Design by Karl Stambaugh Commentary by Joel White

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Over the past few years, America has experienced a rebirth of wooden boat building. There is no question that this is true, but much of the coverage in the yachting press might lead one to think that this renaissance is limited to a few extremely elegant and expensive yachts built for those with unlimited funds and time to indulge in such hobbies. The glitz and glitter have always received more media attention than the simple and mundane — yet the news is perhaps more interesting if one digs a little deeper for the facts.

A healthy amateur boatbuilding effort is turning out dozens and dozens of small, good-looking, useful boats made from forest products. One has only to turn to the "Launchings" column in each issue of WoodenBoat magazine to find the evidence. There are, in addition, many professional shops building a variety of boats on custom order, and employing a surprising number of craftsmen. It would be a mistake to fall into the trap of thinking that only the rich and famous are having wooden boats built.

As a result of all this activity, there are now a number of designers turning out boat plans that cater to this somewhat invisible market — boats that can be easily built of non-exotic materials, boats that will not break the family budget.

Designing such boats is neither easier, nor does it require less skill than designing the gold-plater. It is, in fact, probably more difficult. In addition to creating a safe and useful boat, the designer must give constant attention to construction that properly utilizes low-cost materials while minimizing the hours needed to complete the project. Bahama Mama is a perfect example of such an effort.

This little cruising ketch is built from sheet plywood, using multiple-chine construction, and fiberglass tape and epoxy to join the various sheets of plywood together at the edges: tack-and-tape is a good description of the process. Bulkheads are part of the construction setup, and are integral with the structure.

Karl Stambaugh designed Bahama Mama in collaboration with Gary Clements of G.F.C. Boats. The designer describes her as "a capable coastal cruiser to voyage beyond local waters and explore the backwaters when she arrives. All in a package within the means of time and dollars of most with the desire to live the cruising lifestyle." There, doesn't that thought get your blood moving?

Let's start by looking at the sail plan. The simple ketch rig is of moderate size, and is in no way unusual except in how well it seems to fit the hull below. The mizzen, as with most ketches, lands smack in the middle of the cockpit, passing through the bridge deck. Yet, Stambaugh has made the bridge deck wide enough to give easy access to the companionway forward of the mizzen, and to allow the on-deck crew to stretch out in comfort. The 380 square feet of sail is divided in such a way that the center of effort does not change much under various sail combinations. A large genoa on a roller-furler is offered as an option to increase sail area when the wind is light. The simple box-section spars are well stayed, and the stay between the mastheads ensures that the mizzen will remain in column when sheeted in tightly. All working sails show reef 100 —

Particulars Bahama Mama

LOD 30'0"

LWL 27'6"

Beam 9'6"

Draft (cb up) 2'0" Draft (cb down) 5'6" Displ (light) 9,000 lbs Displ (full) 11,000 lbs

Sail area (working sails) 380 sq ft

The simple ketch rig fits this hull well. Although the mizzenmast lands on the bridge deck, it doesn't spoil access to the companiomvay.

The simple ketch rig fits this hull well. Although the mizzenmast lands on the bridge deck, it doesn't spoil access to the companiomvay.

Tahiti Ketch

In Arrangement No. 2, Stambaugh

Karl Stambaugh Boat Design

In Arrangement No. 2, Stambaugh

Bahama Mama Sailboat

Bahama Mama's flat bottom reduces draft and provides a solid stance when she takes the ground. has moved the toilet forward and added a quarter berth on the port side.

Karl Stambaugh Boat Designs
Arrangement No. 1 shows a toilet room aft to port, with the galley opposite to starboard.
Karl Stambaugh Boat Designs

points, one set in the mizzen and the jib, and two for the mainsail. Shoal-draft centerboard boats need to reef more often than those with deep ballast keels.

Notice what an attractive profile Bahama Mama makes, with her strong sheer, low freeboard, and cleverly proportioned house. Stambaugh has a very good eye.

The lines plan shows the unusual shape of this little boat. Let's imagine that she had been designed as a single-chine hull with quite a lot of deadrise, and much rocker to the keel. Then, imagine that 2 feet below the waterline we drew a horizontal line, cutting off the deep center V-section, and producing a flat bottom parallel to the waterline. Forward and aft of this flat bottom, the V shape continues upward to meet the stem and stern. This one stroke of the pencil changed her from deep-draft to shoal, keel to centerboard. The straight section lines are dictated, of course, by the sheet-plywood planking. Stambaugh has managed to keep most of the twist out the forward and after sections for ease of planking.

The boat's displacement is given as 9,000 pounds light and 11,000 pounds loaded with cruising gear and stores. With her long waterline length of 27 feet 6 inches, this gives a displacement/length ratio of 193 light and 236 loaded, surprisingly light for so small a cruising boat. This hull should be seakindly, buoyant, and, because of her long waterline and moderate displacement, reasonably fast.

Bahama Mama is what I would call a unified design. By that, I mean all elements of the design contribute to the overall purpose of the boat, and work towards the desired end result. For example: the straight, flat bottom allows the boat to have shallow draft. It also allows the boat to take the ground and remain completely upright while doing so. One of the problems with such boats is how to hang the necessary ballast keel. Stambaugh has solved that in the most simple and direct way — by pouring a mixture of cement and scrap iron on top of the flat bottom to a height of about 4 inches, using rebar through the floors to lock it all in place, then laying the cabin sole over all. Marvelous! He recommends a minimum of 5,500 pounds of ballast, which will give a 50 percent ballast ratio in the loaded condition. A stability curve that came with the plans shows Bahama Mama having positive righting arm to more than 120 degrees of heel, unusually good for a shoal-draft centerboarder.

Two interior layouts are included with the very complete plans package of 11 sheets. Both are simple and well thought out. Arrangement No. 1 has a toilet room aft to port, with the galley opposite to starboard, settee/berths each side amidships, and a pair of V-berths forward. In Arrangement No. 2, the toilet is forward to port with a larger berth to starboard, settee/berths amidships again, and a quarter berth aft to port in place of the toilet room.

The centerboard trunk starts at the bulkhead at the after end of the cabin and runs forward about 7 feet into the cabin, dividing it along the centerline to a height of 28 inches off the sole. This gives the cook something to lean against or sit upon, yet is low enough that it does not visually interrupt the cabin space. The single centerline companionway opens onto matching port and starboard ladders, offering a choice of routes when going below.

Cabin headroom varies from 5 feet 4 inches forward to about 6 feet aft under the companionway hatch — pretty darn good for a small shoal-draft cruiser. The toilet space is quite limited in either layout. In Arrangement No. 1,1 would be tempted to sacrifice some width on the port ladder and add it to the toilet room. Except for the V-berths, the bunks are a bit short for my taste (about 6 feet). But both arrangements make the most of the available space, and when cruising Bahamian waters, most of one's time would be spent in the large cockpit, under a big awning when not underway.

Bahama Mama's construction is mostly sheet plywood of various thicknesses, easily obtainable from the local lumberyard. The flat bottom is two thicknesses of %-inch ply, glued together. The lower planking strake is two layers of /2-inch ply, glued together. The upper planking strake is %-inch plywood, with a 1 VS-inch fir or mahogany sheerstrake glued on top. The deck is /2-inch plywood covered with Dynel and epoxy. Plywood bulkheads are lofted and shaped before setting them up on the bottom plank, and the remainder of the planking is wrapped around these bulkheads, which act as construction molds — all simple and very strong.

The box-section spars are wood: spruce glued with epoxy. The mainmast steps on the cabintop, and the mizzen passes through the bridge deck to the cockpit floor. Standing rigging is specified as 1 x 19 stainless-steel wire, and the running rigging is Dacron rope. No skimping on materials here, and properly so, the integrity of one's rig being crucial to safe and enjoyable cruising.

Auxiliary power can be either an outboard in a well, or, for those desiring a more efficient inboard unit, a small diesel is shown under the bridge deck. There is room for 50 gallons of fuel in two tanks under the cockpit seats. Stambaugh also calls for 60 gallons of fresh water in plywood tanks under the main cabin berths.

By now you probably realize that I like this design a lot. I think it fills a need for a simple, inexpensive cruising boat that can be built by a handy amateur, or put together quite reasonably by a professional shop.

Stambaugh estimates that 2,000 hours of labor would be required to complete Bahama Mama, and $10,000 to $12,000 [1994] would do it for basic materials (I think he might be a bit low on material prices). In any case, these figures add up to a very affordable boat.

Plans for Bahama Mama are available from G.F.C. Boats, 490 Hagan Rd., Cape May Court House, NJ 08210.

Karl Stambaugh can be reached at 794 Creek View Rd., Severna Park, MD 21146.

Bahama Mama

Bahama Mama

Karl Stambaugh Boat Design
The 4-inch-thick ballast of poured cement and scrap iron is secured with rebar through the floors.
Paul Gartside Boat DesignJoel Boat DesignKarl Stambaugh Boat Design

Bahama Mama goes together stitch-and-glue fashion with epoxy and fiberglass fillets joining plywood panels.

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  • amalda
    Is no question that this?
    7 years ago

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