Max rpm 2800

prowlersfish · Post by **prowlersfish** » Tue Mar 22, 2011 1:05 pm

Do you have a synchronizer ?If so try disconecting it Its one thing both engines share , I had issues with the one on my F30

rossjo · Post by **rossjo** » Wed Mar 23, 2011 7:18 am

Larry,

Ran your F36 numbers using BoatDiesel's (http://BoatDiesel.com) calculators (only $25/year - great deal).

Summary:

You have enough power (when running well)
Your 20x20 cupped 3-blade is overpropped - recommends 19x17 or 20x16 cupped 3-blade.
Your 1-3/8" prop shafts are good to go up to 627HP with a Safety Factor of 2, so go ahead and order those turbochargers!

Power Required Calculator _________________________________________

Hull ........................ Slow Planing
Weight ................... 16,000 lbs
Water Line Length ... 34 feet
Engines .................. 2
Transmission .......... Straight Drive
Desire Speed .......... 25 knots cruising

Speed
To Achieve a Cruising Speed of 25 kts
Required Power
Total At Props: 444 SAE hp 373 kW
Total At Flywheels: 458 SAE hp 384 kW
At Flywheel per Engine: 229 SAE hp 192 kW
Select Engines(2):
Rating ...... SAE HP Metric HP kW Max Kts*
Pleasure ..... 327 ...... 332 ... 244 .. 30.3
Light ........... 286 ...... 290 ... 214 .. 28.4
Medium ....... 255 ...... 258 ... 190 .. 26.8
Heavy ......... 234 ...... 237 ... 174 .. 25.6

Prop. Calculator _______________________________________________

Hull ........................ Slow Planing
Weight ................... 16,000 lbs
Water Line Length ... 34 feet
Engines .................. 2
Output ................... 280 SAE HP
Maximum RPM ........ 4,200
Crusing RPM ........... 3,000
Transmission Type .. Straight Drive
... Ratio .................. 1.9 : 1
Propellor ................ 3 blades
... Cupped Blade ..... Yes
... Prop Diameter .... 20 inch

MAX PERFORMANCE
Available Power: 543.2 SAE hp ( 405.1 kW) @ 4200 RPM
Max Speed: 24.9 kts
Fuel: 33 US Gall/Hr (typical)
CRUISING PERFORMANCE
Cruising Power: 219 SAE hp ( 163.3 kW) @ 3000 RPM
Cruising Speed: 15.8 kts
Fuel: 13 US Gall/Hr (typical)
RECOMMENDED PROPELLER
Diameter: 19.0 in. Pitch: 16.9 in.
Blades: 3 Cupped: Yes
Transmission Ratio Acceptable
PROPELLER BASED ON INPUT DIAMETER
Diameter: 20.0
Pitch: 15.7
Blades: 3

Prop. Shaft Calculator __________________________________________

Prop. Shaft
Diameter: 1.375in
Material: Aquamet 19
Shaft RPM: 4200 / 1.9:1 = 2210
Safety Factor: 2
Maximum Power: 627 SAE hp. (=467 kW = 635 Metric hp)

prowlersfish · Post by **prowlersfish** » Wed Mar 23, 2011 1:20 pm

If it is 2 to 1 or 1.9 to 1 , it is over proped like Ross's numbers say and I belive I thought so be before

The 1 3/8 shafts will be fine the are used with the 330 hp also and I beleve they Aquamet 19 or beter from the factory

rossjo · Post by **rossjo** » Wed Mar 23, 2011 7:09 pm

I'll plug in the Aquamet 19 and edit the post then. Might be useful to others down the road.

If this was helpful, buy a membership on BoatDiesel.com, just like your monarch, King Paul, did.

Best $25 you'll ever spend (except for some fun at the Velvet Drive club perhaps).

rossjo · Post by **rossjo** » Wed Mar 23, 2011 8:27 pm

Updated it with Aquamet 19 ...

Larry - Your 1-3/8" prop shafts are good to go up to 627HP with a Safety Factor of 2, so go ahead and order those turbochargers!

plansea · Post by **plansea** » Thu Mar 24, 2011 10:05 am

Hey Paul thanx so much for all the input. I do not have a synchronizer, but it is beginning to look like I may have a prop problem.
And of course many thanx to Capt. Ross. Ross spent the better part of a day on my boat, very carefully going over everything i had already gone over forty dozen times. Fortunately (or unfortunately) he came up with the same results. One area is still a real mystery, but it seams that both engines are properly tuned and running really pretty well. I had considered the prop issue many times before but, after reading previous forum posts i gathered that 20x20 was original equipment and that is what several members are using. I asked Ross if Trojan had any history of being water-log, he said not ! The plan Sea appears to sit high and proper in the water. I am going to take the advise offered and get my wheels re-pitched. Keep your fingers crossed and i'll keep you posted. Larry

rossjo · Post by **rossjo** » Thu Mar 24, 2011 10:23 am

Both engines really run smooth - revving to 4,200RPM, and the secondaries kick in (trust me, I was standing over them holding the throttle open!).

We would love to know what engine/tranny/prop combo you other F36 owners with 383 or 400 CI Chryslers are running!

Nice boat Larry - enjoyed helping out. Let me know when Sean gets the props on and we'll go test her out!

Putting on my wet suit later today to check the bottom and install new rudder zincs ... summer is here!

rossjo · Post by **rossjo** » Thu Mar 24, 2011 12:01 pm

Turns out F36 is 16,000 lbs, so I'll re-run the numbers later today ... talked to Larry already.

Anything from anyone else on the F36 engine/trans/prop combo?

rossjo · Post by **rossjo** » Fri Mar 25, 2011 7:05 am

Re-ran the calculations at the correct 16,000 RPM, and edited the results above (changes in Red) ...

Larry - the Prop Calculator:
a) recommends a 19x17 prop.
b) if you repitch the 20, it recommends a 20x16.

I think you have 2 choices. Have Oswald either
1) cut the 20x20's down to 19" diameter and re-pitch to 17
2) or simply repitch them to 20x16

Personally, I'd go with simply repitching to 20x16 and see how that works, that's a 20% decrease in pitch, and should help your 400 Chryslers spin up. They sound great by the way - very smooth.

Anyone else care to share their F36 engine/trans/prop comibinations?

prowlersfish · Post by **prowlersfish** » Fri Mar 25, 2011 1:14 pm

Maybe time to replace 2'" is about the max you what to change pitch and I don't believe in cutting down props . doing ether one one throws them out to far from way they where designed .

rossjo · Post by **rossjo** » Fri Mar 25, 2011 2:15 pm

Yes - your probably right.

Plus Larry would like to have his diver swap them at the same time.

So, he's looking for a set of 19 x 17 x 1-3/8 .

We talked, and he'll get the local prop shop's input on these #'s as well.

Geoff R · Post by **Geoff R** » Fri Mar 25, 2011 6:09 pm

Check the metering rods on the secondarys. sometimes the pistons will stick down and not let the metering rods rise.
I run 20 x 21 s with M400s and am quite pleased with the performance ! You could also have a parasitic load robbing power . stuffing boxes too tight etc.

Good luck you,re gettin lots of great help

http://dl.dropbox.com/u/10877359/1975%2 ... 0Sheet.pdf

prowlersfish · Post by **prowlersfish** » Fri Mar 25, 2011 6:13 pm

What gear Ratio ??

Geoff R · Post by **Geoff R** » Fri Mar 25, 2011 6:22 pm

Velvet is 1 to 1 vee drive is 2 to 1

rossjo · Post by **rossjo** » Sat Mar 26, 2011 8:20 am

Geoff - Larry has 1.9:1 - what are yours ?

The engines are actually running good - and the secondaries open and the engine revs great. Larry can check the metering rods (Edelbrock AFB carbs) - good tip. Revving the secondaries open in Neutral wouldn't tell us if the metering rods were sticking and not providing enough fuel at high speed/load. I suggested to Larry that he just go ahead and rebuild both carbs - only $25/each - and about an hour each. What size jets are used in your AFB?

For the record, the carbs are newer (5 years max?) Edelbrock 1410 AFB 750CFMs Marine carbs.

I did find reasonably prices sets of 19x17, 19x16 & 20x16 props, so Larry may pursue these after we check the carb's secondaries.

thanks for the input guys!

Again, we'd love to hear some other engine/trans/prop combinations and performance on the F36.