Am I crazy- Fire Suit ON!

Discussion in 'Boat Design' started by Steve in SoCal, May 12, 2007.

  1. Steve in SoCal
    Joined: May 2007
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    Steve in SoCal Junior Member

    Hello from a new member,

    An introduction and a million questions to follow.

    I have been considering buying or building a boat to live on and do some traveling, I thought about the RV life style but on a boat. I have not seen any boats that fit my style, layout or, design goals in the flesh. I either find something I can adapt or build to suit. The build to suit is the area I am tending towards. This brings me to the first of many questions about building form scratch.

    The style of boat could be describes as a modern lobster boat or classic hard top, the big difference is the scale of the boat. I have come to the conclusion that it would have to be 68-75 feet overall to provide the space I want. I also have a height constraint of 17’ for bridge clearance and draft constraint of 5’ give or take a few inches. I also want to incorporate as much technology in the design and engineering to maximize efficiency. I would like a planning hull that could deliver good economy at both displacement speeds on canals and moderate speed in open water. My starting point is all aluminum construction and attention to weight, using honeycomb panels as bulkheads and flooring where possible. The boat should be capable of off shore passage as well, part of my desire is to cruise the Pacific coast from Mexico to Alaska.

    Now for the real kicker; I would like to build or more precisely subcontract out the work of the boat. Having a yard build a boat this size from start to finish would be cost prohibitive and I have resources for many systems that I would like to use. How practical is this and what builders are amenable to this method of construction. I want a quality built hull and superstructure with true yacht like finish. The systems installed at the time of construction would include the items normally installed excluding engines, generators, HVAC and electronics. I estimate that it would take three to four years to complete the project and so much change in these areas that I want the flexibility to up date as new technology appears.

    How realistic is this idea and what have I not considered.

    Steve
     
  2. SeaSpark
    Joined: Mar 2006
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    SeaSpark -

    maximize efficiency

    A 68-75 feet planing hull is hard to combine with efficiency.

    If you want a drive system based on new technology it would have to be electric . Power generated by a variety of sources.
     
  3. Steve in SoCal
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    Steve in SoCal Junior Member

    The concept is to use what ever technology is best, in hull shape, prime mover and drive style. A DE system is what I am using at this point as a prime mover, I am not clear on a surface drive, tunnels or conventional props. My goal is to maximize the good aspects of economy in a package that still delivers good performance when needed or desired. I realize that 20 plus knots is giong to take 100 gallons an hour more or less. Part of the concern is that at very low power settings on the big engines in traditional drives is not good for the engines or the fuel bill.

    I also am not so focused on speed, if it will plane at 16 and cruise at 20 with moderate fuel flows I would be happy. The boat I am using as a bench mark has a disp weight of 124000 pounds, 1550 MTUS and convential drives. It will top out at 32 knots and they high speed cruise at 28, I don't need bragging rights I would be happy in the low twenties at a less than 2.5 GPM fuel burn. I would ideally see under 2 GPM if all the stars lined up on the technology.

    Steve
     
  4. Steve in SoCal
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    Steve in SoCal Junior Member

    As a quick follow up; economy and high speed my sound like a contradiction however they are not,it is your point of view on economy. The Concord traveled at Mach 2.2 burnning a lot less fuel than any other airplane at that speed and weight. Sure it was higher than a sub sonic airplane of the same weight but, if you consider the speed to weight to fuel flow it was better than the early sub sonic turbo jets.

    Weight is a huge factor in how much power it takes to do a job and I am very aware of that aspect, just looking at different engines the weight saving from one vendor to another could net a 2500 pound saving with a few more HP to boot.

    Steve
     
  5. SeaSpark
    Joined: Mar 2006
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    SeaSpark -

    Other options

    Lobster style.

    Apart from the lobster style boats there is a whole range of options.

    You wish to incorporate modern technologies, they could be expressed in the total design of the boat.
     

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  6. Steve in SoCal
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    Steve in SoCal Junior Member

    I have seen a few tri's that look like star wars fighters, not my style in boats. I prefer classic styling and the lobster look is just an example, the classic look that Mulder has is also very much in the style of boats I am trying to discribe. The boat I am talking about as my example is the Mochie Dolphin 74, I really like the hull design with the flaired bow and roof line if you photoshop the flybridge off, I don't care for the lower side windows. That is the "pig" boat at 124000 pounds. I did some very rough calc's and just building in Alastar and using C32's instead of MTU's you could save just about 20000 pounds. With less weight I would also consider smaller engines and the that is my start point.

    Steve
     
  7. ezombie
    Joined: May 2007
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    ezombie Junior Member

    Here is something that might inspire:

    http://www.globalsecurity.org/military/systems/ship/fastship-specs.htm
    http://www.globalsecurity.org/military/systems/ship/fastship-schem.htm

    "FASTSHIP has a deep V-shaped bow combined with a shallow, concave shaped underwater stern. The planing action occurs as the ship gains speed, causing the waveform to dynamically lift the stern, thereby decreasing drag and increasing stability"

    They built a 18,000 ton prototype ship that planes at 42 knots for the military. Seems that hull shape might be worth looking at. It appears designed for large-scale waterjet propulsion, though. Funny, but it reminds me of a HUGE version of a few of the old super efficient Atkin's designs... the hull is designed to 'surf' on the front end of it's own wake.
     
  8. SeaSpark
    Joined: Mar 2006
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    SeaSpark -

    Planeing

    I'd love to see a Fastship planing in a canal.
     
  9. RatliffFranklin

    RatliffFranklin Previous Member

    Updating Old Designs

    How about a WWII style PT boat updated with new hull materials and gas turbines replacing the Allisons?
     
  10. Steve in SoCal
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    Steve in SoCal Junior Member

    Ah, I feel a nice warmth.

    I like the PT boat idea but I would like a couple of dash 7 Merlin's instead of the Turbine's. Although you could run the turbine's on Bio-Diesel!!

    I typed a big long dissertation on the idea that got lost in cyberspace but a short recap is below.

    Using the Crouch method to solve power/ speed on the model Mochie 74 I had to use a constant of 180 for the numbers to agree with the published specs.

    After that I used my weight reduction numbers and re-powerd with Diesel Electric at about half the installed Diesel Horse Power and came up with a top speed of 25 knots and change and a cruise speed of 20 knots at less than 1.8 GPM.

    I have to verify the fuel flow on the gen sets but the numbers are very close.

    I am no boat designer or Naval Architect but the numbers add up using what you guys say is the holly grail.

    Steve
     
  11. Pericles
    Joined: Sep 2006
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    Pericles Senior Member

    Vicem might offer what you want as regards the hull. Cold moulded with WEST system will deliver a lighter craft than aluminium.

    http://www.vicemyacht.com/distributors.php

    For propulsion, see http://www.ossapowerlite.com/

    Concorde flew much higher than other jet liners, so less friction. Taking the analogy further, a boat that does not touch the waves will not be subject to skin friction, hence better economy.:D


    Pericles
     
    Last edited: May 14, 2007
  12. StianM
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    StianM Senior Member

    Why not make a simple drawin out off it with a few mashurements so people could get a good idea about what your after.

    I would recomend aluminium since that would be cheaper if your building a one off.
     
  13. StianM
    Joined: May 2006
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    StianM Senior Member

    I have ben looking around the internet a litle and diged trough my head for a few hours.

    I think the best way to proppel a boat with the neads you have or think you have would be two diesels and two reduction gears with shaft PTO/PTI and cp proppelers.

    on the PTO/PTI have shaft generators.
    Have to Aux engines.

    At high speed use the diesel engines and the aux engines.

    For lower speed's cut out the aux engines and runn the shaft generators.

    For slow speed cut the diesels engines and clutch them out. Instead runn the aux engines and use the shaft generators for proppulsion power (diesel electric).

    There is some gears that also allow two engines in and one proppeler shaft out, but they are often only made for the big stuff.

    Then you can have a straight 6 and a v16 couplet into the same gear. For harbour operation you can manover with the straight 6 engine, for cruising speed you can runn the v16 and for max speed you runn both.

    The first option I mention is what I belive would be the moust practical and easy one. You could have a engine rom and one generator rom. The shaft generators could be closed design so you could run them as propulsion engines suplied with power from the Aux engines even if the enginerom was filled with water. You would have a relative cheap, safe and flexible propulsion system.;)
     
  14. Steve in SoCal
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    Steve in SoCal Junior Member

    The Vicem boats are beauties and I have thought about them, I am still looking at alternatives to the two big diesels on my project. I have a few major inland canal, river and , lake areas that I would like to explore. These areas combine thousands of miles of low speed areas and putting a couple of big engines at or near idle for days on end is a concern from every aspect; fuel economy, emissions and engine health.

    These areas comprise roughly ten thousand miles of waterways and this may well be the first few years of my cursing schedule so I am concerned about the low speed qualities of the boat. On the other side of the continent along the Pacific Coast the water can be harsh and the distances are great between good harbors. Speed is an asset and a strategy here for a small powerboat. This is also where the economy of speed is important, most planning boats in this class have a very short range at speed and to safely navigate the Eastern Pacific Coast I feel the minimum range should be double what is normal in the industry.

    Looking at the boat in a whole different light with good economy and long range tanks this boat would be capable of crossing the Atlantic via Bermuda and the Azores. I have no idea where I may end up cursing and I originally was going to get a sailboat and do the Caribbean- Med shuffle but the big stick and deep keel prevented me from doing the inland routes. I am not bent on going around the world but I don't discount some long passages.

    I am asking for a lot in a smallish motor boat and I know very few people want anything like this, frankly I am probably a market of one! The express trawler wrapped in a classic hard top shell that can sprint at 25 knots and sip fuel on long passages. A boat that is as comfortable doing the Atlantic as it is doing the Hudson River. Perhaps I am asking for something that is neither practical or prudent to build. I don't have the insight that many of you have on design, capabilities and technical aspects or the training in any of these areas. I am just a guy who is pretty good at figuring out to add two plus two.

    Stian,

    I just saw your last post and I have not thought about that approach. The issues I have with this type of set up is weight, size and complexity. Using Ossa as an example I would have 6 primary gen sets all the same size and two electric motors directly coupled to the shafts. Between the engines, gear boxes, and other equipment the weight adds up quickly.

    The Ossa generators and motors together weight far less than a MTU or Cat V-12's. While the do produce less power they weight as much as 4300 pounds less and take up just a bit more space than the main engines and generators in an engine room. One nice thing about the gen sets is they can be set in a grouping that better utilizes the space. While the installed power is rated at roughly half the diesel horse power the torque of the electric motors is much higher than the diesels and that is where part of the apples to apples comparison fails. My off the wall guess is that the 1600 electric horse power available is close to 2300 effective diesel horse power. That is plenty of power to propel a 100000 pound boat at reasonable speed.

    Steve
     

  15. Steve in SoCal
    Joined: May 2007
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    Steve in SoCal Junior Member

    Just read my post and while I may be cursing while cruising I meant to use the latter in my post above
     
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