prop size

[Koinonia]

I just thought Id post some information regarding our props.  I didnt check when the boat was out of the water so I took a peak yeasterday and found my prop to be a 12X9.  The boat is an 86 and has the M12 universal diesel.  Sometime soon, most likely when Im done buffing her out and redoing the teak I will pull the prop and try a couple others I have around the house.  One prop is a folding 12X12 and looks like it will fit nice.  I had this prop on a catalina 27 and it was much better than factory, that boat had the 5411 universal diesel and it turned the prop fine though the boat is a differant design as far as the hull being slippery.   Another prop I have laying around the house as a door stop is a 13X14, this prop Im really curiuos about.  I am on a lake with no current and will take gps speed before I do the swap with no headwind and calm water.  I will do this with each prop out of curiosity and if there is a good wind and chop then well see what effect that has on the boat.
   Im still keeping and eye out for a universal M25 for the boat, or a very well priced kubota d850 or 950 motor.  What Im looking for is better motoring performance dealing with wind and waves, that is when they arent in your favor for sailing and there is a timeframe.  When Im retired Ill have time to be a purist!

[skip1930]

Folding props don't like to go backward very well...but the diesel luv's to work hard. They pull the R's and will add fuel to the air to maintain the throttle setting. All the way up till they start to choke on the added fuel and no longer light the fire. Then the load has to come off until it's all cleaned out and she'll try again to pull the load.

I have a New Holland TS-110 turbo tractor with 21 foot of flail that some times bogs down in thick grass out in 'Indian Terratory' at the aeroport. She chugs and smokes and shakes at almost no rpm's and cleans herself out after a bit of this nonsense and off we go again in a lower gear or with one flail lifted out of the cut.

Put a prop on that she can pull without choking on her fuel load.

I always wondered why an automotive type 'tranmixer' won't work on a boat/ship/yacht.

This is not the tractor but it looks looks this except it's aeroport yellow.

skip

[Allure2sail]

Hi:
The prop on the boat is a 12 x 9. The spare prop I have off of the parts boat (same year & size) is a 12 x 8. Never tried it or could figure out why they are different pitches.
Bruce

[Koinonia]

My father in laws kubota tractor does the same thing if I am bush hoging and pick a few to many young trees at once.  Its also a 3 cylinder that would be great in the boat and I joked to my wife about her dad comeing home to a tractor without an engine.  This is why Ill be trying a couple differant props to see what the outcome is.  Ive had folding props before and their trick is more rpms to keep the blades slung out then once the boat is moving you can back down on the throttle. 
   Interesting on there being pitches, maybe the one boat somehow damaged a prop and a 12X8 was all they could get their hands on at the moment, or like one guy at my sailing club who had his prop stolen, boat was in the water to.  Somebody must have really wanted it!

[skip1930]

A prop with a lot of pitch MIGHT not allow a speed slow enough for certain maneuvers. Maybe I don't know.

On one of the parents five houseboats over the years we had one with twin 383 Chrysler in board out board with 'Velvet drives' between the out drives and the engines. With both Carter four barrels standing wide open with the flame arestor off one could see the fuel pouring down into the manifolds and the DARN ENGINES topped out at no more than 3400 RPM but the boat was on plane. Props were stainless steel and four blades with a lot of pitch. Idling in the harbor was fast.

skip.

[Tim Gardner]

Skip,

You're the best. I love your sense of humor.
tg

[Koinonia]

anybody here with a westerbeke experiment with a 3 blade?

[Allure2sail]

Hi all:
I have an opportunity to purchase an M-!8 which is also a 2 cylinder universal (Kubota Block). These motors are rated at 14 HP which is 4 more horse power than the M-12 which is rated at 10 HP. My question is do you out there think this is worth the time and labor for 4 more HP. I know the later 27's have an 18 HP motor and that setup works out well. So does anybody out there possibly have a 14 HP diesel setup in their 27's and if so did it fix the underpowered situation. In a chop or motoring against the wind and a current this boat goes no where (1 or 2 knots, if I'm flat out). If I do this swap is there anybody who would be interested in buying a good M-12 (includes a complete spare motor for parts)?
Bruce
S/V Allure

[Koinonia]

    Allure,

    I think most people on the board wouldnt go through the effort for the 4 hp gain, and in reality the m12 is rated at 10hp at 3600 rpm so when cruising around 2500 were not making alot of hp, just torque.  Id love to see the torque figures on these engines but that figure is hard to find.  Can you find any other kubota motors around?  Reason for asking is that when looking up part numbers for our engines they all have the same transmision and same 2:1 reduction.  Also water pumps carry the same part number, starters are the same part number, the differance is bell housings have differant part numbers.  With that I havnt checked part numbers on the flywheels.  The other mystery that has my curiosity is the adaptor plates that go between the engine and bell housings.  I will have more answers to this soon since I just got my hands on a low hour kubota D950 motor and am about to get a complete m25xp with everything very cheap which happens to have a trashed motor.  With that I will have about 800 in my fairly fresh M25xp motor for my boat when I put the two together which is rated at 23hp.  The boats design doesnt allow for going to nuts on the prop though, its looking like a 13X12 3 blade prop may be my best bet.  Its also going to be a tight fit length wise in the boat.  I may have to trim a little off the shaft and make my electrical panel area shallower and put a plexiglass protective plate behind it to keep any wires away from the engines belt.
   In this project I will be able to compare engine pieces between the two motors to see if somebody with an M12 could really just get a plain motor and make it all work with the addition of buying a M25 exhaust manifold.
     This does seem like overkill and it is but the M25 and M25XP motors are great engines.  You can carry more spare parts on board without going broke, just compare a fresh water pump on a M25 verse a 3GM yanmar, youll say ouch.  Alot of people also say to go to a kubota tractor dealer for parts, dont! Go though the industrial engine sources like Engine Power Source our of Rock Hill SC.  With these guys go with your engine code and not a tractor model  number.  It goes really well if you already have a parts manual and can give them the part number as well.  The industrial side is cheaper than the agricultural side, which is cheaper than the marine side!  I know about Power Source as I rebuild a Universal 5411 motor a couple years ago for a catalina. 
     I will most likely not post much about whats going on unless somebody ask me directly as when Im dont I can do an organized how to with what did and didnt work with pictures and tech data.
   Im not expecting speed records under power but Id like 6 knots though the water even with some moderate winds and chop which is where the M12 just cant do anything.  In retrospect alot of smaller boats with atomic 4s were overpowered and Ill use my ranger 29 as an example which I used to own.  That boat could motor a comfortable 6.5 knots and I never stressed the engine since I didnt have a tach on the boat.  The sternwave was huge at that speed though!   
   Weight!  With this conversion there is also a weight differance, its only 100lbs increase with the bigger engine so Im not worried.
   Fuel!  This will just have to be found out, the bigger engine doesnt need to rev as high so you can theory all ya want but Im not worried about it, Id like to put a larger or second fuel tank in the boat anyways.

    Wish me luck!

[Allure2sail]

Hi:
Have not done anything with this engine swap idea yet, but still an option. Just wish it was a bigger engine (18 HP) but it isn't. Trying to get the history of the motor (hours, what it came out of and any maintenance records available). On your project I don't think the 100 ponds will affect much but the extra cylinder (that is a three cylinder I believe) thus longer block will make for an adjustment or two. I have purchased whatever parts I can get away with from the local kubota dealership. Good luck with your project. Going to start cutting up the parts boat soon (before winter) so if you need anything just let me know.
Bruce
S/V Allure