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Cruising speed on 1984 28b11 Catalina 281

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richard dragolic

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I have a 1984 Catalina 281 28&

I have a 1984 Catalina 281 28'11" with twin 305ci 230hp engines does anyone know the cruising and top speed on this model? Also what is the cruising RPM on this model?
 
I own a 1985 281 which I just

I own a 1985 281 which I just repowered with 350's. I have 13x11 props. I don't go over 3000rpm because the mechanic told me that is when the secondaries open up. AT 3000rpm I go 18 mph and burn 25 gph. All the catalinas I see for sale advertise that they cruise at 20 mph.I am not pleased with the gas consumption.I have trim tabs
 
"John:

Your boat is WAY und

"John:

Your boat is WAY under propped. I'll bet, if you opened 'em up, the tach would get close to 5,000 rpms! (It's like you're running in low gear.)

I have a similar but different boat, a 32 Marinette with twin 360 Chryslers. The "experts" insist it should top out at 4,400 rpms or more. Phooee! I repropped it to top out at about 3,600 rpms (or a bit more--can't afford to find out!)

Gas mileage and speeds are as follows (and yours should be similar or better):

At 20 mph, 2,500 rpms, I burn 17 gph total. THat equates to 1.2 to 1.25 MPG. There's no reason yours shouldn't do even better, seeing it's a lighter boat.

Jeff"
 
"This is an interesting discus

"This is an interesting discussion and one that many people are trying to deal with. I have a 251 with a single Chevy 350 and it uses 6-7 gph at 3000 rpm. At 3500 rpm about 8-9 gph. The high speed jets do not kick in until around 3700, one can clearly hear it happen and then it uses lots of gas, I imagine. Now my real question is I have a 13 x 11 prop (which many "experts" swear by for this boat) and at 3200 rpm I am only at about 12 kts on the gps after adjusting for currents. Am I underpropped too? It seems if I could get that 12 knots at a lower rpm my engine would be better off. Any expert suggestions appreciated. It seems that I should be able to get into the 20's top speed and to cruise without the high-speed jets open at 16 kts but I am not there yet. Less radical ideas are smoothing the bottom and getting ther tabs working.
Jim"
 
"If this is a "281" &#

"If this is a "281" (you wrote "251") then I would assume it's an underpowered boat that needs to rev at least 4,500 rpms at WOT. John's boat and mine are NOT underpowered. Mine, for example, would LEAP out of the water with the stock props--you better be hanging on, Bub! (I wan't one day and went flying when the "Admiral" nailed it.) After going to 4 bladed, much higher pitched props, the boat is less aggressive out of the hole, but it still gets the job done without strain. Understand?

Jeff"
 
I understand John's is a 2

I understand John's is a 281 with twins and mine is a 251 with single engine. My question to you is if my WOT is 4400 rpm do you consider me to be underpropped? (I think I hear "yes" from you.)
Jim
 
"I'd say you're pretty

"I'd say you're pretty close to correct. The boat might plane off quicker with a bit less pitch, but you'd pay for it in gas mileage.

Jeff"
 
"John:
You have twin 350&#39

"John:
You have twin 350's and your cruising at 18 mph at 3000 rpm's? Something sounds wrong there, I have twin 305's and at 3000 rpm's I'm doing between 28 and 30 mph on the gps.
Rich"
 
"I took my boat out today and

"I took my boat out today and the seas were pretty calm. For the first time in 6 years I opened it up and at 4500 rpm I was going 30 mph. Rich, do you know what kind of props you have?At 3000 rpm I was going 18 mph. The bottom of the boat is clean.JR has the same prop as me and he has a single screw. The prop rebuilder said 13x11 is the correct prop. I do know something is not right, but what is it."
 
"John:
I'm not sure what

"John:
I'm not sure what kind they are we just bought the boat last year, but I have a spare prop that came with boat and there are a few numbers on there that might help you, they are 3217 and R425. I hope this will help. If you or anybody else knows what these numbers are please let me know.
Rich"
 
"Hello, Richard, John, and Jef

"Hello, Richard, John, and Jeff.
I also own an 84 281 with twin 350. At 3000 rpm I do about 20 knots. I just repowerd the boat with these engines. I am actually an automotive tech and have built sevral small blocks. The ones I have in my boat now are rated at 290hp at about 4000 rpm and 387ftlbs of tourqe at 2600 rpm. Now if your like me you know this boat is not a race boat and is a gas hog. I am running 13x13 props with a cup and am intrested in going to a four blade prop but do not know what size I should be looking at. Any suggestions"
 
"I put 4 bladers on mine, and

"I put 4 bladers on mine, and added a bunch of pitch at the same time, so I can't honestly say how much better they work. That said, the props are what's considered 'over-propped' by the "experts" (those guys from outta town). The gas mileage mine gets is very good compared to my many friends with similar boats: I get 1.2 mpg at 20 mph (32 foot sedan with twin 360 Chryslers).
WOT rpms are well under 4,000, but the boat leaps out of the water with full fuel and passengers aboard, so... If it struggled to plane off I'd back off on the pitch.

From what I've seen of those neat little Chris Crafts (and nearly bought one myself), they do not struggle to plane off--even with 305s. So more pitch will save you some gas $$$. So would repitching your present props instead of buying news ones. It's kinda like going to overdrive or higher gears in a car.

Jeff"
 
"Jeff,
I feel that I am unde

"Jeff,
I feel that I am underpropped. From what I have been told by serval Chris Craft suppliers, the 13x11 was standard I have 13x13. Boat runs well with them even when the boat had the tired old 350. Now with more hp and tq I am still not sure what four bladed prop to use. with the 13x13 I get 1mpg, thats not too bad but I fell that it can do better."
 
"Jeff, Do yu know how to get i

"Jeff, Do yu know how to get in touch with Richard Dragolic ?"
 
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