S O R ???

Discussion in 'Boat Design' started by graywolf, Dec 25, 2014.

  1. graywolf
    Joined: Dec 2014
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    graywolf Junior Member

    Okay guys, you are always saying you need to start with a Statement of Requirements. Here are mine. I have 2 questions: 1-Are they adequate or do I need to add more information? 2-Suggestions for boats that meet most of them?

    This is both an educational exercise, and to see if my thinking is clear. Thanks/


    Statement of Requirements
    *Photography Boat for Boat/Boat & Boat/Shore Photography*

    1- Used power boat of 18~22 feet
    2- Trailerable Utility Runabout
    3- Should fit in standard 24' deep garage
    4- Easy motion in the water, not jerky (will be used as a photography boat)
    5- Large open cockpit usable for picnicing, camping, and as a camera platform.
    5- Inboard engine, outboard if need be, NO in/out drives.
    6- Fast (30kts cruise) in smooth water yet seaworthy enough for short offshore runs at reduced speeds
    7- I like the classic sea skiff style
    8- I love wood, but probably will have to be fiberglass for the following reason
    9- Cheap*
    10- 6~8 passengers with 2 operaters seats plus folding deck chairs for others
    11- range 100nm
    12-




    *I have a figure in mind base on what a boat I though would work went for recently on eBay + what it would have cost to bring it up to sound condition.
     
  2. Ad Hoc
    Joined: Oct 2008
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    Ad Hoc Naval Architect

    Number of personnel on board, legislation (if any) to satisfy, endurance (ie range/distance), accommodation...seats, cabins, galley showers, heads, prop or waterjet, engine manufacturer (if preference) the list is as long as you need it to be.

    Once you have sorted your SOR...then you need someone (NA) to draw up a design on a GA that satisfies the SOR.

    Then and only then can you make informed judgement on, engine selection, material, costs etc etc.
     
  3. philSweet
    Joined: May 2008
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    Location: Beaufort, SC and H'ville, NC

    philSweet Senior Member

    What sort of photography? Underwater?
    There is no such boat that is offshore capable, will do 30 knots, cheap, and fit in your garage. If 15 - 18 knots top end would do, then there are some things you can look at, but they will be fuel burning pigs at speed. What do you have in mind by offshore? Give us an example of a typical excursion.

    ????
    [​IMG]
     
  4. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    If cheap is high up on the priority list, then skip the SOR and find a good used boat, of the length you want, with a relatively shallow V bottom. This can be outfitted to your needs, for a lot cheaper than a new build.

    In a craft of this size all choices will have some motion, depending on sea state. I'm not sure of your aversion to an I/O setup, but they're reliable, quite compared to an outboard, easier and usually cheaper to repair and don't eat up precious cockpit volume with a big box in the middle of a little boat. Of course the outboard is the logical choice, if a bit loud. An inboard (straight shaft) is not the way to go, given your other wises on the list.

    I know of a 24' Pro Line center console for sale a 1/2 mile from here, just a few grand which pays for the worn out outboard, trailer and hull. Drop a new outboard on it, update the controls, electronics and go get her bottom wet in a couple of weeks. She has 18 degrees of dead rise which is more then I'd recommend for a stable platform, but it'll handle deep water at 30 knots with little issue.
     
  5. graywolf
    Joined: Dec 2014
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    graywolf Junior Member

    Thanks for the replies, and on Xmas too.

    What kind of photography. That was in there by implication, but I can see where, it needs to be spelled out or you get Phil's pictured boat when I had something like this in mind:

    [​IMG]

    So boat to boat and boat to shore photography. Hence the desire for a boat that does not have a jerky motion.

    What do I mean by offshore: Probably not really offshore but able to cross inlets and to run outside the coastal waterways for few miles.

    I did specify a "utility runabout" which kind of does away with bunks and galley et al. Although I am aware that some runabouts do have a pair of v-berths.

    The size specified would kind of limit the boat to 6~8 people, I would think, but assumptions are confusing, aren't they.

    Seating? Good question do I want built in seats or just operators seats and some folding deck chairs? The later, I think.

    Engine(s)? Yep, that needs to be specified better, although hp would seem to be something for you designer types to decide upon.

    Range? I doubt that most runabouts carry fuel for more than 100 miles or so. I am I wrong?

    As I said I wrote those up to check my thinking. And as an educational model. Not just for myself, but for other readers since you guys are always talking about a SOR, and I am sure not everyone knows what that means.

    I will go through it again putting the changes based on the above in italics.
     
  6. graywolf
    Joined: Dec 2014
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    graywolf Junior Member

    My aversion comes from old ones being a nightmare to get parts for and repair. I am sure new ones will not fall apart before the boats warranty runs out, but after that I consider them to have all the bad points of outboards and inboards.

    I admit to being old, but inboards I understand and know how to fix. And, that motor box makes a nice picnic table and a nice place to stand and shoot photos from.
     
  7. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Well, finding an inboard compared to I/O's or outboards will be difficult to say the least. I/O's are as reliable as anything else, assuming reasonable care and it's a major brand, that isn't going to be out of business in a few years.

    There are lots of plans for sea skiff hulls, though again, I doubt you'll beat refurbishing a 'glass utility, compared to a new build. If simply a mental exercise, have a look at some of Atkins designs (atkinboatplans.com), there's a few sea skiff and sea bright (which would also be well suited, if you can live with mid 20's speeds) designs to choose from.
     
  8. philSweet
    Joined: May 2008
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    philSweet Senior Member

    Try to bum a ride on an '80s - '90s Shamrock open fisherman. They have a good rep and there are always a few around to be had. Could go older too, they have a long history.

    http://www.powerboatlistings.com/view/30231
     

  9. Pericles
    Joined: Sep 2006
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    Location: Heights of High Wycombe, not far from River Thames

    Pericles Senior Member

    Walter Baron's version of a Simmons Sea Skiff has the benefit of an outboard well.

    http://www.oldwharf.com/ow_simmons.html

    http://www.oldwharf.com/ow_sss_underconstruction.html

    http://www.oldwharf.com/ow_sss_photos1.html

    Build a housing & hatch over the motor for quietness & protection. View Salty from Nexus Marine.

    http://www.nexusmarine.com/salty.html

    NM's reasons for outboards:

    Outboard power
    We chose outboard power for this boat for several reasons:
    First, outboard power enabled us to design a trailerable 29' boat that will do almost 20 mph on 60 horsepower and sell for much less than other custom 29' boats.
    Second, if fuel costs go up you can easily repower with whatever the latest thing in motors might be. Diesel? Fuel cell? Electric? We know that industry responds to demand. There will always be an appropriate motor for this boat. Ten horsepower is really plenty of power for this design.
    Third, when you tilt the motor up, there's no metal in the water, so no corrosion. Again, low maintenance.
    Fourth, outboards are light and cheap to install.
    Fifth, because the bottom is almost flat at the transom, the boat will take the mud upright with the motor tilted up. Berthing costs can be zero if you live in an area with some shallow bays. That might also be important in the sustainable boating future. And this boat is easily trailerable. That's already important and can only become more so.
     
    Last edited: Dec 26, 2014
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