Flat bottom boats as bluewater cruisers

[mako]

How capable are flat bottom boats like sharpies, dories, etc., for bluewater cruising? Assuming they are designed for that purpose, heavy enough to carry necessary stores, etc.

Also noted that dories have highly sloped topsides, not very vertical, perhaps this leads to more tenderness or roll acceleration.

Flat bottom boats are horrible pounders in small planing boats, but as a displacement, slow speed cruiser, that is different.

Thanks.

[Suijin]

Capable is relative term. At a minimum they are not going to be very comfortable in a big swell. While the flatness provides roll stability in a smaller chop it becomes a liability in a bigger seaway. Much of it comes down to how much ballast you have down low.

I’ve done some ocean racing in purpose-built high performance sleds, designed to plane off the wind, with very flat bottoms. But they also have 10’ keels. To say that they are uncomfortable would be a dramatic understatement.

[GordMay]

From “Facing Aft: Anecdotes and Essays on Cruising Under Oars” ~ By James C. Sand
Dories (Pg 62) ➥ https://books.google.ca/books?id=gu7...bility&f=false

Scroll back to page 60.

[Scout 30]

Once a Sharpie is heeled, which happens pretty quickly, it's chine becomes the keel & it's no longer a flat bottomed boat. When well designed & built they are remarkably seaworthy.

[nuvaslacker]

Benford dories have been used successfully for bluewater for some years. Many are junk rigged and equipped simply.

[nortonscove]

Originally Posted by Scout 30

Once a Sharpie is heeled, which happens pretty quickly, it's chine becomes the keel & it's no longer a flat bottomed boat. When well designed & built they are remarkably seaworthy.

I was about to respond with the same until seeing this post. Think of the needs of the Grand Banks dory. Very stable under the worse conditions.

[scallowayuk]

Harry pidgeons islander was fairly flat bottomed.if thats what you mean.she did ok.

[TrentePieds]

In WoodenBoat #43, November/December 1981 you will find a wonderful article about the Sea Bird yawl designed in 1901 by Thomas Fleming Day. The basic design was an evolution of the Chesapeake Skipjack still in common use when SeaBird was designed. In 1911 TFD crossed the Atlantic in the prototype SeaBird.

Here: https://sailboatdata.com/sailboat/sea-bird-26-1909 you will find her "numbers", as well as arrangements drawings and the sail plan.

The sail plan shows a sail sadly missing in modern boats which for reasons well known to most of us, but to the regret of some of us, possess rather too many of the traits appropriate to racing boats, and too few of the traits appropriate to cruising boats. That sail Day and his crew called, with affection, their "foolish sail". It was a square sail set on a yard and it served the purpose that in modern boats is served by that intractable total PITA called a spinnaker.

The way you ask your question predisposes me to think that you are not yet thoroughly familiar with the elements of yacht design. I therefore commend to you the classic Skeene's Elements of Yacht Design by Francis Kenney. That book will take you a very long way towards understanding why boats loook the way they do, why they have the shape they have.

Please have a look at the data sheet for the SeaBird. Note particularly that she has a Sail Area/Displacement ratio of 26.65, which is MUCH higher than that number for a "modern" boat. Note also that she has a Displacement/Length ratio of 170.66 which is MUCH lower than that number for a "modern" boat. That these numbers are what they are - so different from modern practice - is what disposes the sailplan toward the yawl rig rather than a plain sloop rig. This in turn has implications for the boat's behaviour at sea, and the way you handle it. Among other things, it means that the boat isn't much as a racing boat, but she is an easily handled cruiser. Note also that she is a gaff rigger, i.e. she has a low aspect ratio rig as opposed to the high aspect ratio rig that is appropriate for racers. It is this fact (that the rig is low aspect, i.e. has a Centre of Effort disposed not too high above the Centre of Flotation, that enables her, in conjunction with her "flat" bottom (low deadrise) and "hard" chine) that enables her to stay on her feet and sail well in a hard blow.

Now, if you let me :-), I could cary on - and on. But my purpose is only to show you that your question, as asked, is not really amenable to a simple binary answer such as "flat bottoms are good" versus "flat bottoms are bad". But that you are asking the question at all means that you are off to a good start :-)!

Do get Francis Kinney's book. It is well worth the few bux it costs. Beyond that, there is literature that will take you the rest of your lifetime to internalize. But when you done that, you will know the answer to the question you asked :-)!

You might like to know that in my callow youth I actually did own a SeaBird. You might also like to know that if it were not so difficult because a previous owner of little understanding rigged TrentePieds with one of those god-forsaken mast-mounted roller furling devices, I would give her a "foolish sail". They are the cat's pyjamas for a cruising man!

All the best.

TrentePieds

[Siberian Sea]

My Cal-40 is somewhat flat bottomed. Yes, it has a large fin keel but the hull itself is very flat. Hull speed it’s about 7.5 kts but I often can exceed this in large following seas because it starts to surf on the waves. My top speed has been 19.5 kts as recorded by the GPS for over one minutes time. It’s my opinion that the flat bottom Cal-40 is very seaworthy so I must assume that there are many other similar vessels the same or even better.

[Junk Viking]

Originally Posted by nuvaslacker

Benford dories have been used successfully for bluewater for some years. Many are junk rigged and equipped simply.

Benford dories are perfect ocean cruisers, as are many other hard chined designs like the German Reinke

My own little tub is a Reinke Super 10 (34') also sporting a schooner junk rig.
I get a huge usable living space with a raised settee with 360 vision for safety, comfort and social life in the anchorage.

IMO the modern schooner junk rig is the most safe, easily balanced and reefed, versatile and robust rig for bluewater cruising.
I constantly wonder why more serious and experienced cruisers don't end up opting for the junk.

Reinke Yacht

[Paul Howard]

Check out the Tom Colvin designs for dories, sharpies, etc. that are very seaworthy.

Also, the contemporary French aluminium designs with centreboards have a mid-plate that is flat athwartships with enough rocker to allow for a rudder.

[hpeer]

As to Benford Designs I would direct you to a delightful book by Annie Hill, Voyaging on a Small Income. Among its many attributes it discusses the design and characteristics of their flat bottom dory live aboard sailboat, a Jay Bencord design. They spent many years crossing back and forth across the Atlantic before heading South to Brazil and then the Fauklands.

Check out this stellar beauty

https://www.yachtworld.com/boats/200...owse%20listing

And a much more modest example.

https://m.sailboatlistings.com/view/77719

[Diesel Bill]

Back in the mid to late 1970s I owned a 26' on deck St. Pierre style dory. It's a larger version of a banks dory. I can swear to the sea keeping ability of this style of vessel.
Although limited in size and creature comforts it was an amazingly safe boat. Used for cod fishing up on the Grand Banks and manned by 2 men per boat. From what I have read no case of any man lost at sea.
My boat was decked over with fore and aft cabins and small center cockpit. Ketch rigged. Very tender initially then became very stiff when hard pressed. The more load carried the better it would ride. Tended to pound if pushing into the weather but would surf downwind in large swells. Not what I would call a blue water cruiser but a safe boat if caught out in bad weather. I used it for coastal cruising San Francisco to Santa Cruz. It was small enough to tuck into any small nook or cranny to take shelter. I wouldn't want to cross oceans with it but I believe in the sea worthiness of the design.

[roland stockham]

I have sailed a 45ft Hillyard built in the 1930's as a cruising boat. It was classed as a 'barge boat' with a fairly flat bottom, schooner rig with a square sail on the foremast and fisherman plus staysail between the masts. It sailed very well off the wind but you definitely could not point much above 50deg. Built when 'gentlemen did not sail to windward'. Would be great for coastal cruising and fine for downwind tradewind crossing but would not be good for example, on a west east Atlantic crossing.
Having said all that if you look at most modern 'cruising' boats the have a canoe hull which in my view is pretty much a flat bottom. Makes them fast downwind and initially stiff upwind but they slam like a pig, are difficult to hove too and need huge amounts of input in rough conditions so, as always, you need to match the boat to what you want to do.

[picklesandjesse]

[QUOTE=hpeer;2818323]

Check out this stellar beauty

https://www.yachtworld.com/boats/200...owse%20listing

I've been watching this boat for 6 mths. Would love to own it as it suits my old age !!! Just short a few hundred thousand $$$$$. I buy a $2.20 lottery ticket every 2 mths just in case. I figure $12 a year is an OK gamble. Some people in this country are crazy and might spend more than that each week.