The last word on twins versus single screws.
(This letter to the editor was written by Ken Fickett, president of Mirage Manufacturing, to Passagemaker Magazine in response to an article in the August issue on the merits of a single-engine trawler versus a trawler with twin engines. Passagemaker’s response follows, as well as our response to the response.)
C’mon Passagemaker Magazine, you’ve done better
To the editor,
We at Mirage Manufacturing read with interest Bob Lane’s article on single engines versus twins. Guys at the shop have always enjoyed reading Bob’s articles, but as a builder of trawler yachts, we would like to make some friendly criticisms of his latest work.
Bob took great pains to point out that “engine reliability should not be an issue in considering the purchase of a single-engine boat.” In a limited sense, he is right. A well cared for diesel engine in a friendly environment will never quit. Problem is the cruising grounds. They’re always ready to throw up a plastic bag to get sucked up into your intake or offer a pot warp to seize your prop. Wind, current and rocks always seem willing to convert ill fortune into complete disaster.
Robert Beebe, author and owner of the original Passagemaker, had an answer to this reality; if I’m not mistaken, Passagemaker’s two masts carried sails, an excellent secondary propulsion system. Better even than sails is a second engine to get you to safe refuge for repairs.
And speaking of safe refuge, there is a clue to this line of thinking elsewhere in the same issue of the magazine. Tad Roberts, in “Passagemaker Lite,” writes on Page 150, “a large single prop would mean more draft, even with a propeller pocket.” I know Bob is a West Coast guy, so I forgive him, but here in the waters of the North Atlantic and Caribbean, shallow draft can be a tremendous advantage to mariners seeking refuge from weather. Twin engines equals shallower draft equals a greater safety margin.
We agree that the vast majority of trawler vessels are single screw, and we’re not saying folks with single engines are stupid. They show their intelligence by adopting cruising habits to compensate for this handicap the way a deaf person learns to read lips. This truth is evident in yet another article in the same issue of PMM.
In that article, about a nifty harbor in the Dominican Republic, the author laments that trawlers are notably absent. “It’s hard to understand why more trawlermen don’t make this trip. Mom and pop retirees are getting there in sailboats by the scores,” the author writes on Page 136. It’s not so hard to understand, most trawlers are single screws and their owners don’t have the comfort level they need to go through the more isolated Bahamas islands, let alone the D.R.
About half of Bob’s article was about docking advantages of single-screw with bow thruster compared to twin screws. Either works just fine, though naturally as proponents of twin screws, we believe any discussion should be in the wider context noted above.
That having been said, however, we feel using Grand Banks for the test does not do justice to the trawler market as a whole. For example on our vessels, it is actually less expensive to mount two 56 hp Yanmars than it would be to power with a bigger single. That’s because engine and power train costs do not rise in proportion to horsepower, rather more so. What’s more, one of our engines is price competitive with a bow thruster installation, even at the stated cost of $8,000, which we feel is unrealistically low.
I will admit one thing: Thus far in the debate over twin versus single, and deep versus shallow, the deep draft, single-screw faction has prevailed not on the merits, but in the marketing. We hope to change this in the near future. I would invite Bob Lane and the PMM crew to take a ride with us sometime so we can take this debate to the beer-drinking level.
-Ken Fickett, president, Mirage Manufacturing
Ken, you also have some valid points, although we need some clarification on a couple of them. Beebe’s boat was an absolute dog under sails, so sails were never used for propulsion, stability or much else. They didn’t work. Period.
Twin engine installations are far more prone to suck up a garbage bag or ensnare a pot warp than a single tucked into a protective keel aperture.
Your depth issue is accurate and why some boats have twins for no other reason than to reduce draft for gunkholing.
As for confidence-inspiring performance to reach far away places, I have but one further comment on your assumption that owners are afraid to venture far because of issues with their propulsion. Ninety percent of all engine failures are fuel related. Sediment in the tank, or water/dirt emulsified diesel will kill both engines as surely as a single. The thinking that simply having twins ensures some degree of insurance is a fault line I would not care to straddle-the same goes for get-home systems.
Docking considerations aside, a well cared for diesel engine (or pair of engines), with well cared for fuel system and cooling circuit, is the best insurance one can buy.-BillP
Mirage’s response to the response.
We’ll take Passagemaker’s arguments points by point:
(1) Beebe’s boat was a dog under sail. Agreed, but despite Passagemaker’s assertion and Beebe’s own musings, that dog could hunt. We at Mirage Manufacturing have some expertise in this, having built racing sailboats for more than 20 years before getting into the trawler business. Passagemaker, the magazine, is absolutely wrong in saying Passagemaker, the boat, had a sail plan that “wouldn’t work. Period.” Nonsense.
We can see from the photos and plans that Passagemaker, the boat, could sail, even with its stunted rig. Granted it might take 15 knots of wind to get it moving, but that could be said about many motorsailers out there today. As a former sailor himself, the magazine’s editor should know there is a big difference between “sails slowly” and “goes to windward poorly” and “Doesn’t work. Period.”
Moreover, under many conditions, Beebe’s vestigial sail rig would outperform the wing engine that Beebe himself posited as possible alternative. And I say this with all due respect. Beebe, was a pioneer, but he wasn’t infallible.
(2) Lines and garbage bags. While it may be true that unprotected twin screws may have a greater likelihood of fouling, that is not the case with the keel-protected twins favored by contemporary manufacturers such as Mirage and Krogen. As for plastic bags in the intake, there’s no earthly reason twins would be more likely to such them in.
(3) Confidence-inspiring performance. Although you only address this issue in passing, we think you should look into it further. The ICW and other protected waters are loaded with trawlers. They thin out fast even in the adjacent and benign waters of the Bahamas, and by the time, you get to the Caribbean, trawlers hardly exist at all, yet the place is crawling with sailboats. What’s going on here, Passagemaker? If this is not about lack of confidence, what is it?
We’ve done our part. We just took a Great Harbour N37 across 870 nautical miles of the North Atlantic Ocean to Bermuda, demonstrating that anyone with a twin-screw trawler yacht such as ours could do the same without a problem.
(4) Ninety percent of all engine failures are fuel related. We don’t know how anyone can know that with such percentage-point precision, but, for the sake of argument, let’s say it’s generally true. In the real world, however, it will be less true in some places than in others. With the benefit of decades of cruising experience here at our shop, we can say with some authority, for example, that if you do any cruising in Maine, you will get a line wrapped in your prop sooner or later. (And the water there is cold enough to induce cardiac arrest, so forget jumping over the side with a knife in your teeth.)
That’s one of the reasons that we design our trawlers with protective skegs for both props. That, combined, with a broad, shallow-entry stern tends to keep lines away from the wheels. But the main point is this: With twins, you are unlikely to foul both props simultaneously, and even when one is fouled, the other can get you back to the harbor.
Moreover, having a problem with fuel or filters is no guarantee that both engines will fail at the same time. In fact, it is a rare occurrence. To be sure, bad fuel makes it likely that the second engine will go down, but it could take hours or even days. That interval is usually enough time to correct the problem.
-Ken Fickett, president, Mirage Manufacturing