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Thread: Dory atability

  1. #1
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    Default Dory atability

    I have read, mostly in this forum, the instability of dories. I know that they are nervous boats as far as primary stability, but I have read that the second stability makes them a very seaworthy boat. The latter makes sense since they have been used so often as work boats and lifesaving boats. I have read also that building a lightweight dory destroys its stability. I am not sure that I am reading from actual dory owners. Can someone give me the lowdown. I love the look of the boat and want to be one.
    Last edited by graham641; 06-04-2021 at 03:52 PM.

  2. #2
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    Default Re: Dory atability

    Working dories were intended to be filled with fish for ballast as soon as.
    Classic dories have very narrow bottoms and so do need to sit down in the water to pick up water plane area. Swampscott's and so on have very flared garboards and flam in the topsides to increase water plane width and hence stability.
    It really is quite difficult to build an ugly wooden boat.

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    Default Re: Dory atability

    I owned a Bolger light dory (Gloucester Gull) for a while, it was very tippy until I was seated, then it was pretty stable. Pretty much a boat for one person, but fast and fun to row. I haven't tried one myself, but understand that John Welsford's light dory is also a good performer.

    Jamie

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    Default Re: Dory atability

    Another definition is: Dories were the most seaworthy boat that could be built quickly and cheaply and be stowed stacked one atop each other on deck. It's shape a reflection of those needs as much as for seaworthiness. It's also notable that they were manned by experts ( and in a time when life was bought more cheaply than today.)

    Over time , there developed many flavors of dory, with a number based on traditional designs but intended for the recreational builder and user. Among these you will likely find a suitably stable boat.

    Kevin
    Last edited by Breakaway; 06-04-2021 at 05:11 PM.
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  5. #5
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    Default Re: Dory atability

    I have looked at a lot of plans. The Bank dory looks to be the worst with very little secondary stability. Some stability looks to come from the angle of the deadrise. The secondary stability comes in when the boat is heeling and it should behave like slow sailing ship like the Mayflower. At least that is the way it looks from a newbie point of view. I am sure that if it is lightly loaded and you are rowing within a sharp angled deadrise then you would have your hands full. It would act like a canoe, only when it heels would it show its stability. I suppose that is why a heavy load makes the boat feel more stable. I am asking this because I would like to sail the backwaters of the outer banks which is fairly smooth but I know that I will try to fish in the rough waters around Cape Hatteras.

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    Default Re: Dory atability

    Thanks, that sounds about like what I suspected.

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    Default Re: Dory atability

    I guess my head is in the Winslow Homer painting.

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    Default Re: Dory atability

    I am looking at the lines of a 16 foot boat based on the Swampscott design. It is in one of Gardner's books. I looked at the Beachcomber-Alpha but the offsets are completely wrong and, being a newbie, I do not trust myself to clean up the offsets.

  9. #9
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    Default Re: Dory atability

    Swampscott type dories are much improved for use as a small "yacht". A great boat for sailing and playing within sight of the shore. Some designs are better than others.
    I've had some considerable experience with Banks dories and would not (today) recommend one unless the use was something similar to dragging 100's of pounds of fish over the rail in open water. They have a good reputation, but I think that is largely earned by the very capable sailors and fisherman that made their living in one. They are a completely different boat when deeply laden, but empty in a tough chance your best bet is to lie on the floor near the bow and hold on tight.

    Which version are you looking at?

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    Default Re: Dory atability

    I've a semi Swampscott, three plank sides, a curve only for the sheer strake, TIPSY is her name and she is. But stick 50 pounds in the bottom and things firm right up. And I keep 5 gallons of water in her to use for fore and aft trim. At the same time I can roll her right down to the gunwale and she'll stay there.

    When I was at Mystic we used to run dory races in Banks style dories with a 180 turn. I've seen gung ho rowers on the turn roll themselves out of the boat with the dory not taking on any water.

    In a study of peapod stability for contrast we ran the curves for a single person banks dory. Not something you want to roll down to slide a soaked trap aboard.

    People forget that even a Banks dory running with out fish in it had maybe 200 pounds of gear. A couple of trawl tubs get to 150 then there is the other gear.
    Ben Fuller
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  11. #11
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    Default Re: Dory atability

    I have read that the Bolger light dory is best in class.

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    Default Re: Dory atability

    I was thinking of a lead or steel keel. How did the semi Swampscott behave in seas?
    Last edited by graham641; 06-05-2021 at 02:17 PM.

  13. #13
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    Default Re: Dory atability

    Gardners book Building Classic small craft shows a 16 foot dory based on a Swampscott looks good at the moment. I like the beachcomber Alpha but in Gardner's The Dory book has bad numbers in the offset. I do not trust myself to recreate the offsets. It would be an interesting challenge though. I do tend to overestimate my skill levels. I get quickly over my head. I originally was going to build a prospector canoe for poking around the Amazon river but politics and military are making me consider North Carolina. Home again. I may build it yet. I am considering the town of New Born. It is along the Nuese river. Upstream is freshwater fishing, downstream is salt. It is protected water all the way to the outer banks. Knowing myaelf, I would try to handle the surf on the ocean side.

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    Default Re: Dory atability

    Do you intend to sail it?
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    Default Re: Dory atability

    Quote Originally Posted by graham641 View Post
    I was thinking of a lead or steel keel. Haw did the semi Swampscott behave in seas?
    If you add an appendage (keel) on a dory you run the risk of it "tripping" rather than rolling away from danger. I think it no longer behaves like a "dory".

    I have been in a light banks dory in large seas as it was sliding sideways down the face of a breaking wave. This happened more than once, seemed to be the norm and it would slide along until it tossed the gear and occupants out and scooped up about a half a load of seawater. Then it would settle down, sit low in the water and wait patiently like the faithful steed for you to swim back and clamber aboard.
    This was in rather severe north Pacific winter conditions maybe 20 foot waves, and the water was cold.

    (I lost two good friends off Cordova, Ak in a banks dory modified with a keel under similar conditions. One was found dead (of exposure) in the boat half full of water, the other went missing. A competent father and son team that had been working open boats in the gulf of Alaska for their entire lives, the boat was burned on the beach)

  16. #16
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    Default Re: Dory atability

    Be very wary of adopting a traditional workboat design that has been developed for a very narrow range of uses and working conditions for use as a pleasure boat in waters and conditions that it was not developed for. Until you fully understand the idiosyncrasies of the boat, you do not know where and when it will reach out and bite you in the azz, often very hard.

    Be very, very wary of making changes to a traditional workboat design that has been developed for a very narrow range of uses and working conditions to make it into a vessel to operate in a different role. Such boats were incrementally developed by very experienced users and builders over a long time - often generations - and making uninformed alterations can have profound impacts on the boat's performance, and even on its safety.

    The simpler a traditional boat type is, the greater the impact of what are seemingly minor changes. In reverence to traditional Banks dories, a change in the amount of rocker in the bottom - as small as a mere inch - can change the boat from an agile and easily-driven boat into a slug.
    Hope for the best, but plan for the worst.

  17. #17
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    Default Re: Dory atability

    The steel keel idea was to gain initially stability for sailing. Not for rowing in seas, especially the ones that you describe. I am not sure that I would consider a banks dory in the same class as the round sided dories. They do not look like they would have the same secondary stability as a round sided dory which keeps the center of gravity vertical to the center of flotation. What small craft design would handle 20 foot breaking waves? You obviously qualify as one of the aforementioned skilled sailors. In those kinds of seas I may as well just jump into the waves and hope my life preserver would float me to safety before I died of exposure. I am sorry to hear about your fellow sailors. You guys are the toughest of all mariners.

  18. #18
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    Default Re: Dory atability

    Yes, I understand that the evolution of dories is not just a random change. That is why I chose not to try to build the Beachcomber alpha which I do not have the correct offsets for. Maybe someone has corrected the offsets shown in Gardner's beachcomber alpha design. I would like to hear from them. It was recommended that I build a half hull model to see what the fair lines should be. I do not trust myself that I would know a fair line from a random line. I only know about dories from reading with absolutely no experience.

  19. #19
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    Default Re: Dory atability

    I see the dory much like a canoe as far as primary stability. If you step off center in a canoe, it dumps without warning. I understand that the round sides of the dory provide the secondary stability to make it seaworthy.

  20. #20
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    Default Re: Dory atability

    Yea, it is my intention to sail it in the protected waters behind the outer banks in North Carolina.

  21. #21
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    Default Re: Dory atability

    There are very subtle and not so subtle differences in a dory built for sailing, and a dory built as a low power powerboat (rowing)
    A banks dory does not sail well, and if sailing is your intention it will likely be a disappointment.
    Do your homework and you will be fine. Post your selections and you will receive competent critique here, the trick is going to be sorting through opinion vs. experience.
    There are accurate offsets out there, but whatever boat you are going to build, you should (will) loft it, at least the basic lines, which will " fix" any inaccuracy in the shape. This is normal procedure. With the advent of epoxy glued lap plywood a sailing dory can be a capable and trouble free boat.
    Here is a good commentary on my favorite " dory" the Indian : https://www.boatbuilding.xyz/boat-de...cing-dory.html

  22. #22
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    Default Re: Dory atability

    If sailing is important, also consider the dory-skiffs.
    Ben Fuller
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  23. #23
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    Default Re: Dory atability

    From WoodenBoat: John Dory. Beautifully-drawn plans of a Swampscott with a multitude of options (rowing version, multiple sail versions, heavier workboat construcion, etc.). Very traditional in appearance. There's also his book on how to build that construction type (in English).

    https://www.woodenboatstore.com/coll...cott-john-dory

  24. #24
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    Default Re: Dory atability

    I have sailed my Northeastern Dory on the Chesapeake many times. Although this is not a traditional boat, but rather a modified Swampscott she is stable and easy to row. My one capsize was due to the captains error. I fouled the main-sheet in a tack and over we went.. Recovery was quick and easy.
    Skip

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  25. #25
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    Default Re: Dory atability

    67C7906E-9FD0-4327-B974-CFC38ED77262.jpg
    My duck punt ain’t nothing but a low sided dory with very little rocker and flare.

    She sails a treat, with no board nor rudder.

    9D3AD6EA-D841-40AD-B923-D9514FE9BEAB.jpg
    One of my pirogues that is essentially a tiny banks type dory.

    In my very limited experience, the boat itself provides a small amount of the “seaworthiness” and/or “capability” of a hull type/shape; that is, simple hull forms can withstand a lot, and complicated hull forms can kill you just as dead. The person/boat matrix is what makes something capable, or not; within limits, of course.

  26. #26
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    Default Re: Dory atability

    My experience is with three major dory types:

    Working "Grand Banks" dory - Very poor boat totally light but very seaworthy and easily rowed at low displacement speeds (3K) when laden. Maybe sail downwind.

    Chamberlain Gunning Dory - Most versatile as rowed well light or laden, sailed OK, enough form stability that I could walk the gunnel or stand on the garboard, lay a long line over the oarlock, and rock back to lift with little strain on my back drawing in the fish. Great surf boat.

    Glouster Gull - best rowboat in this universe. Phil's ticket to heaven.

    Yeah they are all 'dories' and for sure they are wildly different boats. If anyone thinks they are the same or even a little similar, they've not rowed.
    Last edited by Ian McColgin; 06-06-2021 at 11:30 AM.

  27. #27
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    Default Re: Dory atability

    Having been in dory to row for an hour, and spent 70-80 hours in a Flattie skiff last summer, I feel it would be an easy choice as to which I would choose to be in for fun-the skiff. I think most of the local work boats were some type of sailing Flattie/sharpie.

  28. #28
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    Default Re: Dory atability

    Quote Originally Posted by Ian McColgin View Post
    My experience is with three major dory types:

    Working "Grand Banks" dory - Very poor boat totally light but very seaworthy and easily rowed at low displacement speeds (3K) when laden. Maybe sail downwind.

    Chamberlain Gunning Dory - Most versatile as rowed well light or laden, sailed OK, enough form stability that I could walk the gunnel or stand on the garboard, lay a long line over the oarlock, and rock back to lift with little strain on my back drawing in the fish. Great surf boat.

    Glouster Gull - best rowboat in this universe. Phil's ticket to heaven.

    Yeah they are all 'dories' and for sure they are wildly different boats. If anyone thinks they are the same or even a little similar, they've not rowed.
    Ian, do you think it would be possible to scale up Phil.s dory to make it work for two persons?

  29. #29
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    Default Re: Dory atability

    Thanks everyone for your input. I learned much about what I do not know. All of your advice and experiences have given me much to think about and learn about.

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