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Mollusk 01-15-2008 09:20 PM

shallow draft pros and cons
 
I just bought a morgan 321 shallow draft. It draws 4. So far it has performed well under San Juan winter conditions. I had it out in 30 kts with 4' bay chop- no problems. The general mentality up here as far as draft goes is: the deeper the better. There are plenty of deep anchorages and much fewer sand bars than in the east or the gulf. I just want to hear what some others think as far as pros and cons of shallow draft go. Is the stability altered when you get into some really heavy weather? How are they in the open Pacific?

Faster 01-15-2008 09:35 PM

Someone like Jeff H can give you a much more technical review, but from a PNW perspective there's not a real need for shoal draft, as you say.

However, you have one so:
You will have an advantage in many anchorages in that you can "sneak" in behind the pack and anchor tighter to the beach of the end of a cove - this will be especially handy in the busy summer season. If stern tying, with caution you can tuck in closer and maybe get out of a breeze or current. You'll still need to keep an eye on the tides, of course.

As far as performance goes, there will be a bit of a penalty, mostly in progress to weather. Your numbers may well look OK, but if you are sailing upwind in close proximity to a similar boat with deeper draft, you will probably find you lose ground on each tack as you will suffer more from leeway. (Assuming both boats equally well sailed, of course)

At sea it will likely be a less noticeable difference unless, again, you need to fight your way to windward, or "claw" your way off a lee shore somewhere....

Many "shoal" versions carry some additional ballast weight to offset the righting-arm loss, so depending on design there may not be a huge difference in "stiffness".

sailingdog 01-15-2008 09:46 PM

It depends on the boat. If you're talking about a monohull sailboat, deeper drafts tend to be more stable than the same design with a shoal draft.

However, you can also get shallow draft via a multihull... in which case the Pacific was explored by shallow draft boats a long, long time ago. The Polynesian Islanders explored and colonized much of the southern Pacific in multihulls.

One major advantage of shallow draft boats is that you have more areas in which you can anchor. This becomes a huge benefit if you're trying to hide from a hurricane or storm.

A very shallow draft boat can go up small creeks or rivers or into very shallow bays, where the storm's effects will be severely blunted. It also means you can get into more harbors, without necessarily waiting for the tide.

Tumblehome32 01-16-2008 01:42 PM

It has more to do with the angle of vanishing stability and keel side area, not just draft. I would think a lot of Morgan 321 owners could give you the best advice on real world conditions.

chucklesR 01-16-2008 01:47 PM

With no lead mine hanging below my Gemini, a wave passes under it and transfers no force to the non existent keel- so in monster waves my boat just slides on the face rather than tripping over a rock like a mono does.

Shoal draft boats generally carry more ballast than their deep draft sister ships, that is designed in to it to compensate for the higher center of gravity.

SailorMitch 01-16-2008 02:39 PM

Concerning whether a shoal draft boat will survive in blue water -- Carleton Mitchell's famous Finnistere was a center-boarder designed by Olin Stephens. Finnistere won consecutive Bermuda races back when.

In sum, yes a deep fin is usually better, but that doesn't mean a shoal draft boat isn't seaworthy or can't go to weather.

Disclaimer -- I sail a P-33-2 with a winged keel that draws 4'2" and I haven't died yet. :)

seabreeze_97 01-17-2008 12:06 AM

Intrepid, the Bristol 32 originally built for Ted Hood, has no problem plodding the Pacific between Hawaii and Japan, and they also do well in the Atlantic. While there was a centerboard option, the majority of them were shoal draft at 4 1/2 feet.

Nottoway 01-17-2008 04:16 PM

Nottoway, my Bristol 39 (40) centerboarder is not unlike Finsiterre, drawing only 4' with the board up. In rough seas, pulling the board up makes the boat less resistent to waves--it slides sideways a little more easily resulting in a less jerky motion. The board is a maintenace headache, however. It broke off in mid-Atlantic and a new one had to be built in the Azores. (The fiberglass board was built with steel re-bar to stiffen it, the re-bar rusted and swelled, weakening the board and rough weather finished it off.) The wire pennant has also broken a few times due to flexing and deterioration where it attaches to the board.


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