Idea 850

Idea 850 is a fast paced cruiser-racer: wide beam , generous sailplan and light displacement make her a really fast boat; she can be built in wood & epoxy strip planking for an uncompromised quality and strength. This small rocket packs also huge interiors for 5-6 people, and every aspect of building is highly detailed in the drawings.




Idea 850 Studyplans: sailplan

Idea 850 bill of materials

Idea 850 Studyplans: deck gear

Idea 850 Studyplans: structure

LOA: 9,70 m (fixed bowsprit included) Righting Moment at 30° :   2550 kgm   
L hull: 8,53 m AVS (angle of vanishing stability) : 124°
Maximum Beam: 3,18 m Sail area (regatta version): 51 m2,  43.3 for cruise version
Waterline beam : 2,64 m Main sail: 34 m2 (regatta) ,  28,4 (cruise)
Draft : 1,90 m Olympic jib: 17 m2  (regatta), 14.9 m2 (cruise)
Keel ballast: 700 kg total (600 kg on lead bulb) gennaker: 55 m2 (fractional),  83 m2  (masthead)
Air draft: 13.28 m form waterline engine: 20 HP inboard diesel or electric, saildrive or shaft line transmission
Light displacement : 2150 kg        interiors:  5+1 berths, separate toilet
Design displacement: 2750 kg
Maximum displacment : 3150 kg Plans can be purchased here : Nautikit order page   Plans price: € 800,00

Idea 850 is the development of the concept of Idea 19 and Idea 21 on a bigger scale, so she’s basically an offshore fast paced cruiser, that can be tuned as a racer with some attention to keep her light during the building process (weight savings  modifications are described in plans**);


Hull: hull features a chine on two thirds of her length, to gain the maximum shape stability in the first 30 degrees of heeling, a wide but not humongous beam, flat transom sections to have a good planing attitude downwind and reaching,  and very powerful U shaped section at the bow ; the stability curve points out a high righting moment to cope with the real generous sailplan , and a more than  good 124° of AVS (angle of Vanishing Stability)

building process:  Hull has to be build with strip planking system in wood and epoxy resin, on a scaffold made by cheap wood temporary frames, hull is internally and externally laminated with a layer of biaxial glass,  then turned on her cradles, all the other wooden structures (stringers, stempost-backbone, bulkheads and floors) will be bonded and laminated internally; all the cabin, deck and cockpit surfaces are made in marine grade plywood built with “stitch & glue” system.

keel: fixed, with a 600 kg lead bulb bolted on a NACA profiled welded steel finkeel , bolted on solid wood floors with 20 high strength steel bolts ; if required a shallow draft keel solution will be included in plans, standard draft is 1,90 m at 2750 kg displacement

rudders and steering system:  double NACA shaped rudders transom hung with a central tiller , drawings are highly detailed to built a reliable and strong steering system.

Sailplan: two swept spreaders mast stepped on deck, aluminum alloy or carbon , two versions of sailplan will be detailed on plans :

-Sport Cruising :  moderate roach on mainsail, olympic jib,  code zero on furler on fixed (optional) bowsprit), fractional gennaker  , single backstay, babystay and not structural runners for heavy weather

-Regatta:   square top full battened mainsail, retractable alloy or carbon bowsprit that can be pivoted, olympic jib with 3d system sheeting point , code zero on bowsprit, masthead and fractional gennaker  , double backstay and runners

engine : inboard diesel or electric engine, saildrive or shaft transmission, up to 20 HP for diesel engine ; drawings detail the engine fitting and related systems

on board living:  boat is quite roomy both in the cockpit and in the cabin, interiors features a separate toilet room, 5 fixed berth and a deployable one, with all berths of 1,90 m or more length, a charting table with navigation instruments and control panels, a L shaped galley area and a lot for space for lockers and storage. Internal height is 1,85 meters .  Liferaft can be stored in a dedicated box on the transom, sheltered and ready to be launched if needed.  Freshwater tank :100 liters or more , fuel tank: 40 liters , holding tank for WC :  30 liters.

building plans : they’re made of 26 drawings, covering all the aspects of boat building, including interiors and systems (fuel, freshwater, Wc plumbing, electric, fuel) and a 20 pages booklets with the advised building sequence, tips and tricks, and the complete deck gear commercial specifications























** “pure racing” version weight savings: these extra notes are available upon request with plans: professional skill on composite materials and vacuum bagging process are required to built the boat in this version: several internal structures are made by glass sandwich elements, laminated and vacuum bagged with epoxy , instead of marine plywood and solid wood, interiors panel  and floorings are in light composite construction, rudders are foam cored built and so on; all the weight savings described in these notes lead to an approximately 300 kg lighter boat with minimalist interiors, perfectly suited for an offshore racing campaign.