HANA HOU

[Flying Jack]

:?: Well with such kind and quick response to the last set.
Those who had diesels in th 160 -170 range.
What was the most favorable transmission ,ratio?
Prop blades,size and pitch?
Cruise speed rpm?
Max speed Rpm?
The puzzler Out of the three B 31 In our local yard my 1962 Sport fish hull I.D.#252
has the odd hull my strakes are higher and chines are three feet longer
and i have a small belly from the stern about four feet long ?
I have many ideas to the why but no fact.
Ongoing Thanks
David Freedman

[RussP]

David, we have Brewesters old 6-354 Perkins in our 1963 Sportfish and couldn't be happier. Were running 2 to 1 ZF gears with 20X22 4 blade props. We are a pinch under propped but it works for us as we load heavy for Island and Keys trips. I believe brewester was running 22X24 3 blade props. My next props will be 22X22 4 blade to take full advantage of the HP and recomended by our prop guru. These old Perkins are sort of mystery motors, some specs say 165HP other say 200HP. One old parts guy said it depends if you have the intercooler or not, we have the intercooler. Our cruise is 17 to 18 knotts with a top end of 21 knotts loaded. We burn 14 to 15 gals P/Hr fully loaded at cruise and troll all day on a few gallons. I believe the Styer are high rpm diesels, we top out at 2600RPM this may make a differance in prop size and gear ratio. Hope this helps.

RussP

[Bruce]

The Steyer's are the high rpm, over 4k, and thus what Russ is running will not work.

[Eddy G]

I had 170 Yanmars in my B28 up until last year. 1.5 to 1 Hurth 630a's, 1-1/4" shafts and 18" x 16" three blade Nibral props no cup. I ran them at 2900 rpm at 18 knots. They burned about 10 gals per hour total at that speed with a med load. With proper care and propping I think those 170's will last forever.

Eddy G.

[Pete Fallon]

Dave,
The early 31 hulls do have different bottom strake patterns and more upsweep at the bow chines than the later models. My 1961 express hull # 186 was sitting next to a 1973 fly bridge cruiser in the boat yard in Riveria Beach, Florida. Capt Patrick and I noticed the difference in designs, we measured both boats and they were completely different. Changes were due to mold reworking, after pulling a couple of hundred hulls from the original molds they get tired and have to be redone.
As for low horsepower diesels in a 31 anything less than 200 hp is marginal, the early 1960's hulls are heavy weights compared to later models. I've found that 240-250 hp engines will cruise in the mid twentys and top end around 28 mph, 300-330 hp top end speed in the low 30's. The faster the speeds anything above 39 mph the boats are out running their bottoms and can become hard to handle. My boat (14,000lbs) with 310 hp gas engines, 1:5:1 8 degree down angle trannys, 17x18 3 blade props and low profile struts tops of at 41.8 mph and can be dangerous if you don't watch what your doing.

[Face]

This is all very interesting to me. I am in the middle of a B28 restoration with 2 existing cummins 4bt's (150 h.p.). I have no exisiting performance data as the boat was neglected and the previous owner had passed away. I have tried to find other b28's with these motors, very difficult. There was one on ebay about a year ago. I asked for prop and gear details and never heard from them. I have asked on this site as well. I think most people don't have the heart to tell me the performance will suck! My best educated guess is that I will be able to cruise at 18 knots. I hope so anyway and will let all know this summer when she finally splashes.

Progress: stripped all wiring in the boat, degreased the entire bilge a dozen times, painted the bilge, prepped and painted the entire hull, refreshed motors with rebuilt starters, alternators, turbos and transmissions, new flybridge windshield, new pulpit

I have most everything I need to put the boat back together and am working on it little by little. I have pictures of every step.


Does anyone know anything about my boat? "Weedline" Georgetown, S.C. She will now live on the Chesapeake, Bay, near Solomons Island.
-Joe

[Face]

One more thing, what specifically does a light cup do to performance on a prop? For that matter, what does a cup do to a prop in general? With my low power situation, what are the advantages and disadvantages of a 3 blade vs a 4 blade?

Hopefully these motors will suffice for the next few years as I am a full-time grad student.

[In Memory Walter K]

Mine is an older (heavy) B-31 Sportsfisherman with 6BT 210's with 1 1/2:1 Twin Discs, 1 3/8" shafts and 20X20 cupped Nibrals. I cruise @ 21.5 kts @ 2400 rpm getting me 1 1/2 gpm. Dont know if this helps either of you. I didn't know there was a low HP 4bt Cummins. I did know there was one with 250 hp that had problems with injector tips falling into the cylinders. Cummins made good on those, and "Doc" one of the Faithful, is very happy with his after the fix. Walter

[JohnCranston]

I had mechanical gears made by Kanzaki, 2 to 1 ratio. 1 3/8 shafts, 4 blade 19 by 20 with a medium cup. Engines rated at 3350 rpms wot. We cruised at 2950 at 19-20 knots. wot was 3400 loaded at 22knots. very nice set up for our typical sea conditions here in Texas.

[Face]

Walter, the 250hp cummins is a 4BTA, as opposed to my 150hp 4BT. I have also seen 4BT's on ebay and elsewhere from trucks/equipment rated at 105hp and 130hp. I don't know much more than that. I know many Carolina Classic 28's had the 4BTA's. They have a discussion board with lots of info on the 250hp injector problem.

Does anyone know if I can squeeze some more ponies out of my 4BT's, and keep them together? Probably a better question for the boatdiesel site.

[Kevin]

Sounds like a question for Bruce. My guess is without aftercooler no, but can aftercooler be added to increase power without changing injectors?

[thuddddddd]

Kev, what up dog?? been missing your emails

[In Memory of Vicroy]

Nope, you can't just bolt on stuff and get the hp up, it's a balanced deal that involves the pistons, cam, injector pump volume, etc. The 4BT 150 hp is gonna disappoint you on speed, but if you prop them to turn 2650 rpm with a full load they will run for 50 years at whatever speed they will make, as long as you keep the raw water cooling system real new and keep paint on them, and use a fog of CX on them a couple of times a year. Rust kills more Cummins engines (and for that matter, any engine) than thousands of hours.

UV