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Got my prop wrench (boating post)
Richard Casady wrote:
On Sat, 14 Feb 2009 08:37:50 -0500, wrote: On Sat, 14 Feb 2009 01:53:37 GMT, (Richard Casady) wrote: On Fri, 13 Feb 2009 13:24:49 -0500, wrote: On Fri, 13 Feb 2009 18:17:35 GMT, (Richard Casady) wrote: On Fri, 13 Feb 2009 07:29:13 -0800 (PST), wrote: On Feb 13, 9:43 am, HK wrote: Richard Casady wrote: On Thu, 12 Feb 2009 20:46:13 -0500, D K wrote: The one thing I know for sure is the F90 is best suited for a three-blade prop rather than a four. Three is always more efficient than four. Four blades is a way to get the blade area in a smaller diameter, if you lack space. Casady My admittedly limited experience with Yamaha taught me that the company is pretty damned good matching up engines, props and boats, and that a good dealer is also a valuable resource in prop selection. When I took delivery of my 2008 model boat, the boat factory had just changed the prop it spec'd for the boat and engine combo, upon a suggestion from Yamaha. The factory sent me copies of performance print-outs for several props. I was able to almost exactly duplicate the performance on the factory print-out. Almost every outboard boat I considered has performance sheets available from the engine manufacturer, and those sheets specify props. Really? How did they know your exact requirements as far as weight, loading fore and aft, etc.? They give you one in the middle of the range of props that are individually ideal for one of the varying conditions. My sprint car has a quick change rear axle. You can change the gear ratio in a couple of minutes. There are three brands around, and they all have a magnesium case. Stuff is brittle, but there are no impact loads. They have variable pitch props for ships and planes. Variable pitch props and adjustable pitch props are two different things. What does that have to do with anything? You ever see a stern drive trailer boat? You can change props in five minutes. It's only trouble when they have been on the motor for forty years, like the neighbors at the lake. The guy to the east has a pull start 100 hp Merc. He's big, a auto mechanic, and he pulls it easy. One of those inline six "tower of power" motors. They ones to the West has a plywood homebuilt with a 35 hp Johnston, that dates to when that was the biggest motor. Merc came out with a forty and the hp race was on. The auto makers were having a hp race at that time. The fifties when everything had to be bigger and better. I remember when about one boat in fifty had a battery. Three inboards, one of which was the cop, on the biggest lake in Iowa. Most motors were 5 1/2, 6, or 7 1/2. I remember when all the outboards were too small to pull a skier well. The biggest was a 25, and Kirk weighed 200. All the fifties and sixties boats and motors are still around. Motors don't wear out 14 weekends a year. You can fish all day every day and run the motor less than 3 hours a week. I may put two good sized trolling motors on my boat, with two tillers and a tie bar like sailing scows, and never run the engine at all. 5 mph is a good speed for a cocktail cruise. Charge a couple of golf cart batteries at the dock. They make a 2 hp electric outboard, 48 volt, for three grand. Electric outboards start a 135 bucks. Must be something suitable. One hp is about 60 amps at 12 volts. Adjustable is passe for planes. Quite a few ships and most planes have props not only variable, but governed to a constant RPM On an trailered outboard or sterndrive changing pitch with a wrench in a couple of minutes is all you need. That's all it takes to change a prop. Maybe ten if you have help. Someone came out with a two speed gearbox for inboards. Have your holeshot and top end both. Casady What does THAT have to do with anything? Al I did was point out that when talking about props, "variable" does not mean "adjustable". Many people don't seem to understand that. You have a cite for that? The actual uses don't seem to agree. They call them all "constant speed', which they are. All the ones on ships and planes are constant speed. that is governed to a certain speed, regardless of load. [ within limits] All, thats all the ones in use are that way. None are set the pitch and leave it, thats none.All the ones on boats are set it and forget it, with a wrench., out of the water. And they are almost nonexistant. You are attempting to make a distinction that does not really exist, since there are no choices to be made. Casady AutoProp. Also a few years ago, there was some editorial material about a prop whose pitch could be varied while underway. The prop was at the business end of an outdrive. I don't recall whether this was a product under development or just someone's interesting wet dream. |
Got my prop wrench (boating post)
On Sat, 14 Feb 2009 06:57:45 -0500, HK wrote:
Richard Casady wrote: On Fri, 13 Feb 2009 21:35:37 -0500, HK wrote: My first parker was a 25-footer with a flush toilet in the forward part of the pilothouse. In Iowa you would have to put in on a trailer, with a wide load permit, and haul it to a truck stop to get it pumped out. There could be a real temptation there... Casady Yet another reason not to live in Iowa... :) Iowa is a nice place, and it does have the Mississippi, so you can start a cruise to anywhere from here. It just lacks large boats and places to use them. The water skiing as as good as anywhere. All the docks have to be taken out each fall, They used to be post and planks and it was tedious. Casady |
Got my prop wrench (boating post)
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Got my prop wrench (boating post)
Richard Casady wrote:
On Sat, 14 Feb 2009 06:57:45 -0500, HK wrote: Richard Casady wrote: On Fri, 13 Feb 2009 21:35:37 -0500, HK wrote: My first parker was a 25-footer with a flush toilet in the forward part of the pilothouse. In Iowa you would have to put in on a trailer, with a wide load permit, and haul it to a truck stop to get it pumped out. There could be a real temptation there... Casady Yet another reason not to live in Iowa... :) Iowa is a nice place, and it does have the Mississippi, so you can start a cruise to anywhere from here. It just lacks large boats and places to use them. The water skiing as as good as anywhere. All the docks have to be taken out each fall, They used to be post and planks and it was tedious. Casady Psst. I've been to Iowa. Probably a dozen times. You are right, it is a nice place. But I wouldn't want to live there. Too far from salt water. I'd probably like boating on the Mississippi River, though. |
Got my prop wrench (boating post)
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Got my prop wrench (boating post)
On Sat, 14 Feb 2009 09:32:40 -0500, HK wrote:
Now, got any photos of your daughter winning a spelling bee, being named valedictorian, preparing and serving meals to the homeless or bringing cheer to the shut-in residents of a nursing home? Running around a school playing pacman probably won't impress a college admissions board. I want pictures of here riding a bilge board on a scow, on her way to the club championship, like my sister. Casady |
Got my prop wrench (boating post)
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Got my prop wrench (boating post)
On Sat, 14 Feb 2009 09:48:14 -0500, HK wrote:
Also a few years ago, there was some editorial material about a prop whose pitch could be varied while underway. The prop was at the business end of an outdrive. I don't recall whether this was a product under development or just someone's interesting wet dream. Look at the size of the prop spinner on even a small airplane. Lots of room for a bulky hydraulic prop [they usethe engine oil for power] and no pair of right angles in the shafting. Boating reported the flexible plastic prop, but the CP prop for a sterndrive is less than vaporware, at least I never heard of it and neither has Boating. If you put a 3 speed automatic trans on a boat you could have a more powerful engine, as there would be less need for a fat torque curve, as well as staying closer to the most efficient RPM, usually as low as possible. Over thirty foot boats that have trouble getting on plane is the obvious application. With a multispeed trans you could run a sprint car motor, and I happen to have one lying around. About 100 gph of alcohol, in a small block. Casady |
Got my prop wrench (boating post)
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