Prairie 29 engines

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Al,
I worked at Washington Iron Works. They had long since stopped making the Washington Diesel engine but I went through a lot of old drawings of the engines. Three cyl to 10 cyls were there. All made there on 4th ave so in Seattle. That was in 1959 .. just before I went to work in the gold mines in western Alaska near Bethel.
 
And 0' Golly! The sounds of those stamp mills in the fleet of halibut schooners that traversed the channel coming one after another in a solid continued line like a string of snow geese before the season started,into Ketchikan A young boy would listen to the "Pukka, pukka, pukatchuck, each engine made and at a different cadence according to those number of cylinders employed. Good days and good sounds. There are a couple of the old schooners (Tugs too) still powered suchlike . You were fortunate to have worked and I suspect too had listened to the solid "Curchuncks" :dance:
Here you go:

 
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We launched Sue Marie today. She had been on the hard for a month, removed all the bottom paint, put back four coats of barrier protection two coats of petit Bottom paint. Also switched props. Had a 18/12/3 blade prop, replaced with a 18/13/4 blade.

Had a smooth but rainy day for our 17 mile ride back to our home port. an smooth, and quiet. Too her up to 2600 , louder , reached 6.8 . Put prop speed on the prop, used this product in the past on a twin engine sport fisherman. In these warm waters it works great. :)

Wanted to do this project three years ago, with my wife's illness had no time. Glad I got it done.

John
 
Sortie said:
We launched Sue Marie today. She had been on the hard for a month, removed all the bottom paint, put back four coats of barrier protection two coats of petit Bottom paint. Also switched props. Had a 18/12/3 blade prop, replaced with a 18/13/4 blade.

Had a smooth but rainy day for our 17 mile ride back to our home port. an smooth, and quiet. Too her up to 2600 , louder , reached 6.8 . Put prop speed on the prop, used this product in the past on a twin engine sport fisherman. In these warm waters it works great. :)

Wanted to do this project three years ago, with my wife's illness had no time. Glad I got it done.


So in the end, you did go for the bigger wheel. You indicate 2600 RPM.What now during a short effort, is your WOT? I recall you mentioning 4000 RPM by engine data was WOT, then again, I want to recall without reviewing the thread, that contrary, your top WOT was less. That being with the smaller wheel. Within prior conversations shared by Manyboats (Eric) addressing the need to reach engine manufactures RPM as wheel selections are anticipated, it would appear that you have made a satisfying choice on the wheel. Eric is correct in his prognostications and the unknowing or inexperienced should heed the manufactures recommendations. Some challenge in the spirit of 'Tweaking' the recommendations to optimize a specific desired outcome.
Glad to hear that your effort on 'Tweaking' paid off.
By the way, had you ever had or know of the 4-108 having habituial rear main seal leaking??
Thanks and to the thread and Prairie owners. I count this thread with the amount of good sharing of different points of view as one of the better sites. As the Prairie is close in all sectors with our Marben.

I'd ask to be adopted into the Prairie owners category as our craft source of information and ownership's is skimpy. This category serves as a friendly bunch and source. to bounce off similar subject matter.
Cheers

Al-27' Marben Pocket CRUISER
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Al,
He did say he put on the 4blade. But he didn't say 2600 was WOT.
I don't know for sure but I'd be inclined to consider the 107/108 Perkins a 3000rpm engine. Every engine I've known is 3000 but I've read about the English taxi cabs w 50hp at 4000rpm. The 3600 and 4000 engine rating is a bit of a mystery to me.
 
manyboats said:
Al,
He did say he put on the 4blade. But he didn't say 2600 was WOT.
I don't know for sure but I'd be inclined to consider the 107/108 Perkins a 3000rpm engine. Every engine I've known is 3000 but I've read about the English taxi cabs w 50hp at 4000rpm. The 3600 and 4000 engine rating is a bit of a mystery to me.
Click to expand...

Eric,



Those are "marine ratings" and they come straight from Perkins:
  • 3000 rpm is "Max. continuous rated speed"
  • 3600 rpm is "Max. intermittent speed"
  • 4000 rpm is "Max. speed for approved high speed pleasure craft"
attachment.php
 
Hi Eric,

Quot:
manyboats said:
Al,
He did say he put on the 4blade.

Correct Eric, but the poster indicated a four blade dia and pitch 18X13 indicating that the wheel is larger than the three blade 18X12 he had before.

Normal formula results have a four blade measurements less than the three blade. Here by the numbers given, he has increased the wheel sizing hence the WOT now becomes interesting to see if he is 'right on' or over wheeled.

Al-27' Marben pocket CRUISER
Click to expand...
 
LarryM said:
Eric,



Those are "marine ratings" and they come straight from Perkins:
  • 3000 rpm is "Max. continuous rated speed"
  • 3600 rpm is "Max. intermittent speed"
  • 4000 rpm is "Max. speed for approved high speed pleasure craft"
attachment.php
Click to expand...

Eric, here is a good point to throw around. Our 4-236 corresponding information as I recall was 2500 RPM for Continuous rated speed, 2800 RPM for intermittent speed. When we were cussing and discussion wheel choices during the re-fit the final decision was go with the 2500 RPM rating. We did and of course the results were as reported, we were only able to obtain 2000 RPM WOT. So as you and I have discussed, I am horrendously over wheeled.
Enough to make a knowledgeable prop person to cringe for sure. Actual running has proved that there is no advantage of running the engine more than 1450 RPM to obtain the hull speed which is graceful and pleasant to the soul. Still as stated often, we still have 500 RPM to WOT. And by diesel talk, 3/4 of engine throttle usually equates the best torque range.

Regards.
Al
 
WOT on my boat is now and has always been 3600. According to the original owners notes, he never achieved anything over 3600,nor he really try. I have had the same experience. After 3100 rpm, the engine does not sound happy. The owners Manuel repeats the Perkins numbers for the 4-108.

Al, the 4-154 was known for rear main issues. My goal is to have an efficient and smooth a ride as possible. If I can achieve hull speed at 2500 I am happy.

John

Al, you are a member of the Prairie group.
 
Sortie- Thanks and I will attempt to live up to the extended honor!:flowers::thumb:

Your response to me indicates that WOT is short. Not by much when you consider 3100 vs. 3600. One question. You indicated 'Rough sounding and not happy'. Is that 3100 WOT or is there more throttle and you are reluctant to push it? Second, Eric should consider your information and allow it to align it self with his calculations. It would seem you will not be hurt in either discussion.
Thanks on the confirmation of 4-154 seal issues. I had asked as I had not heard any on either the 107/108 although to my understanding the rear seal assembly is similar or same. I did suggest to the party that purchased our 4-154 to have the rear seal, recently replaced, done again as the recent fix was showing signs of leaking.
We took a 9 hour voyage today. Ran at 1450 and maintained a 6.9 knot average. So quite, we spoke in normal voice. Apple pie and ice cream didn't hurt either!!!
Al-Marben Pocket CRUISER
 
Al, Thanks for the question, gives me an opportunity to correct my poor presentation. Instead of rough, better word is loud, which makes me unhappy. It also makes my companion, Teddy the Beagle, unhappy. I am reluctant to push the engine beyond 3100. It will go to 3600, but I see no reason to do that. After 2600 the gain in speed is not worth the noise. In addition to my preference, it is a 38 year old engine that spent a long period of time with no to very limited usage. Like its present owner it deserve to slow down and not work to hard, thus preventing unnecessary breakage or failure.

I know a couple of fellow Prairie owners who have the 4-236, they are very fond of these engines, as would I.
 
Sortie said:
Al, Thanks for the question, I am reluctant to push the engine beyond 3100. It will go to 3600, but I see no reason to do that. After 2600 the gain in speed is not worth the noise.]

2600 out of a possible 3600 RPM shows a goodly spread. Let me ask, do you have sound barrier on the bottom of your engine (floor?) hatch? Asked as I purchased enough to make three layers of sound insulation matting. I purchased at our local NAPA (Pep Boys, O'railly'). It is use as a heat shield by some, the sound proofing is a bonus. I secured the matting with those nails with the plastic washer thing-a-majiggy. Will take a photo with my phone next day or two and will have to email over this trawler format should you have a problem viewing what I am trying to explain. The end result of this insulation is just unbelievable when you open and then close as your are traveling. If you don't have this and room to apply, consider it.
Thanks for the come back,
Al Marben Pocket CRUISER.
Click to expand...
 
Al, Thanks for the suggestion. I do have sound barrier, it is, however, in bad shape. .
John
 
Al Slip Aweigh has a 4.236. I run her around 2000. We seem to reach warp speed of around 6.3 knots. Fuel consumption is below one gallon per hour.
I have run her up to 2650 a couple times. The most I generally run is 2200. This equates to around 6.8. The increase in noise level is not appreciated by either the Mrs or the hound. So the comfort level is 2K or less. I have found trolling speed is around 1500, 4.25 kts, seems to work best, and engine is whispering.

I'm not in a hurry, unless the Grandkids are getting cranky, and then I have to skedaddle back to port. But, they all know that when on Papa's ride it isn't a fast sportscar, but a comfortable mobile couch with an after swim warm shower, toys, and snacks for the trip. Why the heck do I even go home?

And, at some point a PO installed sounddown insulation under the salon deck and on 'most' of the ER side of the bulkhead to the bow.
 
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3100rpm WOT on a 4-108 is about as good as it gets.
 
cappy208 said:
So the comfort level is 2K or less. I have found trolling speed is around 1500, 4.25 kts, seems to work best, and engine is whispering and, at some point a PO installed sounddown insulation under the salon deck and on 'most' of the ER side of the bulkhead to the bow.
Click to expand...

Neat!! At 1500 RPM in gear, you now have an idea of my sound level at hull speed 6.8-7.1 Knots+.

Trolling speed for King Salmon is best at 2-2.5 knots. At dead throttle stop of 500 RPM we are at 3.5 knots, too fast, so the 9.9 Yamaha OB is employed.

I mentioned using the heat shield/sound deadening matting that comes in a roll from the local auto parts store. What is the material or stock that your boat is deadened with? It may not be cost effective to add any to our craft were it complicated. The gain over what the engine sound is now may be nil.

Al-Marben Pocket CRUISER
 
I have found, (not just on this little craft, but on many others) that it is not just the sound deadening absorptive insulation on the underside of the deck that is key, but the actual mating surfaces of the hatches, and scuttles on the deck plates that allows much of the noise to filter through. As you walk along the deck does the pitch of the sound change? That is from the hatches lifting, flexing and breaking the seal of the deck frame. To me this is a larger part of the sound deadening success.

If you have all the sound barrier in place its effect is dramatically lessened if it 'leaks' from the hatches anyway. Another issue is warped plywood and chipped edges.

I have not looked carefully at the specific insulation on Slip Aweigh to see a brand name. It is two layers of 5/8" black foam with an orange hard plastic (approx 1/16') layer between the two with aluminum foil on the side toward the engine compartment. It is held on with some adheshive. I have used the glue on studs with the snap on covers you mention. They work well with rockwool panels even on the overhead.

On most boats I have worked on in the past 35 years sound deadening is almost universally appreciated. Even if it helps a 'little bit'!

You have a get home kicker. How much speed do you make with the OB? Can the rudder steer even if the OB is behind the rudder? Is the OB on the centerline?
 
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Cappy,
I agree. There's path for engine sound right near my throttle lever ... I don't see it but but the sound comes right up there. And I remember riding on the old Wn State ferries. On some of them the windows would rattle. Dozens or more windows rattling away made quite a racket. Sounded like a bunch of kids hitting the furniture w sticks. Willy also has a rather heavy sounding rattle in the lazerette that I've never found. Must be in the inassesable space behind the port water tank. Bulkheads can "drum" and of course there's dishes .. or that tea kettle on the stove.
 
manyboats said:
Cappy,
I agree. There's path for engine sound right near my throttle lever ... I don't see it but but the sound comes right up there.
Click to expand...

Eric,

I had the same sound until I figured out that it was coming through a tube connecting the engine compartment to the control console that contains wiring and control cables. It was also 'leaking' noise into the pilothouse where the tube passed through the deck. I sealed it there and inserted foam rubber into the upper end of the tube and voila, no more noise . . . OK, less noise :socool:

Cappy,

I totally agree. After installing Soundown insulation throughout the engine compartment, I discovered there was still a tremendous amount of noise coming from around the hatch. I removed it, trued the mating surfaces and installed Taco Hatch Sealing Tape. It worked wonders :thumb:

61BNqdVw86L._SL1500_.jpg
 
LarryM said:
Eric,

I had the same sound until I figured out that it was coming through a tube connecting the engine compartment to the control console that contains wiring and control cables. It was also 'leaking' noise into the pilothouse where the tube passed through the deck. I sealed it there and inserted foam rubber into the upper end of the tube and voila, no more noise . . . OK, less noise :socool:

Cappy,

I totally agree. After installing Soundown insulation throughout the engine compartment, I discovered there was still a tremendous amount of noise coming from around the hatch. I removed it, trued the mating surfaces and installed Taco Hatch Sealing Tape. It worked wonders :thumb:

61BNqdVw86L._SL1500_.jpg
Click to expand...

I, too, have noticed the sound levels vary as I move about the saloon. The sealing tape on my hatches is just about non-existent. I plan to re-seal the hatches. My only other source is the shift/throttle cables transmitting sound up to the lower helm quadrant. I plan to wrap a bit of this seal tape on the exterior of the cables under the helm to muffle this transmission of high pitched noise.

John - Thanks for the valuable info on your wheel replacement.

-Evan :thumb:
 
cappy208 said:
You have a get home kicker. How much speed do you make with the OB? Can the rudder steer even if the OB is behind the rudder? Is the OB on the centerline?
Click to expand...

Cappy- I will PM you with information on OB. Could start thread creep.
Al:whistling:
 
Cappy: You cruise at 2,000 rpm, right? Well, the P.O. of Rise 'n Shine adjusted the propeller so that I get 7 knots at 1400 rpm. The fuel burn makes me think it's making around 25 horsepower at that speed, which is more than a little rediculous for a 185 hp engine.

But, it's bought and paid for, so I'm going to go with it.

Cheers! ...thinking of spring

JS
 
On Rise 'n Shine the main sound reducing factor is the propeller - the P.O. "overpropped" the unit so I cruise at 7 knots at 1,400 rpm. It's making around 25 hp, I reckon from the fuel burn (which is a little ridiculous for a 180+ horsepower engine) but it works well, and is also a significant fuel savings over running the same engine at 1850 or so rpm with a "correct" (i.e. optimized for maximum power) screw.

So, my attitude is to pop a tab and enjoy it!

Cheers!

JS
 
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Driftless,
It ain't ideal but I'd probably do the same w your boat.
I think your "25hp" is very close. My Willard FD takes about 18 as a widely accepted number in the Willard Boat Owners Group (yahoo). My cruise is 2300rpm.
 
@ Driftless:

I do try to keep her at 2K. But if in serious 'get homeitis' mode (crying GrandKids and all) I have run her up to 2700 or so. But, in all honesty, running over 2K is NOISY, and just obnoxious. I'm happy plodding along at 6.5 or so. Autopilot works like a charm, and I only have to watch out for pots, and the errant WAFI coming my way to avoid.
 
Yesterday, as I commissioned Rise 'n Shine for the season, I was averaging 6.2 knots at 1,100 rpm. The coolant temperature leveled out at 150 F. even with the new thermostats. I double checked the temp with an IR heat gun, and the gauge is about right.

The good news is the noise level is very low, and the fuel burn has to be mostly for engine friction rather than moving the boat. Again, it's more than a little overkill, an engine rated for 185 continuous, running at what, around 20 horsepower?

OTOH, it's bought & paid for, so I'll keep 'er going.

Cheers!

JS
 
@driftless: Now that you are all wet, Give me a couple weeks. Have to patch a blister repair I peeled off when stripping bottom last month. Then paint and splash. Have to do a side by side fuel burn check.

By any chance do you know the dia/ pitch of your wheel?
 
Driftless said:
Yesterday, as I commissioned Rise 'n Shine for the season, I was averaging 6.2 knots at 1,100 rpm. The coolant temperature leveled out at 150 F. even with the new thermostats. I double checked the temp with an IR heat gun, and the gauge is about right.

The good news is the noise level is very low, and the fuel burn has to be mostly for engine friction rather than moving the boat. Again, it's more than a little overkill, an engine rated for 185 continuous, running at what, around 20 horsepower?

OTOH, it's bought & paid for, so I'll keep 'er going.

Cheers!

JS
Click to expand...

I wanna know what happens when you push the power up....like 2200 or 2400rpm. Will it plane out???? As a previous P29 owner, I am just curious and always wondered. It is definitely a semi planing hull. And with that much power, that thing should fly!!!
 
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