Liberator 241 top speed?

14920 Views 52 Replies 24 Participants Last post by Kidnova, May 18, 2022

Religion

Discussion Starter · Jun 4, 2008

Hey everybody, I bought my first boat a few months ago ('89 LIberator 241) after spending last summer on an '88 211. The previous owner repowered my 241 with a 7.4 MPI so i thought this boat might scoot. Well I was wrong. The 211 would do 55 GPS'd anyday with 2 ppl. I can only get my 241 up to 38 GPS'd with two ppl and full tank of gas. The prop is a Merc Marine Offshore Series 48-825902A 46 21P 4 blade aluminum. 1.50 ratio. My max RPM has been 4700. Doing the math I've got about 39% prop slip. The boat does have bottom paint which I thought might add some drag. Any suggestions on how to make this boat faster or is this what I get for having such a big heavy boat and a stock big block?

Thanks for any input.

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markt111

· #2 · Jun 4, 2008

sounds like more than a prop problem with that low of performance, is your tach correct? engine running on all 8?
I had an 88 211 Libby that had a mildly built 300 HP small block that only ran low to mid 50s GPS, mine ran best with a Ballistic prop but your heavier.... it did have that built in hook from the factory like most of these hulls(more like a built in trim tab)
after you determine if your engine is ok try any stainless 4 blade you can get your hands on, Rev4, Bravo, Mach
I still have the Ballistic if your interested

Super24

· #3 · Jun 4, 2008

I'd try another prop. Here's a chart to give you an idea of what to try.

http://sites.mercurymarine.com/portal/page?_pageid=126,49355,126_49365&_dad=portal&_schema=PORTAL

RSCHAP1

· #4 · Jun 4, 2008

55 may be optimistic, but should do better than 38. I would look at prop. RPMs in the ballpark by the sound of it. Bravo drive now? 1.5 ratio?

cfm

· #5 · Jun 4, 2008

Don't take this the wrong way if you know, however, I have to mention it since we have had a few people come on to the site with performance issues just like yours. After mucho time, it was discovered they did not know about and/or use the outdrive trim and tabs if so equipped.

Religion

Discussion Starter · #6 · Jun 4, 2008

First let me say I've only been a member of this site for a couple days and I love it! Thank you so much for your input.

Now to answer a few q's: Yes its a Bravo One with 1.5 ratio.

And no, I didn't take it the wrong way. I do know how to use trim and trim tabs.

Now about checking to make sure my tach is correct. Since the MPI has a rev limiter can't I rev it in neutral til it hits the limiter and see if that corresponds to the reading on the the tach. I guess I just need to know what the rev limiter is set at. 4700?

SweetEmotion

· #7 · Jun 4, 2008 (Edited)

THats crazy your only hitting 38 GPS I got a 241 Liberator with a 454mag 420hp carbed hittin 57 GPS all day long at 4800 rpm. I would switch to a stainless steel 3-blade Mirage Plus 23p. These Libbys like the 3 blades. Post some pics of your Libby so we can see.

Oh yeah Welcome to the club, theres alots of Libby lovers in this club.

As far as checking your Tach I would take it to a pro reving ur boat up that high sound like an unnessesary risk. Just my .02 cents

FastEnough

· #8 · Jun 4, 2008 (Edited)

Religion said:
Hey everybody, I bought my first boat a few months ago ('89 LIberator 241) after spending last summer on an '88 211. The previous owner repowered my 241 with a 7.4 MPI so i thought this boat might scoot. Well I was wrong. The 211 would do 55 GPS'd anyday with 2 ppl. I can only get my 241 up to 38 GPS'd with two ppl and full tank of gas. The prop is a Merc Marine Offshore Series 48-825902A 46 21P 4 blade aluminum. 1.50 ratio. My max RPM has been 4700. Doing the math I've got about 39% prop slip. The boat does have bottom paint which I thought might add some drag. Any suggestions on how to make this boat faster or is this what I get for having such a big heavy boat and a stock big block?

Thanks for any input.

You should be doing better than 38mph. But still you have got to remember that our boats are a big hunk solid built fiberglass and are in no way a speed hull. My 211 is very deep and heavy. Your 241 is bigger and heavier. Compared to todays size measurements standards you are running a 29' beak boat That is why libs they last forever if the hulls a kept dry. With my 330 454 I could only get 55 with 25" Mirage Plus 1.50 drive that I bought for my re-powered 454 mag that is going to have around 450hp. If I can run around 65 gps I will be very happy.

SweetEmotion

· #9 · Jun 4, 2008

65 might be asking for alot 60-62 I would think is more realistic. Like you said big and heavy, but I love the cockpit room, and the cuddy is good size too.

offshore ginger

· #10 · Jun 4, 2008

RSCHAP1 said:
55 may be optimistic, but should do better than 38. I would look at prop. RPMs in the ballpark by the sound of it. Bravo drive now? 1.5 ratio?

i agree ............................. put remove the bottom paint , unless you plan on keeping her in the water all the time . I have a friend same boat , 330 H P , 23 P mirage low 50's

Mild Thunder

· #11 · Jun 5, 2008

I had a 241 with a 540CI 600HP big block and bravo drive. 70mph on its best day.

With the 7.4MPI, which I belive is 310HP, id say you should be around 50mph with botom paint. Ditch that prop, try a 21P mirage plus, or a 19p mirage plus three blade.

Slow boats, but built real well. try a mirage prop and let us know the results and go from there

Religion

Discussion Starter · #12 · Jun 5, 2008

offshore ginger said:
i agree ............................. put remove the bottom paint , unless you plan on keeping her in the water all the time . I have a friend same boat , 330 H P , 23 P mirage low 50's

I would love to remove the bottom paint. How do i do that without damaging the gel coat? I've heard that once it's on there it's on there?

SweetEmotion

· #13 · Jun 5, 2008

I would think you could wet sand it off, would be alot of work though. Then buff it a couple times after. Or take it to a pro, that might get expensive. I think your problem is your prop, I know a couple guys with bottom paint on their Libbys, and they`re running alot better then 38.

Post some pictures of the painted hull so we can see.

offshore ginger

· #14 · Jun 5, 2008

soda blast very safe and will not damage the jell, sand and buff . :winker:

Religion

Discussion Starter · #15 · Jun 5, 2008

I'll try to get some action pics next time out, but its looking pretty sweet now after buffing the hell out of it and polishing the window frames. This pic was taken before I did all the detailing.

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Black Wishbone

· #16 · Jun 5, 2008

I am going to throw one more out there and I hope I am wrong it could be water logged. If you can get it weighed.

Steve

SweetEmotion

· #17 · Jun 5, 2008

Looks pretty good Religion, are you going to stay with those Religion decals on the sides? If you want to go back to the 241 Liberator decals let me know I just had Raceline Digital make new decals for mine turned out great. They should still have the measurements from mine to crank out new ones for you.

Check it out

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SweetEmotion

· #18 · Jun 5, 2008

Hows the Jimmy work for towing that big azz Libby? Looks a little under sized.

offshore ginger

· #19 · Jun 5, 2008

SweetEmotion said:
Looks pretty good Religion, are you going to stay with those Religion decals on the sides? If you want to go back to the 241 Liberator decals let me know I just had Raceline Digital make new decals for mine turned out great. They should still have the measurements from mine to crank out new ones for you.

Check it out

:laugher: :laugher: :laugher: :laugher: :laugher: thank's i was going to ask that same question :a9:

offshore ginger

· #20 · Jun 5, 2008

SweetEmotion said:
Hows the Jimmy work for towing that big azz Libby? Looks a little under sized.

:iagree: untill he blow's the transmission :laugher: :laugher: :laugher: :truck:

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