demountable catamaran for the caribbean and south pacific

brian eiland · Aug 6, 2016

https://sites.google.com/a/hucke-media.de/maram36/home---english

On this site we shortly introduce the cruiser catamaran "MARAM" designed by the ingenious constuctor Heinz-Jürgen Sass.

Because we want to buy a bigger boat, we sell our Maram. This catamaran is easy, fast and comfortable. Se sails very agile, and sails very close hauled to the wind. This boat is very seaworthy and has a great range through her high average speed.

She can sail in even at less than 80 cm of shallow water. Sailing before the wind even in only 60 cm water she still remains controllable. The daggerboards are "kick-up" type, the rudder can be lifted vertically.

Despite her sporting character up to 8 people can sleep, there are two double bunks an 4 single berths. Galley with oven, refrigerator, solar panels, navigation, radar, etc.

We have done significant improvements to the rig, comfort and base. So her equipment is up-to-date.

magentawave · Aug 7, 2016

Yeah, I saw that later and here's a line drawing of the kickup daggerboards.
https://sites.google.com/a/hucke-media.de/maram36/startseite/katamaran-maram-ii

brian eiland · Aug 7, 2016

magentawave said: ↑

Yeah, I saw that later and here's a line drawing of the kickup daggerboards.
https://sites.google.com/a/hucke-media.de/maram36/startseite/katamaran-maram-ii
Click to expand...

Could you find a dwg of the sailplan?
I find it interesting that the mast appears to be mounted quite far aft.

magentawave · Aug 8, 2016

brian eiland said: ↑

Could you find a dwg of the sailplan?
I find it interesting that the mast appears to be mounted quite far aft.
Click to expand...

I looked and couldn't find a line drawing of the Maram 36 rig. There's not much out there about that design.

The early Prouts had the mast shoved aft too. Anyone know what the thinking was back then for moving the rig aft like that?

tane · Aug 8, 2016

the thinking afa I remeber was
1 to get a lifting component from the foresail because of the big angle to the vertical of the forestay &
2 to improve windward performance with the larger foresail
3 lighten the pressure on the leebow

the Prouts were fairly extreme in this, but Newick had it too with masts at 50% length & not to forget Crowther with Twiggy

brian eiland · Aug 8, 2016

Prout Rig Problems

...several 'less than optimal' features...

brian eiland said: ↑

.....
For a moment look at the profile drawing of my rig and picture it as though the mast was standing straight up vertically with its masthead in the same location as mine now is. Contrary to Tom’s statement, my forestays are really no longer than a conventional sloop rig, in fact they are likely shorter. And his comments about the angles between the backstay & the mast and the forestay & the mast are not quite correct. In reality it’s the horizontal (not vertical) component of the tension forces in these two stays that determines the ability of the rig to resist sag in the forestay……my masthead backstay has a more advantageous (rearward pulling) angle than does my forestay pulling forward.

Interestingly, this phenomenon was probably most detrimental to the Prout mast-aft rig. Their short vertical mast at the aft position resulted in a highly sloped forestay that was both too long for the rig’s overall height, and it could over-exert a forward pulling force on the masthead that was indefensible by the shallow-angled backstays…..result, big time sag, sails too full. This rig had other problems as well….not an example of a successful mast-aft rig, but a case study in some things to avoid. (added note: the Prout cats were a very open design down below with insufficient bulkheading. This is combination with there early style resin construction provided less than optimum 'stiff support structure' for their rigs)

Most of the mast-aft rig experiments I can find thus far, have all moved the mast to the very stern of the vessel. Thus they are unable to maintain adequate headstay tension. Without this tension our headstays sag with increasing winds, our sails become fuller rather than flatter, which is exactly what we do not want, and thus the poor performance of previous experiments. With sag they all had to continually re-adjust their sails, and thus they were all seen as problematic. I think I have solved this problem. The key to proper forestay tension is proper backstay tension! First look at my masthead. The single backstay at this location is actually pulling aft at a more favorable angle than on most all other sloop rigs. This might suggest that we could decrease the tension load of this stay, but wait, lets keep it tight in order to maintain the mizzen’s leading edge shape as well. Hard to see on the website drawings, but the bottom end of this backstay is attached to the frame member of the vessel that supports the mast…the backstay’s tension upward is countered by the mast’s compression load downward…….less strength required from the frame structure, and it cancels out the dependency of this backstay’s tension on the stiffness of the aft sections of the hull structure. (The frame structure itself is also a major bulkhead of the vessel). At the hounds is where we really load things up. We have the inner forestay tension we wish to maintain, and we have the significant forward push of the aft jumper as well. Lets employ two quasi-conventional pieces of rigging: 1) the two forward facing ‘baby’ jumper struts are rigged in such a manner that both jumper stays are always sharing the load rather than allowing one to go slack, 2) the lower backstay from this hound location is split into two legs in a geometry that promotes both legs are always sharing the load rather than the normal situation with a slack leeward stay. All the rigging is working full time, which imposes less load to any single member and less load to their attachment points. Note I have 3 backstays working full time. The x-wide staying base of a multihull allows for x-wide spreaders (note no overlapping genoa) thus lower compression loads from the shrouds…..and they in turn are anchored to this same cross frame member that supports the mast.

My mast will experience lots of compression loading, particularly in the lower sections, so the key is to keep the mast in column. Heavier wall sections are not necessarily the answer. Keep it in column. This is where subtle changes to the geometry of the sailplan could produce the most optimum form……it might predict factors such as the optimum overall height, spreader placement, jumper strut lengths, attachment points and methods, etc. This is where I believe the computer and a finite element analysis could be very helpful in analyzing all of the rigging loads as a result of modifying any single link and determining the load requirements for all the parts. I am seeking funds for this comprehensive study so we get it right the first time out….and I would love to have someone with Tom’s analytical capabilities involved, including Tom himself.
Click to expand...

catsketcher · Aug 8, 2016

Much of the time you will find that a mast is placed where it is because of structure. The Twiggy was a boat I owned and lived on. Lock drew the rig far back because he wanted to get the Centre of effort of the rig far aft. He also got the mast at the front of the cockpit where a short handed crew could easily adjust all the controls.

I don't think that racing has every shown a large jib small main boat to be faster (unless it uses unrated overlap like the IOR boats of the S and S style - one boat was supposed to have won a race without its main). If you look at fast boats then they all have relatively large mains. The faster they go the larger the proportion of the mainsail until like C class and AC boats they only use headsails in light winds and downwind.

I think the Maram probably has the mast situated on a bulkhead. Usually bulkheads are spaced pretty far apart so after the designer went in that spiral they do the eventual compromise of all different factors led to the mast ending up in that position.

magentawave · Aug 9, 2016

catsketcher said: ↑

Much of the time you will find that a mast is placed where it is because of structure. The Twiggy was a boat I owned and lived on. Lock drew the rig far back because he wanted to get the Centre of effort of the rig far aft. He also got the mast at the front of the cockpit where a short handed crew could easily adjust all the controls.

I don't think that racing has every shown a large jib small main boat to be faster (unless it uses unrated overlap like the IOR boats of the S and S style - one boat was supposed to have won a race without its main). If you look at fast boats then they all have relatively large mains. The faster they go the larger the proportion of the mainsail until like C class and AC boats they only use headsails in light winds and downwind.

I think the Maram probably has the mast situated on a bulkhead. Usually bulkheads are spaced pretty far apart so after the designer went in that spiral they do the eventual compromise of all different factors led to the mast ending up in that position.
Click to expand...

Twiggy, what a cool design. It was Crowthers answer to Newicks Val, right? Could you sail your Twiggy under mainsail only or was it weird like that?

catsketcher · Aug 9, 2016

Yes it was Lock's Val. I interviewed Dick a couple of times and when I saw him in person we talked Twiggys. He remembers squeezing Lock into his Herreshoff canoe and paddling out to Third Turtle at the end of the 76 OSTAR the morning that Mike Birch came in. Lock was there hoping to welcome Spirit of America (which he built as well as designed) but she retired. Dick said as he paddled them both around he could see Lock thinking.

When I asked Lock about the boat he said as he was being paddled around he thought "I can design a boat that will beat that". Sadly I don't know of a Twiggy and a Val ever going up against each other.

The Twiggy could sail fine with only a main up. You just couldn't sheet the main in tight. I could even tack her but you had to be pretty smooth and ready to dump main as soon as the rudder thought about giving way.

magentawave · Aug 10, 2016

That's a great story. I was surprised to read that you lived on your Twiggy because I keep thinking how it would be to live on a tiny Val. But I just refreshed my memory by looking at images of the Twiggy for the first time in years and it looks like it's a lot more roomy than the Val. I bet she was a joy to sail, right?

catsketcher · Aug 10, 2016

Good sea boat with full head room. About 15% of the usable interior room of my modest 38ft cat but still we cruised her with two adults and a baby for 18 months.

brian eiland · Aug 10, 2016

Surprising what we can made-do with in our youth

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demountable catamaran for the caribbean and south pacific

brian eiland Senior Member

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tane Senior Member

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