311 Top Speed Question
 

I just picked up an 88 311 with 420's. I put it in the water today and went for a little run and only got about 55mph out of it. It has the factory 21p 3 blades on it. I was at about 1 on the tabs and 4 on the drives. I could spin the motors right up to about 5,000 no problem. I know it would go faster if I gave it more time wide open but I didn't have much room and really didn't want to wind it out for any length of time quite yet. It is bottom painted but its clean, no growth.

My question is I thought this should be a high 60's boat so is the bottom paint hurting me that much, I thought it was only a few mph. I was planning on taking it off anyways.

also about 1/2 fuel, six people, salt water, pretty calm, stock VDO was verified with my buddy's phone.

Thanks

I am spinning 23's and 25's on mine. I change them from time to time depending on what I am doing. I like to run the 23's most of the time. I can get it up to about 69 with a best or 72 on the speedo. The speedo in my boat is fairly accurate. I trim it up almost off the indicator for max speed runs. Tabs all the way up. I have the same year as you.

The bottom paint is not going to loose you much speed if any. People get all worked up about it but honestly if you are going to leave your boat in the water you are better off having it. Your boat will be faster with the bottom paint then with a beard of crap that will grow on it if you have no bottom paint. My boat has bottom paint and my buddies does not and I am always faster and his boat is a year newer.

Are you running Bravos on the '88? My '89 311 ran 67 mph all day regardless of fuel/load with the factory 365 hp 454 magnums and 23p Mirage props.

You are way slow. Mike turned 26" Bravo 1s to 4800 and 70 mph with stock 502 MPI's (415hp). My buddies 87 with TRS drives and 330's would run 60+ all day long.

88 420 boat would be TRS

I imagine its a combination of things, props a little too small for top speed, engines may be a little tired, drag of TRS drive and tranny compared to a Bravo ,and not giving it enough time/room to get those last few mph.
In my case I get to 60 quickly but it takes a while and lots of trimming to get that last 8-9mph .

It is a TRS boat, motors have just about 500 hrs, but pulled real strong the whole way. That pretty much answered my question, thanks. I'm just used to my fathers Fastec that pretty much gets to 70 as fast as you can push the throttles. I guess next year I'll just give it more room to run.

Thanks

Try and find some 24 pitch Bravo 1 props.

My boat will run 68 all day with 25p 3 blades. The best ive seen is 70.8 gps with just my wife and.

311 top speed
 

My '89 with 454 mags and Gill exhaust will run 65 to 66 with either 24" bravo ones or 25P mirage 3 blades.My buddy had an '88 with 420's and trs and the boats would run dead even at WOT.60 mph comes up quick, the last 5 take some room and some trim/tab adjusting.

I have a pair of 25p Mirage props with 8 hrs of time on them since new if interested. They are IMMACULATE.

you'll need more trim on the 311 hull ... mine is no tab for top end and 7-8 trim but its a Bravo boat .....I would think you will need at least some 23's .... I have some with new tune and hubs ..... 425.00 shipped ....m

Thanks guys, it depends on whether I can go for another run. I wanna get all I can out of it before playing the prop game, just so I have a solid base line. Unfortunately that might not be until spring, but thanks for the offers and I'll keep you posted.

I have been out with jon on his 31 nice ride, in the spring if you want to try props call bret a bblades he can send you out one or two pairs to try and then if you want more he can lab them for you. say stock 23s your at 70gps but labbed 25s might give you 72. also with a deep drive like the trs the merc rev 4s work real nice there sometimes faster than the mirage and have the vip of a 4 blade. oh those 420s are nice and easy to make 500 to 575 hp out of changing cam/ intake/ and sometimes carb but the 800 you have should work to these hp#. we will have to hook up I live in easton right on the WB line theres a bunch of us that go out of plymouth/fairhaven new bedford/ east providence/ fallriver these are places with boat ramps. its always fun to have more than one boat going out together ,in case of a break down you go to the closest ramp tie the boat up. then get a ride back to trailer it beats waiting for sea tow and have a 4 hour tow haha. if you want give me a call I might have get together in the next few weeks at my house. you could meet some nice people from the board and jon could give you more info on your boat. my cell is 617 833 3327 Art. I had a stock 502 mag 390hp at the prop. rebuilt by Jim Ried in whitman we did about two changes with stock block stock heads with mild porting. 1st was all MSD stuff, stock block mod heads, dart intake and switch to hyd roller set including cam and a stock 800 or 850 carb it was 1995. we got 585hp next was a switch to 850BG carb we got 595hp. 3rd time it was bore the block to a 509, isky cam, merlin marine 310 heads pocket ported we got 637hp with 850 bg carb then a 1050 dom was good for 650hp last a CFM performance carb 670hp. Jim has some real good prices too. freshen a motor new rings, bearings, swap to hyd roller and maybe intake starts about 3000 and up. anyways call me if I can help with anything about the boat ,boat ramps what ever. GOOD LUCK Art ps theres a nice ramp down at sommerset or across the way at fallriver its not to late to run mt hope bay is where outerlimits was testing the other day nice 1 to 2 footers also there a run down in conn this weekend on the conn river theres some local guys going.

Thanks for all the information, and I think I met you before, were you at the Borden Light Poker Run this year? We were wearing safety yellow in the Fastec.

I don't care what anyone says you WILL loose speed with a painted bottom! I gained close to 6-7 mph with my 242 when I stripped the paint off. This was with a fresh engine and everything else stayed the same. The only paint IMO you coould maybe use and not loose MPH is VC-17 but it only works in freshwater. Either way loose the paint and gain some speed.

Hey, what do you have in your 242??

That depends on the bottom paint. If you leave your boat in all summer long, the growth that you get with out the paint will give you a much larger loss in speed then what you loose with bottom paint. There is also a HUGE difference in bottom paints. Some will slow you down but others not so much. I had bottom paint on my 311 and it runs the same speed the day I put it in vs. the day I take it out at the end of the year. My 311 is actually faster then my friends 311 that is a year newer then mine (only like 1-2mph or so). If you want to know whos bottom paint is the best look at what the blow boaters are using for their race boats (not the hard core guys they pull their boats at the end of each day).