The Artful Dodger
One of the first substantial investments a new boat owner often makes is the purchase of a canvas bimini top and a dodger (aka spray hood) . Unless you have purchased a pilot house vessel or are a round-the-buoys-racer, you will want the weather protection that canvas provides. After seven years of keeping Mandalay in hot and sunny cruising grounds, it is time to replace some of our original canvas. So we are re-evaluating the features so our next dodger and bimini provide better performance and a longer life. Our original dodger was supplied by the boat manufacturer which insured that the design was proven and fitted well. Every canvas shop will have experience with what works and is cost effective. And like so many other pieces of boating equipment, the devil is in the details. So here are some lessons learned aboard Mandalay that might help make good decisions when you purchase or create your next canvas item.
Canvas is in fact a misnomer since it implies cotton canvas from the days of old. Modern canvas is an acrylic material, with Sunbrella being the best known brand. A second alternative to consider is a vinyl coated material that is impervious to water but can become brittle and crack. Acrylic canvas is available in 46" and 60" widths. Dark colors provide better shade from the sun but transmit more heat to the cockpit rather than reflecting it. Expect to pay $12 - $14 per yard for 46" if you buy the raw material from a volume supplier. Th edges should be finished with binding made of canvas, stamoid vinyl or leather. Leather provides rugged protection at wear points.
Windows are made from clear vinyl which is available in 54" widths and various gauges, 40 gauge being the best for a rugged dodger. Vinyl runs about $17 per yard and is quite heavy.......it took two of us to carry a fourteen yard roll.
Our seven year old canvas was made with two different types of thread.....Dabond polyester thread V-69 or V-138, depending on thickness, and thread that was previously known as Gore-Tex and is now called Tenara M1000. Our Tenara thread has never failed in use and would probably last for several more years. The downside to using Tenara is that it is expensive and is so tough that removing it to replace worn out zippers is an ordeal. A seam ripper will not make a dent in it. V-69 has also done a fine job but has required some re-stitching in some areas. If your sewing is perfect, a contrasting color looks nice, but the rest of us should choose a thread color that blends in with the canvas.
We recommend all-plastic zippers which are impervious to corrosion. Some of our original zipper pulls were made of painted aluminum and they corroded away. Unfortunately, plastic zippers will suffer from sun damage and will not last as long as the canvas. Many cruisers have found that black zippers outlast white ones in the hot sun. Our limited experience bears this out. Black replacements we have installed have never failed. A good design feature is the addition of a flap to cover zippers that are in the direct sun.
Turnbuttons, snaps, and lift-the-dot fasteners work well and last much longer than zippers. Buy them from a bulk supplier and they are quite inexpensive. If you can substitute turnbuttons for zippers in your design, it will be more trouble free in the long run.
The framework for dodgers and biminis is usually made from stainless steel tubing of 7/8" or 1" diameter and should last the life of the boat. Aluminum framing is also available but is not as rugged nor as aesthetically pleasing. A large variety of fittings is available to solve most installation problems. We recommend stainless tubing of 1" diameter with stainless steel fittings and fasteners including any pop rivets used with it. Aluminum pop rivets will corrode when used with stainless steel in a corrosive environment. We have through-bolted some of our highly stressed end fittings rather than depending on the set screws supplied with the fittings. Drilling through the fitting and tube is not difficult if you use the set screw hole as a pilot. Building a frame from scratch is best left to a canvas shop unless you have the tools and experience.
A dodger is an invaluable piece of gear. A dodger will shelter you from wind, rain and spray, will allow you to leave your companionway open for ventilation, will provide hand holds, and will even provide some privacy. When designing your dodger, try to eliminate blind spots that cause problems when moving through a crowded waterway or anchorage. If there is clearance under the boom, design the top of the dodger so you can easily look under it when you are at the helm - you will not want to squat down to see where you are going. Insure that there is a tight connection between the dodger and the deck to prevent green water from sliding under the dodger into the companionway. We added grabrails to the side of our dodger to provide a secure handhold for going forward. We also adjusted the existing frame to make our new dodger taller with larger windows and better visibility. The opening window can be pulled back under the dodger and held in place with snaps instead of being rolled up and left hanging right at eye level! Note that dodger windows should not rest against stainless steel framing in the hot sun......use clip on protectors to keep the windows from overheating and discoloring. Center cockpit boats sometimes have a window added to the front of the bimini to function as a dodger.
For those of us cursed with sun sensitive skin, a bimini top is essential. For that reason, we specified that our bimini be as long and as wide as possible. To obtain maximum width, the canvas shop (at Cedar Mills Marina in Texas) mounted the frame on top of the stern rail and after seven years, we are very pleased with that location. To obtain maximum shade for the helmsman, the bimini extends aft beyond the backstay, with a slot in the canvas for the backstay to pass through. That has also been a boon for us and provides shade when we sit on our sternrail seats. Our bimini originally had a window for checking sail trim but it soon clouded up and we eventually abandoned it.
Some sailors opt for a small bimini just big enough to keep the sun off the helmsman. Others stretch a “shade” from their radar arch to their dodger instead of building an independent bimini.
To us, the “shade” is a piece of canvas that transitions between the forward edge of the bimini and the aft edge of the dodger, providing additional shading from the sun as well as almost complete rain protection in the cockpit. Our shade is easily erected using turnbuttons and remains in place most of the time. Our new bimini will have the shade permanently attached with the provision to roll it up out of the way.
Sewing Your Own Canvas
Many sailors enjoy sewing their own canvas. A sturdy machine is required, preferably with a walking foot. Test your machine to see if it can punch through six layers of Sunbrella. We began with simple projects like the “shade” and have worked up to replacing our dodger which was very time consuming and challenging.
After a couple of years, acrylic canvas gradually becomes less waterproof. At this point, application of a waterproofing agent becomes necessary about twice a year. We prefer the paint-on liquid (available from Starbrite and others) having had little success with spray cans.
Zipper replacement will likely be required when a dodger is three to four years old. Zippers are inexpensive but the labor to install them is not. We installed our own with a household sewing machine. Some re-stitching may be needed as the canvas approaches five years of age. A trip to the canvas shop is probably a good investment unless you are equipped with a heavy duty machine and sewing skills. As with maintenance on most possessions, delaying the repairs will usually cause more damage to be done, ultimately requiring much more work and expense.
Well designed and executed canvas aboard your boat will greatly enhance your boating experience, can extend your sailing season, and will improve the aesthetics of your boat. Although we regard the dodger and bimini as essential, other nice additions are weather cloths, side curtains, awnings, and even a full enclosure. Take the time to plan your installation and choose your features carefully to maximize your satisfaction with what is a major and labor intensive investment.
for canvas and supplies:
Bluewater Sailing Supply
866-700-7245 or 727-323-6800
800-348-2769 or 260-693-2242