Harmony - Technical Profile

  • 29 Jun 2020 19:57
    Reply # 9068099 on 9065486

    .... plus the ability to insert the plywood plates to keep the electrical cable conduits central to stop them banging on the sides of the masts. 

    That happens on Lexia and it drives me nuts !  So much so that one day I will drill holes in the mast and inject expanding foam ... 

  • 29 Jun 2020 19:18
    Reply # 9067999 on 9065486


      Thanks!  That's great info.  Gives me an alternative to consider.  I was considering an aluminum flagpole but shipping is an issue.  The ability to repair a bent section is definitely a plus. 


  • 29 Jun 2020 12:57
    Reply # 9067267 on 9065486

    Hi Brian,

    of three outside tubes, No1 (bottom one) and No2 (middle) have spigots (see the first photo) of about 0.5 m length so that upper section snugly fits over. There is always some gap, though, so at assembly the spigot is smeared with epoxy glue. While glue is still working, each upper section is riveted to the lower section's spigot with aluminium rivets. Originally, we tried SS bolts, but electrical corrosion got better of us, so we switched to Alu rivets and that works fine.

    Nothing is welded, and if need be, can be disassembled and replaced. 

    Actually, our cruising experience does include an incident in which top section of our mainmast was broken. The stump was pulled out of the boat, top section removed (epoxy does not stick too much to Alu, it is only there as a filler. New section was ordered and put in it's place (as per method above) and mast re-stepped.

    The second photo shows bunch of tubes (yes, we assembled the masts in our front-yard).

    At each top-of spigot, we inserted a plywood plate with holes for plastic conduit for wires. These barriers keep the wires centred (so not to bang in a seaway) and also act as stiffeners (to the point) like in a bamboo. See the third photo.

    Inner bottom tube snugly fits to outer bottom tube, and the assembly is held by through-bolts for fittings (cleats) and by a bottom (flush with skin surface) screws that hold the bottom barrier. See the fourth photo.

    The fifth photo shows two masts ready for stepping (this in the boatyard) and the last photo illustrates a phase in mast stepping.

    Hope this helps...



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  • 29 Jun 2020 11:28
    Reply # 9067066 on 9065486

    Thank you for sharing.  It is a great looking rig.  I would be interested in knowing more about how you constructed your masts.  Are the tubes welded together?  Do you have a sketch oand  pictureu uy could share?

  • 29 Jun 2020 01:40
    Reply # 9066563 on 9065486

    Thanks for taking the time to detail Harmony's technical aspects and your decisions to employ them.  This sort of information is invaluable for our database of experience.

  • 28 Jun 2020 14:41
    Message # 9065486

    Hi All,

    since our intro-post as new members, has already attracted intense technical scrutiny, we hought that it would be useful to present a technical profile of our yacht Harmony, so that our ideas and their implementations are better understood.

    Harmony is Bruce Roberts Spray 33 design, meaning 33 ft on deck, however LWL is only about 26ft where LOA is 37ft (we shortened original bow-sprit and added small davits). This makes her short when sailing and long when in marina (but just right when on anchor). Beam is 12 ft and maximum beam is practically mid-ship. Rather blunt nose, a lot of volume in the bow. Full-length keel, draws about 4ft. For design details, please check www.bruceroberts.com.

    Harmony is built in steel and nominal displacement is about 10.5 ton, while in cruising mode it easily reaches over 12 ton. That makes her extra heavy. Balast is about 3 ton but this has to be understood in context of steel boat build - keel is heavy metal indeed and should be considered part of balast, so we think that proper balast ratio for any sort of calculation should be considered as 30% in cruising trim.

    We designed the junk rig for her. We followed ideas and instructions from PJR book while adding several demands to the solution: we wanted a great deal of redundancy so we decided to have 2 masts with 2 identical sails with all battens of the same length all booms and yards of the same design so to be interchangeable. The result was a schooner-rigged boat (main mast is 0.7 m longer than foremast), main sail is set a bit higher (to clear the dog-house). Main mast is vertical (12 m, 10 m above deck), while foremast (11.3 m, 9.8 m above deck) has about 2 degrees forward rake. This forward rake with greater balance of the foresail (about 15%) allows minimal clearance between the sails. Minimal is in this example less than PJR recommends, so initially we rigged "hybrid" double-sheets to foresail, but soon reverted them to single sheets. Distance between masts is 3.6 m as is length of all battens and yards and booms. Yes, foresail sheets catch mainsail luff every so often, on average once every 3-4 gybes, which for our typical cruising style means once a day. We accept that. Lately, we are thinking of reverting back to double sheets, for different reasons, but we'll see what happens.

    Each sail has an area of 275 square feet, professional made (to our specifications and design) of Dacron. We reach our target cruising speed (5 knots) in about 12 knots wind. Downwind and reach, that is. At 18 knots we start reefing. At about 25 knots we are down two-thirds and above 30 knots we switch to survival. Maximum sailing speed (excluding current) we keep below 7 knots. Actually, 6-6.5 knots is a red flag for us to start taking power of the boat.

    Masts are made of aluminium tubes, top 2/3 length is tapered. OD at partners is 206 mm. Each mast consists of 5 tubes: 3 outside tubes (top 2 carry the taper) where bottom tube is doubled with another inside it (hence no tapper) and than, trippled with another short tube (1m) at partners. Each tube has walls 6 mm thick. Outside tubes are anodised. Main mast weighs 125 kg while foremast is 118 kg. All this was made for us by Goldspar (why? because their quote for the masts were within a whisker of price of wood to build the masts (Sydney prices, 2009)). Goldspar made the tubes. Assembly, dressing, cutting, drilling, wiring, all fit out we did ourselves.

    Sails are, by necessity of rather high aspect ratio, 2.15, still within PJR recommendations. Consequently, relatively smaller area is in head panels and sail roll angle is higher. Both, in our view, are adding to safety.

    Sheets are 5-part, halyards are 3-part. We have arrangement where all sheets and halyards can be supported with 2 small self-tailing winches, but rarely use them (mostly if we want to do "short" gybe).

    One person does all handling. Exceptions to this: in safe conditions we raise sails together (one person is sweating the halyard at the mast) - it is faster and more fun (in iffy conditions, G can raise sails by himself while M needs a winch for last 2-3 panels). Also, reefing we do together, to keep both people aware of changing conditions, but it is really one person work amount. 

    When there is no wind (i.e. less than 4 knots, we need at leat 5-6 to keep 1.8-2 knots boat speed or we loose steerageway) or if we need to go against weather (why?), we motor. To that end we have 38Hp Nanni diesel. We carry 250l of fuel nominally, which gives us about 400 Nm autonomy, but can load up to total of 400L which gives us about 650Nm autonomy.

    Presently we have "only" 5 anchors, our main one is Rocna 20, while supporting ones are Rocna 15, and Fortress FX-23. Main rode is 55 m chain (L-grade, 10mm) and that can be extended with 2x 50m lengths of 18mm 3-strand nylon.

    We carry 2 drogues (Burke sea-brake) and a parachute sea-anchor. Neither we used in anger (yet) and let's hope it stays that way.

    We carry 550L of water in 3 tanks. have 500 Ah + 100 Ah battery banks and 240W + 100 W solar panels. GME chart plotter, iPad chart plotter, iPhone chart plotter, MacBook chart plotter, 2 more GPSs. No sextant. VHF with AIS receiver, separate AIS transponder, handheld VHF in a grab-bag. Fridge. Inverter. Washing machine. Computers. Composting toilet. Gas-powered stove and oven.

    Harmony was launched in 2008, made a sailboat in 2009, made a home in 2010 and sailed out of confines of Sydney Harbour in 2015.

    Our dinghy, not to be forgotten, Horsea, we made from plywood to John Welsford "Sherpa" design (sailing version) with some amendments: added 5 independent sealed compartments, added 4 cm polyurethane padding to sides, added basic 12V wiring, equiped it as a mini rescue boat. As of present we do not carry life-raft but that might change due to regulations that could be imposed upon us.

    We hope that you find above description interesting.

    Gordon and Myra Koch

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