How to install an inboard motor in a sailing dinghy for sailing dinghy cruising. I cover the pros and cons of an old versus a new inboard installation. There are plenty more articles and video links dinghy cruising and dinghy sailing on my youtube channel, Sailing Moonlight on Youtube This article is a follow-up on the earlier one I did on inboards which talked more about "why" install an inboard motor.
When I first built Moonlight, I installed a original Wing air-cooled inboard. These motors were built after the war using recycled aluminium from scrapped aircraft. It had a nice sound to it, but in the end I replaced it with a modern Honda for 2 reasons. The first was safety and reliability. The magnetos get weak, and the slightest drop of salt water would make it cut out, often at important moments! The second reason was that it sprayed oil into the boat. I had it rebuilt, but it still did it, then I discovered in the manual, "lubrication, splash fed and thorough". I was told by a master boat builder, they did it from new.
It is sure to stir up some controversy, with some preferring rowing with oars, over power. Should you install an old or new inboard in a small classic cruising sailboat, or are oars a better way to go? What do you think? I am interested in your thoughts about the pro's and con's of old vs. new inboard engines. So feel free to make your comments in this video, or on my facebook page. https://www.facebook.com/christopherjsly You can message me personally on youtube itself or on the facebook page. First make sure your sailboat is suitable for installing an inboard. Normally you need a deeper keel with sufficient room to bore the propeller shaft hole. It could be done with a drop-down bracket carrying the shaft on a thrust bearing, but that's not ideal, as it is vulnerable to damage. Next choose your motor. If you are into heritage motors, the Wing website has a register of current owners. There are still quite a few Wings and Pilots about if you have the time and patience to find one. Wing engines are air cooled, but the water-cooled varieties usually have rust issues in the water jackets. The water cooled ones are very heavy and not suited to a small sailboat. There is an interesting history of the Wing engines here, and I believe they have a register of owners, of which I am one. http://www.oldengine.org/members/kenn... The engine mount is usually on timber bearers. There is an art to the "vertical scribe" needed to install the transverse members. A good fit is required, to get the strength and ability to take the thrust and the vibration. The two surfaces need to mate together perfectly, and we achieved that by and accurate vertical scribe, and patience checking the fit by putting paint on one surface, pressing them together and identifying and removing the high spots. Finally after you have done the best you can with that, use a gap filling adhesive such as Araldite. The propeller shaft hole is a technical challenge for the novice. My mentor helped me with that part of the job. and taught me how to make the engine mount. He marked the inside where he wanted it to come out, lined up the long boring bit to drill the pilot hole and it came out exactly on the X. The skills of a master boat builder should be respected. So, there are many different opinions for installing an Inboard motor or engine in a sailing boat. Old vs. New. Having an inboard motor can increase the versatility of a cruising dinghy. Your wooden boat building skills may benefit from knowing a bit more about how to install an inboard. Some people prefer steam engines, I am thinking of electric motors in the future, and the purists would like to stick with dinghy sailing and rowing with oars. Each to his own opinion, but I do a lot of nautical miles in a small boat across some fairly open waters. I like the idea of getting home safely in a squall, and strong currents make rowing impractical on the Great Sandy Strait near Fraser Island.
My installation is a simple direct drive with a deep race thrust bearing to take the load of the motor. It keeps the weight down, and there are less things to break down. In a small boat, not having neutral or reverse is easy to cope with. You soon get used to handle the boat. After all, under sail there is no reverse either, and we manage that OK. In larger craft, a dog clutch is an option.
The inboard motor can be removed easily for pure dinghy sailing. This is achieved by the use of 2 wingnuts to attach the cradle mount, and the universal flexi rubber coupling is disengaged with a twist. For dinghy cruising mode, the re-installation is just as fast, taking no more than a minute or two. Honda have not changed the design of their GX160 in 35 years. They got it right first time! So you can still get one off the shelf perfect for the job. The first one failed from some electrical corrosion, a couple of years after being immersed during a capsize on the St Helens Bar. I had removed the de-compressor cam off the timing gear. That allowed me to slow it down a bit, but it had cooling issues at such low revs. The current Honda inboard motor has looked after us for 25 years now. It still starts first time most of the time. The only part I ever replaced is the spark plug. One spark plug in 25 years and the odd oil change ! I'm happy with that. There is a link to the exact Honda model that has proven reliable and effective for me for nearly 4 decades at the bottom of this page.
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