Theoretical recreational boat design

Discussion in 'Boat Design' started by endl3ss, Apr 11, 2008.

  1. endl3ss
    Joined: Mar 2008
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    Location: Norway

    endl3ss New Member

    Hi everyone!

    New member here, and this is my first post.
    I'm learning a lot on this forum, and I'm reading it every day nowadays.
    At this time, I'm not a boatowner, although at some point in the future, hopefully within 2-3 years, I hope to change that.
    Haven't really decided on what boat yet, but it will almost certainly be a cabincruiser/daycruiser type of boat. But right now, it's too far off to make a decision. Also, I have to apologize for the long-winded first post, and also sorry if this subject has been discussed earlier, but I haven't been able to find it.

    Anyways, the reason for this post is of a more hypothetical nature. I see a lot of knowledgeable people here, and most of you seem to be professionals. I've got a theoretical project, possibly a complex one, that some of you might have a solution to. Now, this is not a competition, it's not a "request for proposal", it's not a pissing-contest (although, for all I know, it might become one...), it's just a question about your opinions. Ie, what do you feel would be the "correct" way to go about this. For all I know, there might not be any "correct" answer to this, it might be dependant on tastes, experiences and other things.

    Right, here goes:
    As a thought-experiment, I'm looking for a boat with the following requirements covered:

    - Speed: Max cruise 50+ knots at as rough a sea-state as possible, preferrably including sea state 2. Max speed as fast as possible.
    - Range: at least 500 nm at max cruise.
    - Fuel-type: Marine Diesel.
    - Full load displacement: Absolute Max 50 metric tons (apprx. 110,000 lbs).
    - Classification: A, ocean or B, offshore.
    - Fresh water capacity: ca 1000 litres.
    - Living area/space:
    - 4 double-bed cabins/staterooms
    - 2 bathrooms with shower and toilet
    - 1 Medium large galley
    - 1 saloon capable of comfortably seating 10 pax
    - 1 Outdoor saloon for 10 pax
    - 1 Indoor helm-position, seating for 2 "crew"
    - 1 flybridge helm-position, seating for 2 "crew", as well as sitting-group for 5-6 guests and a table. Possibly also a sunbed or three.
    - 1 forward area with outdoor yakuzi and 5-6 sunbeds
    - 1 swimming platform

    Those are the base requirements, if possible to attain. Now I've not listed EVERYTHING that needs to be on the boat, like electrical system and navigational aids; I've only listed what definitely NEEDS to be on the boat that could affect its size and hulltype. The boat must of course have whatever electrical system and nav aids that is needed for a boat with these spesifications. The boat should conform to relevant directives, like the RCD and whatnot.

    Apart from that, the boat should be as ecconomic as possible - all the while acknowledging that it probably won't be anywhere near ecconomic. It should also be as maneuverable as possible, both in-harbour, but also at sea. Main area of use will be inshore, and it should be able to navigate shallow and tight waters at max cruise speed. For an example of what I mean about tight, see pics below.



    However, even given its mainly inshore use, it should conform to at least category B, offshore or possibly even A, as it should be able to transit longer stretches of water offshore. I'm not too familiar with boat design categories, so it is possible that category "B" is sufficient. It should have a smooth ride (dependant on sea state of course), and should be as rough sea worthy as possible. Finally, it should be able to get into a decent-sized marina.

    As for the living-arangements, these should in general be relatively roomy and comfortable, but NOT luxurious. Some might argue that a Yakuzi is pretty luxurious, but apart from that I'm not looking for a "luxury apartment at sea". The moment you no longer feel that you're at sea, but instead sitting in your London/New York/whatever luxury penthouse, then it has gone too far. Comfortable, roomy and functional but low-key is what I'm after. Pershing 90' luxury detailing is not the idea. Crew would be the owners of the boat, so no separate crew-accomodation is necessary.

    Here's the kicker:
    This is your sandbox. Within reason, you can use any means to make this happen. Hull-type, propulsion system, engines, building materials etc is all up to you. When I say within reason, I mean that I don't expect to see any liquid hydrogen-fuelled, rocket powered, all-titanium hulled boats. But apart from such extremes, almost anything goes. Gas-turbine engines, waterjets, surface-drives, Catamarans, SES's, Hyrdofoils, Jetfoils, M-hulls, Monohulls, Trimarans, wave-piercing, name it. This is also why I've not specified dimensions, as this probably will be dependant on hull-type. The max displacement however, is an absolute - 50 tons max. I should say that attaining the requirements by using a more exotic hull-type is much more acceptable than going for insane engines, all in the name of ecconomy. Another thing that needs mentioning, is that the idea is for this boat to be FAST - fulfilling all requirements but ending up with a 20 knot boat is a non-starter. Also, the intention is not for this boat to necessarily be a homebuilt type, I'm guessing this would have to be built by a shipyard of some sort.
    Now, this is probably appearant from the above...I'm not a naval/marine architect/engineer - not by a long shot, never will be either. ;)
    I might have come up with some requirements above that just isn't possible to combine. If so, please say so.

    At the end of the day, what I'm after is this:
    If YOU were tasked with designing a boat complying with the above requirements, how would YOU do it?
    What hull-type would you choose and why?
    What propulsion and engine would you choose and why?
    What layout would you choose and why?
    I would love to see a discussion on this...pros and cons on different solutions.

    Thanks in advance for any inputs :)
  2. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    My best suggestion is to contact a designer and have some preliminary sketches drawn up. You're requirements are unique, but not insurmountable.

    There is no correct or preferred shapes or hull types that would suit the homogenous set of compromises, that would encompass a craft like this. In short, a custom design is what it will take, though there are a few possible offerings, from several production and limited production manufactures, that would hit the majority of your desires right out of the box. Needless to say, this would be an expensive vessel and likely quite large, which means your pocket needs be equally as deep.

    If I was "tasked" with a brief such as you've listed, I'd start you off with a questionnaire for all the things you haven't listed, after ascertaining your budget restraints. The design process is a drawn out one, with the designer often finding it necessary to "pull teeth" to get honest answers to desires, absolute needs, distinctions between gingerbread and necessity, etc., then incorporating them into a decision process that eventually guides the boat shape, systems, equipment, etc.

    Opinions will vary like the wind blows, none being anything close to what you desire. Yacht ownership of this caliber is quite personal and no one other then you in concert with a designer can determine how personal it will be.
  3. balsaboatmodels
    Joined: Jan 2007
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    Location: Boonville, MO, pop.8700; & 415 buildings on Nation

    balsaboatmodels Junior Member

    Is that wise?
  4. rambat
    Joined: May 2002
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    Location: LA

    rambat Member at large

    Yacht not boat

    What you describe is well within the ability of a somewhat familiar hull form in your area, the SES. Allot of development has been focused on this hull form in the past few decades and it seems they have not come up with a more viable concept to improve range, speed and comfort. I have a SES yacht design that is geometrically the right size, but a little over powered for 50 knots. Your design could have less engine weight and bring this design down to your 50 ton figure. you can see this 15 year old design at:
    It was based on the proven Bell/Textron 110' SES's built for 40 knots service in the Gulf of Mexico during the 80's. Most yacht owners have not found a need for speed or were turned away from SES by their captains whom saw the skirts as an unwanted hassle to maintain. IMHO this hull form will be reconsidered when green sensitivities and fuel cost touch upon those few with a strong desire for speed and the wherewithal to commission large, fast motoryachts.
  5. endl3ss
    Joined: Mar 2008
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    Location: Norway

    endl3ss New Member

    PAR, I hear ya.
    This boat would probably be a one-off, and would require custom design....probably. Although as You say, there might be production models that might meet the requirements, or most of them anyway. Your thoughts on hulltype would be appreciated though.
    As for size, «likely quite large»; I guess large is subjective, and the same can be said for my requirements of «roomy and comfortable». To elaborate a little on that; for this vessel I would be happy with something designed along these lines:



    and not necessarily something overblown like this:



    From a general public safety viewpoint in recreational lanes, I would obviously say no.
    But the requirement to be able to navigate such waters at that speed is more of a technical aspect with regards to hull maneuverability and seakeeping features, as well as propulsion system and nav aids. It should be CAPABLE of such maneuvering.
    Whether it should actually be driven like that at any given time and in a given area, that's another issue. Of course, I fully acknowledge that if the boat is capable of this, then we will always have one inconsiderate **** that will act like an a**hole, and drive around like he stole the boat, wherever he is. I've seen people like that, even in areas tighter than those evident in the two pics. The pics in my first post might be a bit bad in that regard, as they show typical inshore recreational lane areas with lots of huts, houses and recreational crafts on the water, while even further from the mainland you will find similar tight waters here in Norway, with very little or no recreational traffic. And for some of those areas, being able to transit and maneuver at that speed, is pretty safe from a public viewpoint, as there are no other vessels around. As long as the boat is technically capable of it, that is.
    I have been on a few trips in military RIB's and assault boats in such areas, racing about at pretty high speeds, even at night, can't even remember ever seeing civilian vessels out there.
    Heh...come to think of it, I've even been aboard one of the Navy's old frigates, KNM Bergen on it's last trip before decomission, doing tactical inshore navigation runs at close to 25 knots within similar tight (not shallow!) waters. Pretty hairy driving, with shoals, reefs and small islands sliding by as close as 30 ft :D Awesome driving really...shoulda brought a videocam...

    A few example pics, from the Navy:




    Do note that I'm not saying that «our» boat should navigate as «offensively» as those CB90's in the above pics; the Navy does of course have their specific mission needs that require rides like those pictures show. And I can see that «our» boat would be larger than the CB90, meaning it would probably be less maneuverable... Also, the fact that these are military pics does not mean that this boat is meant to be a military vessel, the pics are just given as example of the type of waters I'm referring to, and the speed at wich some boats are able to safely navigate through them. This is not pics from the usual inshore recreational craft lanes, but further out along the coastline.
    And yes...I would LOVE to have one of those CB90's, even if it is butt-ugly.... ;)

    To rambat:
    That's a wicked-looking yacht! Very nice!
    It looks quite a bit larger than I had envisioned, but then again, I don't know how large my requirements would make the boat...or yacht, but see comments and interior pics further up the post. I have to admit that I'm kinda taken by the SES concept in general, although I know to little about it to make any assumption about the practicality for a smaller vessel. Are there any downward size-limits to such a hull design, in terms of SES's no longer being as effective as other hull-types? And how is the relationship between the extra power needed for lift-fans with regards to using the same extra power for direct propulsion? I'm guessing that the SES might come out on top anyway, since you have brougth up this design, but would you for a given speed use less power for lift-fans and propulsion combined than you would for a similar sized planing/semi-planing/or other hull using all its power for pure propulsion for the same speed?
    Oh btw, is that a piano drawn on the main deck of your design?

    Thanks for inputs so far!
  6. Jarrod
    Joined: Jul 2004
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    Location: New Zealand

    Jarrod Marine Designer


    We're more than happy to help you out.

    Currently we're working on a large high performance asymmetric catamaran hull form, powered with Hamilton Jets which has similar performance objectives, but is unfortunately commercially sensitive so we're unable to release any details at this stage.

    But if you contact us we can provide you with a preliminary design, utilising similar characteristics of the one under development, you will need to sign a NDA though.

    I look forward to hearing from you.
  7. endl3ss
    Joined: Mar 2008
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    Location: Norway

    endl3ss New Member

    Whoa man.....whooooooaaaa! :)
    I've checked out your site, and some very nice designs there.
    But as mentioned, this is a purely theoretical thing. The boat/yacht/vessel I'm outlining above is NOT the boat I'll end up with. I would just like to see opinions on the general way to go, for such a craft.
    I've seen a lot of talented people chiming in on this forum, arguing (not bickering) the pros and cons of different GENERAL designs, and that is what I'm really after, although specifically directed towards a recreational craft.
    I guess I might have made my original post even more vague, and asked "In what direction do you all think recreational craft design will go in the near future?" I just figured that a few more or less specific requirements might narrow it down a bit, and be easier to answer.
    Anywhooo....THAT is what I'm really after here.
  8. rambat
    Joined: May 2002
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    Location: LA

    rambat Member at large

    Recreational boat future

    The SES is always bigger for a given set of beds than a monohull or conventional catamaran because the below deck is taken away for the air-cushion volume between the slender sidehulls. A future fast coastal cruiser like you describe is nice, but a 50 knot speed requires an expensive high tech power package. It does not help if its only "capable" of 50 or not, it must still be built structurally and powerful enough to do so. The SES really separates in improved performance when you get into the 50 knot range. Most SES's have been done for the 35 to 40 knot range and the advantage has been less apparent. I think if we extrapolate from today's trends in boating. the future of recreational boats is like cars, less technical innovation, mostly styling and amenities. Of course there are new car hybrids and 200 mph speed demons but not in any significant numbers. The bulk of the automotive market is still like the cars of 20 years ago, except with new styling, much higher QC, creature comforts and almost perfect exterior packaging.

    Like cars In twenty years I predict the future will belong to even more Butiful and luxurious yachts. The owners of pleasure yachts now and in the future are not as affected by fuel cost like most of us. The primary use of recreational "cabin cruiser" yachts is short family "casual" trips, dockside retreats or corporate/marketing entertainment. I read with wonder on this forum that many find it superficial and not very purposeful to have a boat with no "working utility", but that is exactly what a hard driven successful buyer of the pleasure yacht wants, a pressure relief pad.

    Taken to the extreme I can envision a future low maintenance, stabile, failsafe yacht with extraordinary excursion toys and spa like layouts. Imagine small research labs on board for intellectual stimulation. The highest end yachts have always shown the way to what is filtering down to the mass market, most mega yachts today are tied into global network of sea health monitoring via internet (see Sea keepers society)

    High speed could come of age when a "corporate jet" type of yacht is offered, such a craft will require 100 knots or better for any meaningful continental mobility. However operations via sea state limitations and open sea safety will have to be on-par with jet aircraft, a tough task.

    The growing retiring consumers will seek more spacious livaboards, I bet the future will show more than a few low powered but extremely "fashionable" barges. They wont appear as a barge and will be highly automated and totally connected to global media and weather stats. The biggest breakthroughs could be in the development of a much more affordable and robust "yacht like finish". The existing and growing trawler market has the livability and could dominate the market if they were as appealing as their "white yacht" harbor mates without the cost required for the exterior finish IMHO.
  9. kach22i
    Joined: Feb 2005
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    Location: Michigan

    kach22i Architect

    The SES will do the shallow and fast, from the look of those rocks around the island, might be a good idea too.

    Is there a shell floating around for this old proposal?

    Is this SES shell still avaliable Rambat?
    SES Photos (many):

  10. rambat
    Joined: May 2002
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    Location: LA

    rambat Member at large

    SES Shell

    Kach, that 40' SES of mine was lost in Katrina, but last year I went to Belgium with a client to survey a "surplus" 105' SES ferry shell, the owner only wanted less than the cost of materials! (180 000 € " as is where is ") It would have been the worlds fastest SES motoryacht if it wasn't on the other side of the globe.

    Attached Files:

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