From operational concept to SOR

Discussion in 'Boat Design' started by cmckesson, Sep 27, 2016.

  1. cmckesson
    Joined: Jun 2008
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    cmckesson Naval Architect

    Gents, I would be interested in seeing how you all would translate the below "operational concept" into a set of naval architect's design requirements. I have posed this as a task to my students, but I think they would appreciate seeing what questions and twists and turns a set of professionals come up with.

    If you are willing, here is the Con Ops:

    "The Motor Yacht

    Chris and I always start our day with coffee. Being minimalists, we're happy either making a fresh pot or reheating on the (at least) three burner stove; no need for a microwave while we're cruising. Generally I'm the first person up. With the stainless percolator brewing (stainless because anything other rusts or corrodes in the marine environment), I open the companionway doors and step out to inspect the morning.
    Our motor yacht floats peacefully at anchor, the sun slanting yellow across the bench seats of the cockpit. I lift one to rummage in the stowage inside, pulling out a jacket stashed there for dawn contemplations. Binoculars wait in their special box, mounted on the bulkhead next to the exterior instrument panel and chart display. After a quick 360, checking for boats that have dragged in the night and are now too close, for wildlife, for anything else moving about, I replace the binocs and duck back below. (We anchored in 65 feet last night, deep for us. Then we had a little wind blow through the anchorage. This is why I was concerned that others might have dragged.)
    The coffee has begun to perk. With plenty of galley cabinets, I pull out two cups, sugar and creamer. I take a cup to our large stateroom, placing it within easy reach of the husband mostly invisible in our queen bed. My own cup in hand, I slide into the 6-person dinette, running a hand over its polished wooden surface. The fiddle rails around the edge will keep anything parked there from crashing to the sole if we roll.
    I keep a journal on board so opening my computer, I plug it into the convenient power strip. 30 minutes of typing and the mug is empty, the pages full of the last few days of cruising, day hopping along Texada Island, into Smuggler Cove (where we stern tied), across the Strait of Georgia and through the narrow, swirling waters in Dodd Narrows. After 6 weeks working up the Inside Passage, into the Broughtons and back, at a modest 6-knot pace we've made excellent time from Desolation Sound back into the Northern Gulf Islands. This day we'd return to our slip in busy Burrard Civic Marina.
    Our galley is one of my favorite places on the boat. Today is bread baking day, so out comes large bins of flour, yeast, olive oil, salt, home canned butter and milk powder. A large mixing bowl and three bread pans and I start the process that brings great satisfaction. Good bread making takes time, so I shuffle between that and taking stock of the stores we have left, preparing to move back into city life.
    I keep a running list of goods on my computer, so I open every space from can storage, snacks and cookies (not much left there lol), eggs and cheese and dry salami, baking goods like flour and sugar and cornstarch, herbs and spices, dry goods such as pasta, instant potatoes, all my dehydrated vegetables and fruits. With no refrigeration and only a small icebox, most of our stores are shelf stable. The liquor locker is almost bare, a third of a bottle of rum and one bottle of merlot look forlorn there. I tap away, updating my files, mixed with kneading and shaping bread dough. With the oven preheated to 350 degrees I pop the pans in, setting my timer for 30 minutes.
    Chris has been up a while, helping himself to a second cup of coffee, settling into his office space to check emails and put the finishing touches on the upcoming semester's class notes. He has a panel of three monitors and a desktop computer, powerful stuff for a yacht but perfect for the professor working as we cruise. The office doubles as a navigation station, with flat storage for our many charts, shelf space for cruising guides, tidal information and ship's log rubbing elbows with professional journals, textbooks and the odd sea story.
    The perfume of baking bread fills the boat from her forepeak, through the large main cabin, and into our stateroom. I start there, enjoying the light dancing through the portholes and checking that everything is stowed in its place ready for sea – in this case crossing the Strait once again, heading for Vancouver. Chris's large hanging locker door is open, I shut that and check the shelf space along the bed for things that could roll or crash. Opening my own locker, I pull out a visor and deck shoes. Who knows whether I'll want socks, so I ignore my drawers for the time being, hoping for a sunny day.
    I stick my head in the guest room but everything is tidy there. The head needs some attention, I stow all the bottles and jars set on the counter overnight, and pause to admire our large Mexican sink, its bright colors mirrored in shower curtain and braided rug.
    With some trepidation I move on to the storage closet. No telling what's gone on in there, as it contains tools and material for boat repair, model making, our big Sailrite sewing machine, all my art and quilting tools and supplies. Miraculously I find it reasonable, stow some rags and a can of paint, and secure a brush lying on the swing-out work bench.
    A quick stop to pull out the bread and turn off the oven, and it's time to up anchor and turn toward home.
    In Sundance, our sailboat of many years, we led our anchor chain aft to the cockpit to grind it in with the sweat of our brows. Our aging bodies dictate that our new boat has an electric windlass similar to fishboats, with a hurky steel cable wound around a drum. Our main anchor stays permanently attached but we keep several others on board; from a (slightly) smaller lunch
    hook to a true fisherman style anchor that looks decorative but holds incredibly well on a rocky bottom. In anything resembling stormy weather we automatically put out two anchors. I stand ready at the outdoor helm while Chris walks forward. Anchor cable rolls in, Chris checks the anchor for weed and makes sure it's properly seated, while I put us in gear and motor slowly
    through the anchorage, with no wake to disturb late sleepers.
    Also very little noise, as we have held onto one aspect of Sundance that we both love, our solar powered motor. We use it in marinas, leaving anchorages and other places where we want quiet, only turning on the big diesel engine when we're away from other boats. The electric motor has a range of about 10 miles, so if we're not in a hurry we might use it alone to hop from one bay to another.
    Watching my depth sounder and checking my chart, I motor through the narrow entrance to our bay and point toward Porlier Pass. Porlier is an easier passage than Dodd Narrows, where you must catch the tide just as it turns, but still there are challenges. Time to fire up the engine, we'll need its power. A quick check does not show the captain anywhere on deck.
    Turning on the intercom, I ask, 'Permission to start engine?'
    'Permission granted!' comes back. I wouldn't want to switch on with Chris doing some last minute adjustments. The diesel throbs into the day. Letting it warm up, I continue under electric for a few minutes before switching over.
    We've missed the best time to run the pass, at high water, but can catch the ebb, putting on power to tackle the whirlpools, overfalls and upwellings of a typical Gulf Island channel.
    Harbor seals, Dahl porpoise and seagulls share the pass with us as we power through, but no orca today. Cliffs and evergreens slide by on either side, and then we poke our nose out to see what's happening in the larger waters of the strait.
    The Strait of Georgia can develop serious wave action if the wind has been blowing a steady 20 knots for more than a few hours. Today looks benign but I switch on the VHF to listen to the weather, tardily because I should have done that while bread baking but forgot. 'Strait of Georgia, south of Nanaimo, wind 10 to 15 knots.' Excellent, no small craft warning. Our cruiser is built to deal with heavy weather, but it's more comfortable not smashing through three foot slop. We motor out, leaving behind the long, brown and green islands and pointing toward the greater mountains behind Vancouver. Chris comes out of the main salon. I hand him the wheel and settle on a bench seat, enjoying blue sky mirrored in blue water.
    Our crossing is peaceful. The miles flow past to the screech of gulls, the shush of water along our hull. One container ship crosses our bow, heading for the big terminal in Vancouver.
    We slow to let it pass, and then plow through its wake, a few three-foot combers that we take on the bow. Open blue water gives way to the rocky cliffs of Point Grey, and then English Bay with its beaches and sun bathers.
    A strong ebb tide is running out of False Creek. We won't be using the electric drive to dock today. Our yacht powers against the current, breasting the flow to turn into the marina.
    Once out of the stream Chris throttles back, and we make our way down the fairway, past docked sail and power boats to our slip.
    One of the reasons we switched from sail to power is my growing arthritis. Leaping from boat to dock causes my knees great pain. I've rigged our dock lines, taken from their locker in one of the cockpit bench seats. From the stern of the motor yacht it's an easy step onto our dock.
    Chris brings us in, I take the stern line and slip it on its cleat, jog up in time to catch the bow line Chris tosses. Home again, after another wonderful summer cruising around the waters of the northern Salish Sea."
     
  2. Richard Woods
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    Richard Woods Woods Designs

  3. gonzo
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    gonzo Senior Member

    I think that the first statement "Being minimalists", is proven false by the description of the motor cruiser with plenty of galley cabinets, special in a special box, a pillow exclusively for dawn, etc. A minimalist would cruise in a skiff or canoe. They even carry a computer and a power strip!
     
  4. messabout
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    messabout Senior Member

    That tale will pass for a pretty good SOR. It is also a pleasing story, well done. One of the things not mentioned is expected cruising speed. The students will need to know what that is.
     
  5. sharpii2
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    sharpii2 Senior Member

    But this term is very likely to be used by a client. It is considered so fashionable these days. Besides, it's a very relative one.

    I'm sure H.D Thoreau's idea of "minimalism" differed form Cornelius Vanderbuilt's.

    What we're looking at here is a minimalist seven to ten ton yacht.
     
  6. gonzo
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    gonzo Senior Member

    If your client uses terms to be fashionable, as the designer, you need to quantify them. Use a decision matrix or a weighted matrix to help the customer define what those terms mean to him and which have more importance than others.
     
  7. Petros
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    Petros Senior Member

    LOL, I like it. the customer is always right, eh?
     
  8. lucas.castro
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    lucas.castro New Member

    sharpii2, could you give me some insights on how you got to the seven to ten ton yacht estimate?
     
  9. gonzo
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    gonzo Senior Member

    That is a fair estimate of a trawler of the size you describe.
     
  10. Ad Hoc
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    Ad Hoc Naval Architect

    Not easy.

    An SOR translates into cost and performance. There is nothing that suggests what is a maximum or minimum speed requirement other than the distance travelled and the time taken which is subjective not an absolute.
    The length and draft and beam could be inferred from the locations travelled and the harbours/berths visited but nothing explicit and thus open to error in interpretation.

    The only real SOR one can obtain is the power requirements and the fact 6 berths are required.

    If this landed on my desk, i'd send it back saying nice story, but what is your budget and what are game changers in the SOR since without these it is far too woolly and far too subjective. It would only elicit a vast array of solutions and very hard to criticise any, since the requirements are far too open.

    An SOR requires clear constraints and targets rather than a narrative of inferences.
     
  11. philSweet
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    philSweet Senior Member

    I would begin with basic GA considerations such as stairs and what needs to be on common elevations given the age/health comments.

    Resupply interval and operating range need to be identified.

    I'm guessing a Wilcox Crittenden and folding sink in a 2'x3' toilet-shower combo isn't going to cut it.

    Basic info on preferred interior and exterior styling is worth knowing early on. A wooden dinette table isn't quite enough info.

    Dingy, dingy handling and dingy stowage requirements need to be listed.

    Considering the e-power requirement, the next question would be do you want to go all-in on a DC bus controlled boat. The e-power requirement is going to put you about $15k closer to one than a non-hybrid.

    General strategy regarding ease of use should be discussed. Electrics, hydraulics, or design for low power/infrequent adjustment etc.

    Maintenance accessibility/owner maintenance concept. This could have an affect on overall length and ownership costs.

    Probably not in play, but road transportablity should be asked and answered.
     
  12. sharpii2
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    sharpii2 Senior Member

    I started by thinking of the space needed for two staterooms, an enclosed head, with actual room to move about in, once the door was shut, a galley with a three burner stove, with oven, pluss space for the professor's three monitors, not to mention the dinette big enough to seat six people.

    I considered that four of those six could be guests from other boats.

    But this vessel kept getting bigger and bigger, as I considered where I'd put all this stuff, so I concluded that it would be a displacement cruiser with a Length of 30 to 40 ft (most certainly closer to 40 ft), and a Beam of around 12 ft.

    It became very clear to me that this would be client likes his comfort, so the boat not only had to have enough space for this comfort, but also wnough displacement for a comfortable motion while at sea.

    I presumed a mono, because speed seemed to be trumped by comfort. If the client clearly wanted speed, I might have considered a multi. But with the mention of bad knees and getting on in years, seemed to veto climbing down into narrow hulls.

    The first vessel type which came to mind is a troller yacht with a larger than typical pilot house (for the galley the big dinette, and the professor's almost exclusive work area, referred to as his 'office'). By this discription, I did not assume it had to be closed off, but I did assume that it had to be workable when the galley was busy, but not so much while the vessel was underway.

    My displacement range is a true guesstimate, but an educated one. I figured the boat should have a heft factor of atleast 1.0, but would probably need one more like 1.5. Anything less than this range would probably be bounced all over the place in any kind of seaway. Displacement (mono) powerboats have to have a comfortable roll period, as well as the ability to power through a chop without ecessive slamming, as they spend much more time underway than their planing cousens.

    I have never designed a boat for a client, but I already know that its not so much what the client says, as it is what he means.

    So the first term I ignored was 'minimalist'.
     
  13. Petros
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    Petros Senior Member

    Ad Hoc I think gets it right,

    Without a budget and a clear vision of what they want, it is not easy to get specific. A client like that sounds like a lot of head ach. It reminds me of a number of deign projects in my own firm where the client had no idea of costs, nor no clear idea of what he wanted, just a lot of disconnected and vague notions. It never went well, redesign after redesign after redesign...typically the client would end up abandoning the project. I try to identify those types early on when I meet new clients and either refuse to take on the project (making some excuse like I am too busy for it), or ask them to think it through and come back later, and suggest they just save themselves a lot of trouble and anguish, and find something that is out there that is close enough to what they want and buy it. Rather than pay a lot of money to design t(and redesign) something that likely will never get built.

    Indecisive clients are the worst kind, they keep changing and second guessing every little detail, revisiting decisions we had made over and over again over many months.

    Even if they keep paying my invoice for making change after change, it is not very pleasant to take money for your best design efforts, only to have them pay you to do it over again, and again. It is a very costly and inefficient way to get to building plans. I had one client that kept making changes after construction was started, and all during the construction (using another engineer because he was too ashamed to bring it back to me for more changes...I had politely chewed him out about making his mind up the first time before he had me create plans). when I can spot someone like that early on I will try and get them to just find something to buy, new or used, rather than pay for plans and have it built.
     
  14. sharpii2
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    sharpii2 Senior Member

    The most famous client to do that was the king of Sweden. The project boat was the man-o-war VASA.

    IIRC, he wanted to add another gun deck, after construction had already started.
     

  15. Ad Hoc
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    Ad Hoc Naval Architect

    Exactly.
     
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