Rapido 60

When the Rapido 60 trimaran first appeared, I figured it was some kind of a joke. The styling recalled an F27 from 20 years ago. I teased that they owed Ian royalties. It’s beam overall was just over 38’, which some of mine, and most modern 40’ + trimarans, equal.  My GS 60 beam overall, from 25 years ago, in E-glass, was 44.5’. Everybody knows that when you push a multi, wide is what keeps you right side up. So making it not wide had to be something to push onto the unsuspecting, right?

Almost all the pictures I saw of them had the crazy camouflage paint so it was never clear what was going on. I figured that they were not serious and didn’t think much more about them.
It was just pointed out to me that the R60s don’t have continuous mainstrength beams. Blew me away. Followers of this over the years have seen the importance of continuous fibers, fiber orientation, co-curing of mission-critical parts, not forcing composites into sharp turns…..
And here is one design that seems to ignore all that. What gives?
And that explains the narrow overall beam. That’s the only way to keep the loads down, besides throwing carbon at the problem.

Again, I have always declared that with enough carbon and enough money, one can have almost anything designed. This seems to be a prime example.
If we assume 24,000 lbs sailing weight, and a 12’ cantilever of the beam, then hit it with a shock load on one of the beams. The moment at the root will be something like a quarter million foot pounds. If the bury is 3’, then the load to resist will be some 80,000 lbs.
No wonder it is so heavy. Yes, heavy. 20,000 lbs. lightship. It is all carbon, right? That carbon has some 5 to 7 times the modulus of E-glass. Compare to my GS60 at 13,000 lbs., as designed, in mostly E-glass.
Main point. You can’t beat a continuous D section for the most beam strength and stiffness, the least weight, and least cost to build.
And again, all boats inhabit a place on a continuum between a habitat and a vehicle.
The R60 seems a bit confused.  All the carbon tells me vehicle, but chopping up the lightest, strongest possible connecting beams to get more cabin space is right back to a 1960s Horstman; habitat.
None the less, I’m sure they will sell a lot of them. The owners can “Hey baby, I got a carbon boat.”
I prefer direct, simple solutions to magical ones.

5 thoughts on “Rapido 60”

  1. It was designed to be a 60ft Farrier – to fold in dock – but they skip that later (costs). It explains the narrow beam og that the beams are not in one piece. This is a cruiser – not a racer – so thats ok in this concept – they have interior space as a big factor. But given that – why cant they make the main-hull wider – at the floor level – they will get a lot more useful space – and still light – the main hull will be very easy to plane in speeds anyway.

  2. Horstman’s message in his designs was that thin structures are weaker. Go getting the cross arms opened up to what 3x means less of the load bearing in the narrow as a cost reduction from the standpoint of transfered to this is less carbon.

    His boats weren’t as light as they could have been but when you put them in the class of condo maran they didn’t look that bad in terms of bad windage, and weight.

    From a design standpoint the simple beam running the length of the beam has a real purity in understanding flex etc. With “newer” structural software it maybe possible to design an equivalent socket/bulkhead systems to get the same effect with a wider structure to carry the load reducing carbon requirements.

  3. I’ve wondered that, this approach to demountability seems to add a lot of weight. I’ve seen a similar structural approach taken to Three Little Birds in that case the beam inserted and was retained in a square section carbon support which was heavily laminated into the surrounding structure. I’d guess this is done in a similar way. It looked like it relied on the ring frame/bulkhead it was inserted into to distribute the loads. There is some build photos over at Aquidneck Custom boat builders: http://www.aquidneckcustom.com/shop-log/pt11-project/pt-11-construction-begins

  4. Kurt,

    Why do you always poor-mouth others designs? I read this blog every now and then and I’m confused how you treat others. Like this post nothing to say just “shit design I can do better?” Look at your boats they look like a Volkswagen KdF-Wagen from 1938.

    Performance? Have we seen your boats on big races lately? Any big achivements on 2000 centrury?

    fuck that it that and stop posting shit like this

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