The multihull test! -

Practical Experiment:
With this topic I just want to find out,
if rc-multihulls are the stepchilds in this forum -

  • or if there is a hacker,
    who hates multihull discussions - especially if I - Ernst Zemann - participate in them -…- or if I’m now getting paranoid as well -…-

Proverb from a secret service agent:

I suggest - if this topic remains - to continue the discussion here - William and Ian - and if it disappears, we have to find an other way for free communication. -

Ian Sammis is the US-Producer of the F48-NIGHTMARE. - I
m not producing them anymore - I’m just the designer! -
So if anybody would be interested in this boat - please contct Ian - he is a member of this forum too! -

my picture gallery is still:
and my email adress:
(Petra is my wife - for all curious guys)

Best Wishes, Ernst Zemann

Download Attachment: [ F48 Nightmare 1.jpg]( Nightmare 1.jpg)

Download Attachment: [ F48 Nightmare 2.jpg]( Nightmare 2.jpg)

Professional shipwright - boatbuilder/-designer with 25 years of experience and a special interest in multhulls

Admired the photos. I’ve always wanted to make a Tri. Really. I’ve often thought of attempting to make a really small R/C trimaran with a very tiney rig to deal with proprtionally stronger windspeed to reduce capsize. (I know there have been these discussions before but what the heck its interesting. I say let the ball keep rolling)

I made a really small freesailing trimaran about twenty years ago out of nothing but shaped foam coated with acrylic Artist medium, sticks for cross beams, and glad trashbag sails with scotch tape luff pocket. It was like maybe twenty inches long. the whole thing cost me like maybe two doallars. I remember chasing after it in my dads rowbot. never had more fun. It sailed extreemly well. didn’t tip over once. Lot to be said for steady winds on open water.

Ernst, I have an idea. I am a Design Engineer at Cessna Aircraft…I use CATIA, three dimensional software to design my aircraft parts. I also have a copy of this software at home and have now drawn in the crossbars, crossbar attachment methods, nuts, bolts, etc. But I do not have an accurate representation of the hulls. It would be really interesting to get your NIGHTMARE design completely drawn up in CATIA so that we can look at the whole design from many different viewpoints. What I mean by this is that we can rotate it, flip it upside down and look at the hull design very indepth three dimensioanlly and maybe it will give you ideas for your next design! Another thing I can do with this three dimensional model is do a stress analysis on the crossbar attachments and we can find the best solution for a very stiff boat. All I would need is some actual dimensions of the hulls at every station point.

Ian Sammis
Builder-Nightmare F48 as designed by Ernst Zemann

Hello again! -

Dear John Storrow - Thank’s! - We definitely will keep the ball rolling! -

Dear Hoj and Ian - if I may:
And in cooperation with Ian Sammis and William Hojnacki I will publish all necessary informations, building tips and complete construction plans for several different selfbuilding trimarans - as well as possible future projects for production trimarans - at the current level of design! -

To get an idea of what I’m aiming for - also to answer Ians question about CAD - please have a look at the site of my favorite pesigner:

3D drawings would definitely be GREAT, it’s just the question if it isn’t faster, to simply BUILD the designs and publish their pictures here? - Or use the allready existing renderings of well known naval engineers to communicate ideas? -

The main problem has allways been, how to SIMPLIFY these full size designs to fit for the 1MeterClass or for the F48/Mini40- Class, which is 1.22m long and wide. -
This has been the part of design, where I had to spend most of my time! - For the hulls, the biggest problem where the numbers of cross sections - 10 sections are not enough! - I allways used 12 sections - with 10.0cm/4" space between each! -
For even ligther and slimmer hulls (for strip planking) I have now developed sets of plans with 15 cross sections of only 8.0cm/ 3 1/16" for the F48 and 6.5cm/ 2 3/8" for the 1 Meter class!!! -
This makes sure, even balsaplanks of only 1/32" thickness don’t sag through between the cross sections! (I hope, my english is good enough here?!) -
Sealed with epoxy resin inside and out and only one layer of thinnest glass outside, a float could come down to 0.25-0.3kg - and even semi-experienced modelbuilders can build them! -
And that works for all hulls! -

Download Attachment: [ Drydock F60 - DAYDREAMER.jpg]( F60 - DAYDREAMER.jpg)

Professional shipwright - boatbuilder/-designer with 25 years of experience and a special interest in multhulls

How do you make the cross beams in that shape and make them light? are they molded carbon fiber, or laminated solid wood?

Like on the full scale picture below!-

-I just made 2 curved scale frames out of 3/4" chipwood, covered the top with 1 layer of 1/16" plywood. -
Then I cutted one foam strip 1 x 1", nailed it in the right shape with small nails onto the plywood, resanded the foam a bit - and then glassed it over on three sides. -
After curing I took it off, sanded the lower seems, turned it around and glassed the fourth side (which is the aftward side actually), the radius and the top and bottom sides over! -
In this way, the flanges got 4 layers of 160g/m2 glass - and top and bottom got 8 layers - as it it supposed to be for a 60" model! -
For a F48 tri the foam strip is 3/4" x 3/4" - with 3 layers of 160g/m2 for the flanges and 6 layers therefore for top and bottom. -
If you can scale this complicated shape down for a MultiOne Trimaran with a proper weight and stiffness, is a question of VERY fine craftsmanship! -
I CAN do it, but it doesn’t make sense for ONE single model!!! -

I would prefer, to make a pair of female moulds for F48 and for the 1Meter class - which would only make sense, if at least 10 pairs of crossbars each are needed -…-
I would build the prototype (the plug), make the female mouldings and do TWO pairs for myself - write down any conclusions - and send the molds together with my writeup to Ian Sammis, who would produce the crossbars then for all US-customers -…-

Does this make sense? -

And here comes the MAIN and BASIC QUESTION in again:
How many multihull interested people are there currently at the USA??? -

Votes please:

Ernst Zemann

Download Attachment: [ Setup for doublecurved crossbar moulds.jpg]( for doublecurved crossbar moulds.jpg)

Professional shipwright - boatbuilder/-designer with 25 years of experience and a special interest in multhulls

Ernst: How do I get plans of my Nightmare’s and MKIV Superslim? Building instructions? You say they are available. There is a 12 hour difference from Hawaii so it must be 2:00PM there. Sunday. Goodnight!

William, complete building instructions will be there, as soon as I write them down completely! -
But I would need to know, if they are for experienced builders or beginners! -
For beginners it would be 3-5 times more necessary text to write!!! -
And I don’t think, you need a full set of instructions - or am I wrong? -

Complete linedrawings and buildingplans for your ALL boats could be done, but if you don’t want to reproduce the boats - what do you need all the plans for? - Please explain! -

My idea was, to publish general drawings on the net - and each single cross section for scratchbuilder as well. -
But each and every plan 1:1 scale? -
This would be some 100 - 200 hours of work for me. - For free? -
You need to convince me about that.
Friendly greetings, Ernst

Professional shipwright - boatbuilder/-designer with 25 years of experience and a special interest in multhulls