It would be better to have less than 90 degrees there -...-

< Message edited by Idealist -- 5/31/2009 10:06 AM >

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RE: Nightmare MKVII Trimaran Build Log - 6/1/2009 12:43 PM   
TBK


 

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Idealist

Haven't had any time to do any work (relatives visiting) on the boat so not much to show. I will be able to get started again today. Final weight with batteries and rig is 5lbs, 2ozs which is not too bad. It will go up slightly once it's painted. Again it's still "overbuilt" but I won't be worrying about anything breaking. Again the pictures look decieving. The sterns on the floats are actually angled at about 80 degrees. My other boat had them at 70 degress, so I wanted this one to be a little different.

TBK



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RE: Nightmare MKVII Trimaran Build Log - 6/1/2009 1:25 PM   
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Status: offline 		Dear All,
long time no see, was full busy with work.

Dear TBK, we say in Turkish " Eline Saglik" means "good work, well done".

Dear Ernst, can't wait to start with m construction, perhabs in July&August.

By for now.


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RE: Nightmare MKVII Trimaran Build Log - 6/1/2009 11:38 PM   
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Hey Erns't , I was considering building my hull moulds split at transom to enable me to bring the transom angle back to around 70 degrees, was thinking of aesthetics mainly but is there a design/ performance reason for angling sterns back??.

Cheers

Gary



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RE: Nightmare MKVII Trimaran Build Log - 6/2/2009 10:04 AM   
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Hey Deamwakes,
it´s not only because of aesthetics, but also clear waterflow as soon as your boatspeed increases past theoretical hullspeed!
(squareroot of waterlinelength in meter x 2,54 (knots) or x 4,5 (kmh).)

What worked best for me - and what I also suggested to Phanchita (Siri) - is 1:2 -> 
If a float stern is 55 mm high, it should be 27.5mm shorter at decklevel. For the mainhull it would be 92mm high - therefore 46 mm shorter at decklevel.
This leaves still enough space for the ruddermounting and aftward crossbar.

For building (shaping) the hulls it is better, to leave the sterns vertical, untill laminating/sanding is completed and
then cut the final stern angle at the end of the process, just before you start to build the female moulds.
This gives you the desired advantage to leave the stern of the hulls open untill hull shells are bonded together.
Also sharp sterns are no problem this way.

Idealist



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RE: Nightmare MKVII Trimaran Build Log - 6/2/2009 1:53 PM   
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Hey Idealist,

I had been giving a bit of thought to this hydronamic issue and appreciate your suggestions..one thing that bothers though is , I understand in full size multi's that weigh tens of tonnes, this hullspeed/waterflow problem exists...I have spent many an hour on 30 tonne cats  watching water get sucked around and backwashing the transom...however I was having trouble relating this to a multi at this build size...the scale / weight thing goes right out the window and I was picking the floats were so light as to not really dig in and suck down.

Other thing I have noted is very few of the 65ft Tri's running in France seem to have much in the way of transom angle 

Still, I built the float plug with a view to fitting another frame internally at the desired transom angle and then slicing off the unwanted portions, does mean building a hull mould split at the transom...a little more work creation going on with that idea...so for now I will take it into consideration.

Cheers..Gary 



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RE: Nightmare MKVII Trimaran Build Log - 6/2/2009 2:29 PM   
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quote:

ORIGINAL: dreamwakes

I had been giving a bit of thought to this hydronamic issue and appreciate your suggestions..one thing that bothers though is , I understand in full size multi's that weigh tens of tonnes, this hullspeed/waterflow problem exists...I have spent many an hour on 30 tonne cats  watching water get sucked around and backwashing the transom...however I was having trouble relating this to a multi at this build size...the scale / weight thing goes right out the window and I was picking the floats were so light as to not really dig in and suck down.




Dreamwakes

Regarding the weights:
Per the rules in the ORMA-60-Class the floats have to have 300% volume compared to overall boatweight due to safetyreasons.

This means boats of an average weight of 5 tone need to have floats of about 15m3.
The reason for this is not the WEIGHT of the hulls/floats, but the PRESSURE implied to them under sail.

I built the "Nightmare Mk.I" in 2000 at a weight of 2.2 kgs ready-to-sail, but it was calculated for 2.5kgs in the beginning -
-  therefore the floatvolume had to be 7500cm3.

Others tried to build it to that weight, but came out with 3.00 kgs. - Therefore the floats only had 250%, which was too little float volume.
The boats where too nervous to sail and custmers blamed ME for "wrong design" -...-
- while THEY had built too heavy - allthough I had told them in the early buildingstages, that LOW WEIGHT is a very vital factor.
Also in terms of higher waterresistance, cause a heavier boat would of course also dive deeper into the water and
the implied FORCE-VECTORS of course also would be different -> more forward, than on a full size 60ft Trimaran.
Therefore the mast AND the centerboard needed to be moved aftward 1/12 of boatlenght - 100mm.

After literally hunderds of hours of "useless" lessons via email - writing tentousands of words to them personally and also in several different forums,
About in 2003 I had to accept it was too difficult for most builders.

Therefore I designed the "Nightmare Mk.VII" for an overall weight of 3.00 kgs + and floats of 7500cm3 -
- later even of 9000cm3, which caused bow heights of 130mm.

Then "they" blamed me for "blunt hulls" -...- blablabla -...-
Now these days some germans are able to build a complete Mini40 Trimaran with 2.00 kgs ready-to-sail,
using female moulds, vaccuum bagging with epoxy/carbon - but I have been banned from this german forum -
as my answers where considered "inadequate".

I´m tired of this after 9 years of trying to educate literally hundreds of rc-multihull-builders worldwide.
But still I have confidence, that there are SOME out there who CAN make it.
Are you one of them?

In fact I could have written two to three books by now about rc-multihull-building and design as well - right? 



< Message edited by Idealist -- 6/2/2009 2:36 PM >

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(in reply to dreamwakes)
       Post #: 174

RE: Nightmare MKVII Trimaran Build Log - 6/6/2009 11:18 AM   
dreamwakes


 

Posts: 166
Score: 100
Joined: 8/2/2007
Last Login: 11/19/2009
From: Auckland, NEW ZEALAND
Status: offline 		Idealist, 10 years of dedication to the multi cause ...what drives you??, is the mini 40 class big in Vienna, which country's in Europe have embraced the Mini40 class??.

Tbk, I was curious as to what the difficulty level is when you need to re rig the sheets...( with turning blocks in the bow and midships)..can you access these, do you use a continuous sheet system with elastic keeping the tension on the lines?.

I ask as I am thinking about how I can make this work in my hull..I would appreciate some advice on this subject.

Cheers

Gary 

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(in reply to Idealist)
       Post #: 175

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