underpowered 454?

[haulnazz15]

Re: underpowered 454?

Lol, I absolutely love all of the bickering concerning the LOA of two boats that are within a foot of each other in running surface and 4 years different in manufacture!! The Wellcraft is a 26 ft boat, not likely including the bow pulpit or swim platform it may have. The Sea Ray is a 26'8" boat, not including the bow pulpit or possible swim platform. They probably weigh within 500lbs of each other.

the only real difference is the Bravo 3 vs Alpha issue, which is mainly just a single screw vs. counter-rotating single screw issue. In any case, I'd say if he is able to hit 5K on a 454, he is probablu underpropped and could grab a bit better hole shot and possibly even a few mph by propping to something with a little more grab and get the WOT rpms closer to 4500, not 5000.

Edit: For the record, NADA shows the 268 at approx 5500lbs, and the Wellcraft at 5000lbs (not inlcuding what particular options each boat has). So I was pretty close.

 

[TilliamWe]

Re: underpowered 454?

You think you're close on the weights, but I'll tell you that the Sea Ray weighs A LOT more than 5500lbs. Closer to 8000lbs, actually. My dad is camping somewhere in NY, so when he gets my e-mail, he'll remind me of the weight of his 268 and the prop he used.
And the difference between an Alpha One and a Bravo 3 is HUGE! Not something to be taken lightly. The B3 is superior in EVERY way, and I am fairly certain that's why 26aft made the radical change from an Alpha to a Bravo 3. The drive alone would make the original poster's boat completely different. it would plane faster and hold that plane at a lower rpm.
I do agree that at 5000rpms, that ol 454 is turning a little too fast. Propped to hit 4600rpm would be better.

 

[lime4x4]

Re: underpowered 454?

I have a 1986 searay 268 weekender. I'm running a single 350 vortech engine with an alpha drive. The prop is a ss mirage plus 15 3/4 x 15. My max speed is 35 mph. I can cruise at 25 mph and still be on plane at 3200 rpm,s. Using gps for speed info. Fully loaded with gear and fuel i'm up on plane in 8 seconds. My boat and trailer weigh in just a tad over 9200 lbs

 

[jtmarten]

Re: underpowered 454?

Edit: For the record, NADA shows the 268 at approx 5500lbs, and the Wellcraft at 5000lbs (not inlcuding what particular options each boat has). So I was pretty close.

Thats interesting! Both of these boats are huge in comparison to mine, although they're roughly the same length, and NADA shows 5200lbs for mine. I wonder if they just assign (x)lbs/ft??

 

[TilliamWe]

Re: underpowered 454?

Thats interesting! Both of these boats are huge in comparison to mine, although they're roughly the same length, and NADA shows 5200lbs for mine. I wonder if they just assign (x)lbs/ft??

NADA gets their weights from the boat manufacturers, who just make them up.

See the post above yours to see what a Sea Ray 268 really weighs.

 

[TilliamWe]

Re: underpowered 454?

Frankie, my dad was able to reply to my e-mail and her's what he said:

"Billy,
Top end was about 41 mph with a 17 inch prop running thru a 1.50 Alpha. I used a 16 aluminum and it did the best. About the same speed but it let the engine run higher rpm. It weighed at least 8000 lbs.
Dad"

So it does appear that I was incorrect when I said you wouldn't hit 40mph. It's possible.

He doesn't state it, but I "think" they were both 3 blades. However, he did have a 15pitch 4 blade for it too. You might want to keep a 4 blade, as more blade area is a good thing for your boat. But experimenting with 3 blade props wouldn't hurt.

 

[Frankiea87]

Re: underpowered 454?

first off.. the whole wellcraft subj. needs to go to its own thread, noone cares about it..

2nd.. thanks everyone for trying to get back on subject. i appriciate it.. i think maybe i should try a different prop though? if so which type?/pitch?

 

[sethjon]

Re: underpowered 454?

What prop do you have? Al or Steel? Whats the pitch?

 

[TilliamWe]

Re: underpowered 454?

first off.. the whole wellcraft subj. needs to go to its own thread, noone cares about it..

2nd.. thanks everyone for trying to get back on subject. i appriciate it.. i think maybe i should try a different prop though? if so which type?/pitch?

I would look for a 16 pitch prop with as big of a diameter as you can find. Big "elephant ear" blades would be good too, probably.

 

[thatguy]

Re: underpowered 454?

Growing up, my father had an 88 sea ray 268 sundancer powered with a merc. 330hp alpha 1 drive. My father played around with props and ended up swinging a 16X16 with great luck. I DO NOT know what gear ratio the drive was. The drive had been replaced at least twice. Top speed with the 16X16 was about 42@ 43-4400 RPMs, the boat climbed up out of the hole pretty good too. With 2-3 people on board, you could run up on plane at 2600 rpms in the low to mid 20s and be in the single digit fuel burn, around 8-9 gph.

Tom

 

[HT32BSX115]

Re: underpowered 454?

hey guys i got a 88 sea ray sundancer 268.. 454 merc 7.4l with alpha drive with 4blade prop.... i feel like its not getting top speed it should be getting as people say. at 3500 rpm in not even at 20mph and cant get on plane... about 4500-5000 rpm ill be on plane at 25mph and then full throttle 25-30mph. i feel like i should be able to hit 30mph at 3500rpm.and almost 40 at 4500rpm or am i wrong?

Howdy,


Maybe a little more info might be in order.


How long have you had the boat? (did you just buy it?)

Did it EVER go 40 MPH? (or did the previous owner make that claim?)

Did you always have the current drive and prop on it?

Do you know the drive ratio? (you don't seem to know if it's an Alpha or a Bravo)

If it really turns 5000 RPM, something else might be wrong (like the wrong ratio drive). Did you replace the tach? (have you tried a known tach?)


Have you measured speed with GPS or other known speedometer?

Until you know the above info, we're sort of shoot'n in the dark here......

By the way, if it is REALLY an 88 model year engine and drive it could still be a 454/Alpha. The engine and drive could be an 87 model year. Boat builders frequently use last years model engine and drive and Merc did do 454/Alpha in 87. I believe 88 was the first year for the Bravo.

 

[tarheelebbtide]

Re: underpowered 454?

If his boat has been sitting in the water for a "few months" since he bought it, I'm betting that bottom is more fouled than he might think. That can make a huge difference. It does on my 20 footer and that's in fresh water (not sure where this boat is) from the beginning of the season to the end. I'll lose a few mph every year from beginning of the year (when it's clean) to the end (when it isn't).