Design Contest #6 - Entry 5 click here to read or make an observation about this  article
By Doug Taylor - Bainbridge Island, Washington - USA

Port Madison Proa

Drawings - Statistics - Description - Budget - Bio

Drawings:

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Statistics:

LOA
-
20’-0”
LWL
-
17’-8”
DRAFT
-
11 – ½ “
DISPLACEMENT
-
890 #, loaded, ama airborne
BEAM OVERALL
-
12’-6”
HULL BEAM, DECK
-
2’-8”
HULL BEAM, LWL
-
1’-11”
AMA LOA
-
16’-8 1/2”
AMA VOLUME
-
8 Cu. Ft.
AMA WEIGHT
-
Variable w/ water ballast
S/A
-
150 SF
CONSTRUCTION
-
Stitch & glue sheet plywood
HEADROOM
-
3’
BERTH SIZE
-
6’-6” x 23” x 10”
DISP/LENGTH
-
80
SA/DISP.
-
24 - 25
PRISMATIC COEFFICIENT
-
.69
BLOCK COEFFICIENT
-
.43
BRUCE NUMBER
-
1.22


Description:

BACKGROUND
This Micronesian type flying proa might provide the most boat for the buck, in terms of a fast, seaworthy mini-cruiser. The design shows an asymmetrical hull with a nearly traditional shunting oceanic lateen rig. The combination is service proven, and precludes the need for dagger board/rudder/multiple sail complications. With the hull form providing lift to windward, and the rig right forward, much steering can be by the sheet, except as we approach downwind, for which circumstance a 12 steering oar is shipped. The oar also provides sculling propulsion. Include a canoe paddle in the ship’s gear for light work. Since a wee outboard would bust the budget, planning routes with a tide table, current chart, and wristwatch will be essential. If there is some wind, this cruiser ought to be fast enough to buck most tidal currents found in Puget Sound, though I’d time transiting the Swinomish Channel or Deception Pass, the former with the current, wind direction permitting, and the latter at slack water.


HULLS
This asymmetric main hull construction brings a new slant to the term, “Semi-Vee Bottom.” The pram bows put some buoyancy at the ends, as driving one of these upwind will put the bow down. The beam, a bit chunky for a proa, is about the minimum needed to provide space for a narrow berth within. The ama will be buoyant enough to support a man boarding from that side, because circumstances could make that necessary; and will be heavy enough, with water ballast shipped, to hold the unreefed rig up in a 15 – 20 kt. breeze. The vee of the ama hull will let it hit waves and surface gently.

DECK
A cable at the right tension in a wooden channel/rail, leads the yard foot from bow to bow, over the cabin, pulled with an endless loop of line. Epoxy with graphite powder additive, or a straight stem ball castor, will reduce friction, here. The mast will follow the yard, with passive running stays keeping the rig up at mid-shunt. Although my Micronesian correspondent tells me he’d just go grab the yard, and walk to the other end, even single handed, shunting from the cockpit will keep a Northwestern single hander feeling secure around cold water. I stepped the mast away from the hull, amidships, so that the running stays can loop under the platform on the windward side of the hull, tensioned by a length of fat shock cord. The arrangement of these stays will also provide a little time to scandalize the rig, if caught back winded.

Controls amount to the endless loop at the yard foot, a pair of sheets, halyard and topping lift, and steering oar. The ground tackle, a small (8S) Danforth type would do, will be secured outboard of the plank seat. A nylon rode will lead to the anchor from a bow locker through a rope pipe on one foredeck.

CABIN
This 20’ canoe offers tight accommodations for a cruising sailor. What might have been berth #2 has no mattress, and is the location for a portable galley box/chart/dining table, which rolls or slides toward amidships, and opens like a secretary desk. A propane camping stove, crockery, cutlery, plastic basin, condiments, etc., can be stored here. A large duffel bag at the foot of this non berth is pulled in and out with an endless loop of light line. With the galley and duffel shoved out of the cabin, a canvas lounge chair is unrolled from its storage position at deck level, the lower end tied to the non berth front, a bit like a lee cloth might be. Stowage space under the berth(s) is available for camping gear and whatever. Water will be stored in plastic jugs in the cockpit, under the plank seat, as well as propane bottles, the former due to their weight, the latter for safety.

An MSD is stowed and used under the utility berth. One shelf adjacent to the companionway will be for oilskins, the other for sailing gear, like USCG requirements, gloves, and any electronic or optical devices afforded. The lee side shelf could hold books, thermos, camera, etc. Running lights should be portable battery operated units. As the smallest deep cycle 12 volt battery is around 50 #, it would be prudent to use portable electrical/electronic stuff, each with self contained batteries, and to carry spares.

CONSTRUCTION
To build this boat, I will get expansions for the hull panels with half models, and proceed in the regular stitch and glue manner, from the bottom up. I will use ¼” plywood predominately, with ½” in flat places, like the cabin and cockpit. I would lay the deck with the outer grain of ply running athwartships for stiffness. Plexiglas cabin windows can be included as shown, or not. Outrigger poles, aka’s, are of Douglas fir 4x4’s, secured at the deck and platform cockpit with bolted brackets. Telescoping aluminum tubing would be nice, but is outside the budget. These wooden akas are demountable for trailer transport.

The spars and sweep(s) are laminated from Douglas fir stock, tapered or formed with a bandsaw, and rounded by hand.

Budget:

Plywood, Luan Aquatex,  
        13 sheets ¼” 4x8 @ $49
$650
        2 sheets ½” 4x8 @ $85
$170
No. 1 or 2 Fir, spars, track, akas 100 BF, resawn
$200
Epoxy 4 gal
$300
Fiberglass tape, 50 yd ea. - 4" & 6"
$ 75
Fiberglass cloth 30 yd. - 6oz x 50”
$180
Paint Latex exterior
$50
Foam mattress open cell
$20
Lights, batteries  
$50
Galley box scrap ply, paint
zip
Ground tackle  
$170
Rigging & blocks  
$240
Provisions for 2 weeks  
        Fuel 20 propane bottles
 
$40
        Food
 
$105
        Beverage
 
$20
Propane catalytic heater  
$45
Polytarp sail  
$40
Miscellaneous  
$75
Portipotti Thetford 962  
$70
TOTAL  
$2450

Budget Notes

This budget actually accounts for new stuff, and could be greatly eased by scrounging. I, for example, have a stack of rough milled Douglas fir by my house. Getting the plywood might involve a trip to British Columbia. As for the paint, I have read from more than one source that good quality latex house paint, even over latex primer, works pretty well on boats. I include a propane heater, but not a cookstove, as the latter is common enough camping gear. I just listed an overall food and beverage fund. This amount does not reflect a steak and beer diet, but it is something a minimalist could manage.

Bio:

Doug Taylor, 12/7/05
10015 Yaquina Ave., Bainbridge Island, WA 98001

I am a married 57 year old Boomer government worker. My interest in boats goes back to 1959, when I built a pirogue from plans in “Boy’s Life” magazine. The last boat I built was a 17’ variable geometry proa, in 1975. See <flyingproa.com>. I’ve been thinking about it a lot since then, however.

I started the Westalwn correspondence course long ago, but only got to lesson 12. That’s how come I could use Simpson’s Rule to figure displacement. I was a submarine mechanic for 12 years; that sounds pretty salty. I would like to build this design, sometime soon.

Shackles