First Boat Design looking for feedback!

Discussion in 'Boat Design' started by LTDboatdesign, Nov 2, 2010.

  1. LTDboatdesign
    Joined: Oct 2010
    Posts: 23
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    Location: Bainbridge Island WA

    LTDboatdesign Junior Member

    Hey everybody,

    I have reached the point in my design that I am ready to show and tell. I have designed the boat to be a cruiser. Not looking to race her. I just want it to be easy to steer, a comfortable sea motion and big enough for two. I apologize in advance, the design is a little rough I just havn't had the time to make the model shine but you will get the idea. The boats specs area as follows:

    LOA 29 feet 6 in.
    LWL 25.16 ft.
    Beam 8 ft. 10 in.
    Displacement 10,531 lbs
    DL ratio 295
    Hull Speed 6.72 knots
    SA/D 14.15
    Capsize Ratio 1.61
    LWL to Beam 2.85
    Motion Comfort 33.5

    Thanks Everybody, let me know what you think
     

    Attached Files:

    Last edited: Nov 2, 2010
  2. lewisboats
    Joined: Oct 2002
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    Location: Iowa

    lewisboats Obsessed Member

    Do I detect some Buehler influence there? Kinda reminds me of Juno or Olga. I did the same thing when I drew up my "Pacific Island cruising boat design...right after reading his book. A bit longer at 40 ft but the same chine and deeper Vee configuration. Looks pretty good...However...I think I would go with a Ketch rather than a cutter configuration. Balance them right and Ketches will sail themselves for hours on a tack with little to no attention paid to them. Heaving to is easier and you can drop the main and sail on head sail and mizzen alone in a blow...worth considering. In your current design...I think your CE is way too far forward. On a hull that balanced I would put the lead at around 3-5 percent of LWL. You are looking at serious lee helm with your current configuration.
     
  3. LTDboatdesign
    Joined: Oct 2010
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    Location: Bainbridge Island WA

    LTDboatdesign Junior Member

    Yes, Buehler is a serious influence. I like his designs but for the most part they are too narrow. I have been considering a ketch rig, but don't have much experience sailing them. Thanks for the tip on the CE, Its at about 14% now, i'll see what i can do to bring it back.
     
  4. kenJ
    Joined: Jul 2005
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    Location: Williamsburg, VA

    kenJ Senior Member

    Is it going to have aux power or only sails? If yes, and the radiused cut out behind the keel is to make room for the prop you will have poor handling under power because the prop is below the rudder negating prop wash effects. I find I spend about 80% of my time in the cockpit, as drawn yours looks pretty cramped, as you flesh the design out you may want to consider ways to make the cockpit bigger.

    PS. Great start! too many folks dream and talk, too few actually try to put it on paper.
     
  5. LTDboatdesign
    Joined: Oct 2010
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    Location: Bainbridge Island WA

    LTDboatdesign Junior Member

    Thanks for the advise

    As of now I am planning for no inboard, maybe no motor, maybe an outboard. The cutout is just to decrease wetted surface, move the LCR forward a little bit and maybe help with handling in tight places. I agree the cockpit looks pretty uncomfortable. I'll work on it.

    Thanks, Cody
     
  6. kenJ
    Joined: Jul 2005
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    Location: Williamsburg, VA

    kenJ Senior Member

    I know there are folks that have sailed around the world in motorless boats (recently). But sometimes it just makes sense to have an engine from a safety standpoint. It's been a long time since I boated on Puget Sound, there are several places on the sound where the tidal current can be quite strong...4-7 kts. Most motors won't allow you to buck that kind of current, but should be strong enough to keep you off a lee shore should the wind die. As you redesign the cockpit, you might want to condider a well for an outboard to maintain the clean lines.
     
  7. frank smith
    Joined: Oct 2009
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    Location: usa

    frank smith Senior Member

    I like it , very nicely proportioned . Is it designed to be built in steel ? What program was it drawn in ?


    F
     
  8. dskira

    dskira Previous Member

    Unfortunately more and more harbormaster require the yacht to enter the harbor with the engine.
    As for marina you know the rule :D
     
  9. souljour2000
    Joined: Aug 2009
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    Location: SW Florida

    souljour2000 Senior Member

    nice design..seems like the perfect 30-footer..which I hope my next boat will be that size give or take...seems like a nice size for your average skinny wallet sailor who wants a taste of big boat but still keeping things a bit more affordable and in the realm of possibiilty...looks like the cabin top of the salon should afford at least 6-feet of headroom...thats important...for that small salon area to feel roomy.. going forward is always going to be tight in any boat under 36-38 so that part I can live with...a nice salon in a boat under 32' is gold...nice job..
     

  10. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    I disagree about the CE on that boat, 14% is about right for a cutter. Take out the "Brewer bite" in the deadwood assembly if you want a well handling boat. Either make it a true divided appendage arrangement or just hang the rudder on the full length keel. As is the lower portion of the rudder will just work in disturbed flow.

    More Olga then Juno Steve, but you know how I feel about Buehler's sail designs. The only thing they have going form them is the fact that most are narrow. In fact, this is his "deal", lean, wholesome sail designs. Of course none of them sail very well and he's all but abandoned them in the last decade, suggesting how they really do.

    Increase the SA/D unless 5 knots is all you ever want to do and only in 15 knots or better wind strengths. An SA/D of 18 with the working sails is safe on this type of hull, assuming a reasonable ballast ratio (30% or more). It also appears you calculated the CE on the geometric centers of the sails. This isn't the best choice. Calculate on the fore triangle area, not the actual area of the headsail centers. You're lead calculations and boat balance will work out much closer to reality this way.,

    This is a fairly fat boat and though this offers a good deal of interior volume, unless you want a harbor queen that sits at her berth and does little else, then lean her out so she can kick up her heels when the sheets are eased.

    It would look better if you incorporate a lot more roof crown in the cabin and some sweep in the roof line profile would help hide the boxiness too.

    Look LTD, if you're going to emulate a yacht designer, Buehler, probably is the worst choice of the current crop of living designers. I've been on several of George's designs and everyone, without exception, has commented that they wish they'd put more sail on it, then what he drew up.
     
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