Affordable seaworthy cruiser

Discussion in 'Boat Design' started by goodwilltoall, Jul 31, 2010.

  1. hoytedow
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    hoytedow Wood Butcher

    Don't under-rate what Lake Erie or any other Great Lake can throw.
     
  2. hoytedow
    Joined: Sep 2009
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    Location: North of Cuba

    hoytedow Wood Butcher

    No matter how seaworthy the vessel may be, that very seaworthiness is only as good as the knowledge and experience of the skipper. Without wisdom, true wisdom, the whole venture is a dangerous fool's errand.
     
  3. SamSam
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    SamSam Senior Member

    Goodwilltoall, How about some construction details? What are you planning to use this boat for? Pleasure or a mission?
     
  4. goodwilltoall
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    goodwilltoall Senior Member

    Post 71, never claimed to be smarter than Bolger. The most similar boat to jubilee would be the 96' Bolger designed "sir joseph banks". It is almost completely similiar in design other than 70% hull height rather than 60%.
    Changes made other than size include:
    1. Two sails instead of one for lower CE, sails easier to handle and more cost effective, and rear sail can be used as air rudder (easier to balance).
    2. Gaff rig is unappealing because its basically more expensive and hard to find used.
    3. Engine set up different.
    4. Commercial use and not traveling machine.

    Post 72, good post, Lake Erie is unique with the waves it creates, perhaps certain days jubilee might match the wavelengths, but that can happen to any boat 50' long. The bow is narrow, but also notice that 12 feet is devoted to locker space of just fenders and sails, after that another 6.5' for raised platform for double bed, bow is plumb, the mast is set way aft, the rocker takes the bow out of the water for about 3'.
    Thought into bouyancy forward was a major concern, it should be able to ride over waves. Eventhough the hull height is shallow compared to 95% of all boats, at the ends the hull is out of the water and its four feet above water at deck level. Probably the reason you think it lacks bouyancy in the ends is that the narrow beam exagerates the plan view. As mentioned before the dutch barges with thier bluff bows are not acceptable for ocean work whereas the Thames barges were found to make excellant ocean boats by Bolger and the major reason seems to be reduction in extreme forward bouyancy.

    Would have to guess that ark in cross section was rounded at chines, had flared sides (but almost plumb), and the bottom had just slight arc. This is just a guess but if you take any shape and use those lines to design a boat with the ark ratios being used for overall beam, hull depth, and length, the boat becomes superior compared to most fat beam, short, high freeboard boats.

    Also, in regards to jubilee steering like a pig. Longer hulls have better directional tracking than shorter hulls, they are known to steer better. That is one reason for the seakindly manner of long boats. Take any boat, keep hull height and beam the same but lenghten the hull, motion in a seaway always improves other than as you mentioned confronting matching wavelengths. There is less chance of people being thrown around because of violent motion. Yes the hull will roll more that is one reason for using the flat bottom to offset that tendency.

    George Buehler has a page in his book about a typical fat fishing boat (kind of like the ones in "dangerous catch"), in heavy seas they are looking back and see a speck while bashing into the ocean. Then all of the sudden what was a speck turns out to be a hailbut schooner, long and thin, yes rolling but making excellent progress and soon enough it a speck looking in the other direction.

    Post 80, that is true, that is the reason for being a proponent of a safe boat which will also give confidence to crew.

    Post 81, Two methods of construction were described with boat having a hull thickness of 1.5". The first method would have 2x4 stringers making overall hull thickness 3.0"

    Plans as said before would be for traveling the great lakes, Bahamas, and any other place on earth it would be desirable to visit. No pleasure, on a mission to complete my earthly journey, therefore the proper boat is needed when on the high seas.
     
  5. Pierre R
    Joined: May 2007
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    Pierre R Senior Member

    Goodwilltoall if you actually believe what you just typed in post 82 have at it. Seems you mind is completely made up and there is little we can add. Its your life and your money. Good luck.

    My next boat will be nearly those proportions but will not be anything like your boat.
     
  6. EuroCanal
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    EuroCanal Junior Member

    Ark cross section

    Here's a page with a cross-sectional drawing of the Ark:

    http://www.6000years.org/frame.php?page=noahs_ark

    It's pretty much as described above - kind-of oil-tanker-shaped.

    The site also has the coordinates to a site of an Ark-shaped feature on top of an ancient mud-slide. (Ark remains or geological formation).

    In my opinion, a Dutch sailing klipper is better than a Thames barge in open water, but neither is really suitable for ocean work. Even for the short trip from the Amstel (Netherlands) to the Thames, you would not risk it in anything except perfect conditions.

    All barges have the same problems of being overly-stable, so 'snapping' quickly back to horizontal from a roll - very tiring for the crew and the hull. They have little freeboard and can easily take on water. The shallow flat-bottomed hulls and can't 'grip' the water like a keeled boat will. Around estuaries, with the lee-boards up they're even more of a pain to steer - they skate sideways around curves and follow the currents.
     
  7. apex1

    apex1 Guest

    This guy is coming from nowhere and going back there, thats all.

    The approach was wrong to start with, and then every detail was worse than that.

    The stubborn " I know it can be done, and you have to make it come true" we have seen here so often, it is really not worth to waste our time with such dream.

    Regards
    Richard
     
  8. FAST FRED
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    FAST FRED Senior Member

    Gaff rig is unpealing because its basically more expensive and hard to find used.

    Used and sized to fit YOUR boat ,a Marcony rig is harder to find than winning lottery numbers.

    A gaff rig has the advantage that most any size light pole works as a mast or boom or gaff spar.

    Aluminum scrap, maybe 50c a pound from a local municipality.

    A further advantage is the sail material is lightly loaded and does not require any great skill to construct.
    Just a used commercial $100 zig zag sewing machine, and some time.

    Going the "wrong way" round the world , Marcony rig is really useful,

    like most cruisers reach or run? gaff is just fine and way cheaper.

    FF
     
  9. goodwilltoall
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    goodwilltoall Senior Member

    Greetings to all,

    Post 83, Would like to see your design if as you say has similar proportions.

    Post 84, Reason for mentioning the thames barge is Bolger used it to design as he said his most seaworthy ocean going sailboats. As you said barges have tendency to snap roll, hoping jubilee design because of length has a more mild form of rolling.

    The shape does give shallow draft, it is what it is. It would have been possible to give it deadrise which would then have added say 12", then attach laminated 2x6 to give it a full keel for leeway, which then would have made jubilee 3'-1" to 3'-4" in draft with the same displacement. Maybe that would have appeased many of you but would not be acceptable for intended purposes.

    The shallow bottom will slip and not grip like a full keel, that is one reason for keeping 90 degrees chines to aid in leeway resistance. Around estuaries jubilee will be able to enter them, whereas any other type is not even able to enter, so the arguement with boards up is moot.

    Post 85, Apex, since the beginning of the thread you've made posts saying jubilee design is irrational, and when questioned for reasons why, you refuse to give answers because of claim "your time is limited", now you chime in again but without any value to your comments, only to discourage which I wont let you. Dream for some, nightmare for others.

    Post 86, Fast Fred, from previous posts of yours, there's alot of respect for your ideas, this will show my lack of understanding in regards to sails. I can not see how a Bermuda/Triangle/Marconi rig is harder to find. The gaff rig does seem as the ideal rig but that is the one that would be winning the lottery if a whole set was found.

    Would like to attach marconi sails to mast with lines without tracks just like the gaff so light poles should also work. Do have an apprehesion for having to make design and make sails. Its seems the materials for cloth are expensive as well as sailmaking equipment, furthermore investing time learning and making sails would take away from actually sailing.

    One other thought, boats of this hull design have been built, the as39 "loose moose" had similar hull shape and same draft and crossed an ocean along with traveling tens of thousands of miles quite successfully. Another sailboat, the Mac26 (the sneering begins) also had 12" draft with 7'-9" beam.
    Now that boat is not considered ocean going, but if you double the hull length, lowered freeboard a little, added second mast, the boat then would become a tremendous seagoing boat.

    These are things that have been done before, it is possible.

    How much ballast would be enough to self right?

    Gotta go, peace.
     
  10. frank smith
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    frank smith Senior Member

    Bolger's "Romp" is not really a barge, it does have a mid section that is "barge"like , but you have to take the the whole boat int to consideration .

    The AS39 might give some indication of ballast, but it would be only a guess.
    See if you can find an article by Bolger on self righting in shallow draft boat.

    Some how this all sound familiar ?
     
  11. goodwilltoall
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    goodwilltoall Senior Member

    Greetings,

    Have heard no thoughts on the 600sf sailplan.

    From looking at other similar designs, overall height of masts should be limited to 37' - 40' above water line, this is just in general and of course there are many other factors, but there has to be a starting point.

    Secondly, most other shallow draft boats have low ballast ratios of about 15%
    to 30%. This is odd, you would think that shallow draft would require more ballast than deep draft boats. Since there needs to be reliable self righting and not much information is available of shoal draft stability it is hard to make conclusions.

    So is 35% inside ballast ratio with above sailplan doable?

    Without knowing the science of exact engineering for allowable stesses on certain materials (sail cloth, masts, hulls, ballast, heeling, and hundreds more formulas and calculations); observation of other successful and similar designs and why they work well becomes the means of learning how to apply those principles into a design that you also would want to work well in the same conditions.

    As example: using the as39 again for overall shape, draft, sail area, mast height, and ballast; we can conclude that using similar design characteristics certain behaviors will result if we stay near those parameters.

    All new technologies, techniques, or designs in the end are deemed acceptable by being able to observe them performing as intended. Calculations and formulas help, but they are not always necessary. So if some of you through engineering can say above ratios will or will not work, and if some people through experience and first hand knowledge can also make a determination, those thoughts and ideas will be appreciated to answer questions I have.

    Peace.
     
  12. frank smith
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    frank smith Senior Member

    This has been discussed here before and there are some good treads that can be found through the using the search function of the forum.

    Frank
     
  13. goodwilltoall
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    goodwilltoall Senior Member

    Eurocanal,

    Went to site located on post 84, now that would be a worthwhile trip to take on jubilee. Cross the Atlantic into the Mediternean, then stop in Istanbul to visit the beautiful people and country of Turkey, from there take a bus or train to ark location and observe the most seaworthy ship of all time.

    Fast Fred,

    What do you think of these two ideas:

    First, if you notice in the stern there is 5.5' dedicated to engine area. It is covered to prevent swamping. Engine would be required in rivers and places like intercoastal waterway. Are you familiar with the long tail engines or BOB type engine (Bay of Bengal)?

    Both are direct driven with propeller connected to shaft which is connected to engine (would thrust bearing be needed?) The BOB engine is pivoted at engine mounts and so prop is able to lift out of the water. Do you think one of the 15-20hp diesel reefer units you describe could me made to work in that fashion?

    Second option is to take the horizontal shaft diesel engine and turn it 90 degrees so its awthartship. Engine would be mounted to beefed up hull bottom in that area, then a chain or belt is connected to a 3'-0" diameter x 24" paddle wheel that can also be lifted up out of water.

    If this would work it might be cheaper than outboard and diesel is more reliable and safer. People will say why not have goat for milk and chicken for eggs as well, dont want to be a laughing stock, the first mechanically propelled boats had paddlewheels until propeller screws where found to be more efficient. Another thought to consider in the quest for affordable, seaworthy cruiser.
     
  14. goodwilltoall
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    goodwilltoall Senior Member

    Frank Smith,

    Post 90, Its been discussed before but not for jubilee design in particular.
     

  15. Pierre R
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    Pierre R Senior Member

    This is not really adequate to drive the boat if the boat is heavy enough for its waterplane. That said the beam and ballast ratio may not match either.
    The ballast ratio is not determined by a number but by what is necessary for stability. Stability is determined by the lines and weight distribution.

    This is not a sure fire way of designing a boat to say the least.

    I am afraid that the biblical ark is not in that category.
    You really have not asked question with enough information to determine an answer. When general answers are given you write them off as not meeting your criterion. You are difficult to help as you are not really designing a boat in time tested sensible ways that have worked for at least the last 200 years.

    Cheers.
     
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