79formula

I have an 86 Formula 242. It made 572hp@5600rpm. I can squeeze 73mph out of it at 5000rpm. I feel it could go a bit faster. The reason I think It has more in it is I have to drag the tabs to keep the boat in the water. The hull has had the hooks removed. With the tabs up it either porpoises when going slow, or if i throttle up the boat gets most of the hull out of the water and starts chine walking bad. I have cable steering and everythings tight, but I have full hydraulic steering coming tuesday. I am currently running a mirage plus 23p prop. I know thats a bow lifter. I am also not running trimmed way out. Even with the drive tucked in, it still has way more bow lift than any other 242. Would a Hydromotive 4 blade help put the bow down?

Here are some pics cruising aroung 50mph. You can see how little hull is in the water compared to my buddies 27 fountain (my 242 is the same size rafted off).

MILD THUNDER

iTrader: (3)

Have you tried a shorty lower?

79formula

I have not. I was going to raise the x 2" when I did the transom. The consensus was no gains with slower plane times so I didn't do it. I probably should have. How do you think a shorty would help?

MILD THUNDER

iTrader: (3)

When you raise the propshaft height, you usually give up some bow lift, and lose some drag from the lower at the same time. Two things that may benefit you. I would think that right now, if you just go to a stern lifting 4 blade, and get the boat to run "wetter" , with no other changes, you prob will go slower. The ultimate goal would be to run with the drive trimmed about parallel, not tucked in, or trimmed way out.

The only time I've heard of guys losing speed when going up in propshaft height, is if they get to the point the boat loses the bow lift it needs, or simply the prop is too high the slip goes thru the roof because it cant hold water. I'd imagine your prop is pretty deep right now, and doesnt sound like you need any help carrying the bow at this point though.

Its all trial of error with this crap, nothing ever works the way you think it should lol. Easiest and cheapest thing, would probably be to just try a couple different props before anything else. I just noticed your boat is a 1986. Initially I assumed it was a bravo boat. But maybe a TRS?

79formula

The boat was originally a 260/alpha boat. It's now a bravo boat.

79formula

I wonder if I was advised not to raise the x because most people have 454mags and want all the bow lift they can get.

MILD THUNDER

iTrader: (3)

Maybe. or maybe they still are running a hook in the bottom, and need all the bow lift they can get.

Black Baja

iTrader: (2)

X dimension is to low.

BenPerfected

There is a fix but it can be pricey, but likely less than you have already spent on more HP. In your pics you can see that inter-strakes are not in the water. This causes the boat to porpoise as the bow is now unsupported. This is called outrunning the bottom.The fix is to lengthen in inter strakes to where they just touch the water. Today, the porpoiseing is scrubing speed. Glass Dave in Toledo is the perfect shop to do the work. In our experience this could free up 5-8 MPH. If you noticed in a previous post, Glass Dave now works for free��. Free as in not wasting the the HP you already have but are now scrubbing speed as the hull is inefficient.

Tinkerer

You are comparing wetted surface of your boat to a stepped Fountain. Your boat doesn't have steps the fountain does. A boat with steps doesn't need as much bow lift and is designed to run flatter.than your straight bottom boat.
You need a shorter drive.