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Old 15-11-2009, 20:02   #16
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Brett,

The owner's manual contains a detailed reefing table that calls for the first reef in both main and jib at 18 knots apparent when the wind is forward of the beam and 15 knots apparent wind aft of the beam. I don't remember the rest of the numbers and am not on the boat at the moment. I'll return there on 1 December. If you still need to know more details after that, send me a PM as a reminder. I'll be busy preparing for the cruising season and may not look at this thread often during December.
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Old 18-11-2009, 17:57   #17
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Those windspeeds seem early for me to reef but I guess reflect the manufacturer's conservatism.

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Old 01-12-2009, 17:02   #18
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Anyone had a propellor fall off? We lost our port propeller in Costa Rica and had to limp all the way to Panama to get and install a new one. Anchoring is tricky with only one propeller and mooring to a dock or getting underway with only one is also a bit tricky, especially with a cross wind. This is also discussed at length in thread Prop Fell OFF! Help (Prop Fell Off! Help!)
I must have lost more props than anyone (I think 4 in 6 years)! Belize hull #91. But I finally have a solution. Sea Hawk (from down under) makes a locking nut system for the Yanmar SD20. It includes a castle nut and the center bolt has holes in it. Sea Hawk includes safety wire to fix the castle nut to the center bolt, I modified mine to use 3/16" cotter pins. Haven't lost a prop for 3+ years. I got mine from Frank & Jimmie's Prop Shop in Ft. Lauderdale, Florida. (Reminds me, I should order a spare!).

I tried to analyze what is happening wrt to the props falling off. Since the Belize won't handle folding props (not enough clearance between the SD and rudder, shame on you FP!), and Yanmar wants the props free-wheeling when sailing, I believe there is enough vibration with the props spinning to loosen up the prop nut and center bolt. I use the 2 blade aluminum manufactured by Radice - 16 x 12 (sold by Volvo), and I believe they produce some amount of vibration.

Good Luck!
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Old 01-12-2009, 19:19   #19
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Why does Yanmar require "freewheeling"?

I know this is a debate that is as old as the hills but my Volvo guy is quite happy for props to be locked in reverse when sailing.
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Old 02-12-2009, 13:40   #20
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Why does Yanmar require "freewheeling"?

I know this is a debate that is as old as the hills but my Volvo guy is quite happy for props to be locked in reverse when sailing.

The Yanmar distributor states that locking the props in gear while sailing puts undue stress on the dog clutch.

I can't imagine it puts anymore stress than motoring a cruise speed, but then I've never analyzed what a dog clutch consists of.....
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Old 02-12-2009, 14:19   #21
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Hi DtM,
I have never seen any written statement from Yanmar that freewheeling is required!
I have sailed both monos and my current Belize with the saidrive locked in reverse and never had any problems with that. No overhauls or repairs ever required.

Another experience is that a locked propeller has far less resistance than a freewheeling propeller! A simple test is to take one of this small plastic propellers on a stick that kids play with and do this; hold the stick over your head and wack hard forward with the propeller rotating freely. Then tape the propeller so it doesn't rotate and do tha same this again and feel the difference in speed the stick comes forward!

Just a few months ago we where motorsailing to get in time for a party at my brother in law. The wind was at approx 7-8 m/s on a tight reach and we where running both engines at approx 2000 revs and full main and genoa doing between 7,5 to 8,5 knots. I told the first mate to shut down the engines and back the saildrive - and the speed increased to steady 8,5 and above! So even apropeller on a running engine is actually breaking more than a locked propeller when under sail doing good speed.

So, my advise is to lock the prop as soon as you can. And from the point of damage to the saildrive - never freewheel as this create more stress on the bearings and also more wear to the gear teeth.

Happy lead free sailin
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Old 02-12-2009, 17:09   #22
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I certainly would rather lock the props. Two things I don't like about spinning props....they're noisy (you can hear the shaft(s) spinning when you are down below) and they're more susceptible to picking up lines in the water. I live where crab pots are planted from October 15 to May 15, and it's not fun to clear a fouled prop in 4-6 footers.

I'm curious why reverse? If I remember correctly, the gear ratio on the SD20 is the same in forward or reverse.
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Old 08-12-2009, 04:19   #23
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Quote:
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I'm curious why reverse? If I remember correctly, the gear ratio on the SD20 is the same in forward or reverse.
if it is, then its the same, but locking is the best.
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Old 08-12-2009, 07:23   #24
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Locking the gear in forward (while going forward) is like parking your car facing down a hill and leaving it in first gear. The turning force will act on the whole gear train and try to turn the engine over. Putting it in reverse locks the gears against the turning force (unless you are sailing in reverse!).

I am pretty sure the gear ratio is not the same in forward/reverse on the Yanmar SD20. I know they are the same on the Volvo 120SD.

Volvo recommends putting the saildrive transmission in reverse when not using the engines.

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Old 08-12-2009, 13:47   #25
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Locking the props

To lock up in reverse is anbsolutely correct the car analogy is quite correct.
The Yanmar SD20 seildrive ratio is 1:2,64 both forward and reverse.

Happy lead free sailin
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Old 09-12-2009, 09:33   #26
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Locking the gear in forward (while going forward) is like parking your car facing down a hill and leaving it in first gear. The turning force will act on the whole gear train and try to turn the engine over. Putting it in reverse locks the gears against the turning force (unless you are sailing in reverse!).

I am pretty sure the gear ratio is not the same in forward/reverse on the Yanmar SD20. I know they are the same on the Volvo 120SD.

Volvo recommends putting the saildrive transmission in reverse when not using the engines.

Mark
I agree with the scenario of parking your car. But I disagree that is analogous to the SD20 saildrive. The SD20 is a different design than a car transmission. I pulled the service manual/parts list and studied the SD20.

1) The SD20 is the same gear ratio forward and reverse, as Lucky pointed out.
2) The direction is determined by the dog clutch (#44) meshing with either the top gear assembly. (#36) or the lower gear assembly. (#36).
3) The main drive gear is the same part as the upper and lower gear assembly. (#36).
4) All the lower shafts/gears will see no difference in stress whether one locks the prop in forward or reverse since the direction selection is made at the top of the unit.
5) Since all (3) of the upper gear assembly are identical, there is no more or no less stress placed on any of the upper components when locking the prop in forward compared to reverse.
6) The end result is the locked prop will either try to turn the engine in it's normal rotation or reverse rotation. Since the locked prop doesn't ever have a chance of actually turning the engine (just not enough power there) in either direction, it doesn't matter if you lock the prop in forward or reverse.

After examining this, I do agree that locking the prop has no significant wear on the SD20 (in contrast to what the Yanmar dist. told me). The wearing of the ears on the dog clutch due to the extra shifting in/out of gear is so insignificant over the life of the clutch, I'm not going to worry about it.

I like forward as it keeps the shift levers out of the way so I can play with sheets and winches.
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Old 09-12-2009, 16:06   #27
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A good result from a reasoned discussion.

Good sailing

daniel
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Old 10-12-2009, 11:13   #28
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I'm with DotDun in spite of the owner's manual specifically stating that the saildrives should be left in neutral while sailing. In the long run, the insignificant wear on the gears caused by locking has to be way less than the wear that would be caused by letting them spin.
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Old 11-12-2009, 07:37   #29
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Quote:
Originally Posted by Dreaming Yachtsman View Post
I'm with DotDun in spite of the owner's manual specifically stating that the saildrives should be left in neutral while sailing. In the long run, the insignificant wear on the gears caused by locking has to be way less than the wear that would be caused by letting them spin.
Well its your money,
i would never let them spinn. it would cost me to much,
i lock them
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Old 22-12-2009, 12:40   #30
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Year end

Hello all Belize owners and other readers and contributors on the threa.

Lucky is now on the hard for some TLC for the next season. Will add a hard bimini and possibly a new chartplotter. Also the plan is to change the genoa sheet over to the starboard side.

I would take the opportunity to wish you all:

Merry Christmas and a Happy New Sailing Year from Lucky

Looking forward to continue the thread in the new year.

Happy lead free sailin
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