fast but lightweight cruiser

Hi Gary, you got me noodling around with FreeShip again.

 

Phil, is that a trimaran main hull or a ... monohull?
One thing I found with Freeship, if you have the stern waterline finishing on or below WL, then you won't get any hydrodynamic etc. readouts. Learned the hard way. Maybe it is different for you?
The turn in your bilge below WL is quite an angle; you might find it difficult to build. Cheers.

 

Hi Gary,

A page or so back you commented on having to step over the beam to get inside the boat. What about using Newicks ideas and curving the beam over the top of the cabin. This would give loads of beam/water clearance as well as looking really cool.

Tony

 

Basil, that step over beam was with my earlier (and silly) idea of raking the beam forward from near the cockpit.
Changed my mind, straight beam now - and you'll have to duck under it. Can make an ergonomic hole under there yet still retain structural strength.
But my sailing mate Jacques just phoned from Gisborne (he rode his BMW chair outfit down there for the Kiwi side of family holiday stuff) suggesting why not alter Groucho ... and I've been thinking that over too. But you crawl through under Groucho's beam because that boat is so narrow, low and long, hardly the basis of a cruising main hull. Think it is better to start anew.
Agreed, the Newick arched high beam is an excellent solution.

 

Looks great Gary, as usual...! Where next?

 

Freeship hydrodramatics

Hi Gary,

thats quite easy to solve.

If your bottom line at the transom is under water you have to close the stern, so that no virtual water is running into your hull.

Go the following path:
Mark the last red control lines (representing the transom) to yellow ... open "edge" menu and choose "extrude" . Here you have to extrude the control lines transverse to the centerline, setting a "minus" before the measure and a little larger than the half of the transom.

For example: if your half transom measures 1m wide fill in at transverse: -1,1m.

As soon as the transom is closed, the hydrostatics are active and visible again.

With the same tool you can devellop your decks and cockpit.


I like your designs in general and your Idea with the wingmast catketch and single beam in particular. But that first cruiser deckline is a little to "fat" for my taste, the second (hand drawn scetch) suits me far better. Anyway, a very inspiring new attempt on a lightwheight cruiser. I will follow your thread with great interest. Go on!

What for main numbers and basic scantlings do you have in mind for the new design?

Best Regards, Michel

 

I'm wondering about how close the masts are to each other on post #29. Will the higher apparent wind speeds cause an issue with turbulence? Didn't the proa Sidewinder had that kind of trouble? I kind of like the sketch better too.

 

Thankyou very much Lucky Strike for your corrections with Freeship. Being relatively new to the program I just use it like a line stretching sort of thing until I feel the "right" shape is produced. To do decks and cockpit will be even more fun. Thanks again. Yes, still working on deck "fatness" and curves.
But a dragging transom is something I really don't like ... so the fact that I finish the upper hull and transom above WL, suits me fine.
At the moment hull displacement is around 1.3 tonnes. I'm thinking of 4mm tensioned ply doubled in high load areas - like build the shape, turn it over, then double up in beam, daggerboard and rig and ring frame areas, plus uni directional carbon where needed. The single beam will be a box with air foil framing, tensioned 3 or 4 mm ply skin, carbon in shroud attachment areas, pretty much like a larger Sid.
Cav, I thought/worried the same with the close together masts on Cox's Bay Skimmer (there's only enough gap to let the forward boom swing without fouling leading edge of main mast - in fact I've cut a flat area near its base to allow this) - but there have been no problems at all. Maybe the rotating wing masts clean up the wind flow better than fixed rigs because the boat goes to windward like a witch. Reaching, broad reaching, same.
What is interesting are the wind indicator angles; forward mast is very close to wind, main mast maybe 3-4 degrees freer. There appears to be no disturbance on after rig that we can see. After sail is sheeted in very hard, beating.

 

Should be interesting, obviously close headsails work....Remember though, the apparent wind will be much faster/closer than the skimmer.

 

Very encouraging to hear positive first-hand experience (particularly upwind) with such a rig - thanks.

Is there ANY source of pictures of Bay Skimmer's rig - sailing or otherwise?

Thanks,

 

Here you go. Originally there was a transom rudder setup but I changed that last year to underhung (less turbulence, cleaner wake, just imo) - and got rid of the peeling-in-Auckland-summer black deck, changed to fibre rigging and a few other things.

 

Hi Gary, you are welcome, have fun with freeship!, its a good tool for what you are doing with it.

Nobody likes dragging transoms, because this is the only area where resistance is visible. But sometimes they make sence.

Thanks for the informations, I have a better view now. 1,3t, whouw this is a hot number for a cruiser, but I know that you know what you are doing. . My 30' Racer/Cruiser design has the same displ. in racing mode.

Best Regards, Michel

 

Michel, stop taunting us; let's see your racer cruiser ... and your Freeship expertise. Cheers.

 

I designed my boat a few years ago on paper and pencil, freeship is later.

Husky 9.2 Racer/Cruiser

9.2 x 8.2 x 0.35/2.1m, 950kg light ship, 1300kg racing, <1500kg cruising, sa 58 m² (38m² main, 20m² genoa) upwind with 100% genoa.

200% full length amas, 5mm tortured ply with glas outside and inside + carbon.

Mainhull from 10mm WRC strip in the bottom, 6mm ply sides and deck + glas, doubled to 10mm in high stress areas + carbon. one double bunk (converted setties) , one single in the bow and one permanent seabunk. One main daggerboard, one main rudder and two (very small) in the amas.

Design will be develloped further during building (negative bow and so on).

Boat is designed for offshore races with ~ 600nm distance (north sea, baltic, english channel and north atlantik) or basic cruising for 2 + children.

Sorry for the bad photos

 

Sehr interessant, kollegen.
In many ways similar to my thing ... but different too. Keep us posted with your progress.