Thanks Knot, nice read. Sure could use a bit more real world numbers by changing over. I will time my props for next season, maybe this if I get the urge again. Keeping my eyes open for the 25 XR now. Kind of makes me think, I have a good 20% prop slip now, if the 25 reduces it down to 15% or a bit lower I may need 24's. Don't know

I just can't believe your slip is so high. If you did not modify your stock drive height, I wonder if something is up with your current props. I know that out of the box, standard 3 x 3 prop sets are notoriously out of balance and can have variances in pitch across the blades.

Depending on what calculator I run, I am between 8 - 10% slip.

sorry somehow I deleted instead of edited
Ive been dealing with a similar challenge on my fat pig and have read a ton. Some publications say that 20% on a cruiser hull is normal at top speed and performance hulls interrupt the water less and shouldn't be used as a comparable for prop slip. This may also contribute to the lack of top speed increase that AllDodge and I both saw after our re-power. I also think I am calculating wrong, most of us are trimming up for that last mph then using those numbers to calculate slip but if I trim down slightly I may lose 200 rpm and only 1 or 2 mph, as a result my slip numbers can improve significantly. Then there is the weight and fuel load that most cruisers are carrying during the tests. At the end of the summer I am going to run a quarter tank and empty my crap drop my bimini and do a true run in both directions documenting speed and rpm at 1000 rpm intervals and I bet my numbers become much more normal "for a cruiser" I suspect the same thing would happen with Al Dodge. Then again what do I know? lol

I have calculated at 3600 thru 5050 rpm and for the most part it stays about the same amount of slip. Been using bblades calculator to get the numbers. Went out this after noon and checked the prop timing, While it doesn't appear I'm dead on maybe one tooth off. Something I'm going to check out when I pull the boat out this season is the height or the XR upper. As before I have my original B3 lower but a new XR upper. Don't know if the height of the XR is the same height as the standard B3 upper.

The boat is lighter in the stern from the water soaked foam and I it is real touchy with the trim, takes next to nothing to start proposing at 3600 rom and above. Anything from 4500 to WOT it not so much an issue with the trim. This is also having tabs all the way up. If I put the tabs down to take off it takes a bit longer. With the previous power I had to have the tabs down to get up

AllDodge, since our talk I pulled the trigger to work at getting mine dialed in a little better. I have some news, but I am still in the testing stages. I spoke with Chad Hill in regards to his Signature 4 x 4 wheels and decided to order a set. I bolted them on and put some hours on the boat this weekend, but the bay was snotty and couldn't get some WOT runs. I did get rid of the slip getting on plane, in fact its impressive getting on plane using the same pitch as i had with the Merc 4x3s. I also can get into aggressive turns like I use to with my B2 before the repower. The boats overall behavior was drastically improved also. I was running in a 3' chop and it let me be able to trim on top and stay steady without porpoising issues. I am working with Chad of what is the next step. He offers an exchange service in which I send these back and either tune them or send me another pair to get really dialed in. I almost feel with his wheels I can go up to 26 pitch which should give me a boost in speed and get me right where I want to be with still improving how it pushes on plane compared to the 4x3s I was running for a while.

I can keep you posted, but I would really consider this an option. Tell him Tom from Formula Owners of New Jersey directed you his way too.

Check out the full resto of It Don't Come Easy here..... http://www.formulaboatsforum.com/VBF...y-Formula-26PC

Still doing research on which way. Going done to the dock later to measure another boat on a lift which has XR's. Something just doesn't add up and need to figure out what is happening. Wouldn't mind trying the 4x4 or the 4x3 but need to find out what is different. Was thinking of putting my 3x3 24's back on just to see if the boat cruises like before. I use to run 3600-3800 doing as I remember correctly 34 to 35mph, which puts me in the 14 to 17 slip area. Now I'm turning the same rpm doing about the same speed so my slip is high, just something is off.

Did look at your build, very, very nice work, cudo's and nice family

I havn't been on the Formula forum for a while since the last weird happing on a thread with GENSET. Still don't get it but oh well, plenty other things here and on iboats

I would give the 4x4s a shot. With my luck of actually buying something that works, I admit I was skeptical but needed to do something because I just wasn't satisfied yet. I know there is some left. Most people would hop on my boat and be ecstatic but I just know there could be something left on the table so I am going to give it one last shot dialing her in.

Your HP and TQ may be located at different RPM levels with the new build which will throw your comparisons to the previous setup off. Ultimately you really need to get her to grip, with that much hp you should net some good results speed wise once you do.

Thanks for the kind words, this is why I hopped on here because I can appreciate what you are trying to do.

Ah i just had to look back and see what you were referring to and I see that. Hey it's silly Forums, lots of different views. I bumped into a few posts through in this thread that were questionable but.... like i said it is Forums, kinda part of the game here. For what negatives you will come across you will get your positives.

No issue with someone saying something that upset me enough to not come back. Don't really remember what it was all about but it came down to I explained my reasoning behind comment. The moderator simply gave a comment which resembled something like (I don't have to explain why) and then closed the thread, wasn't even my thread. So figured if the guy running the show gets that way maybe I should stay away. I still pop in every once in a while

A 4x4 or 4x3, I'll try one and bblades is showing a set of XR's for 720 I think

Hmmm your work is so thorough i almost hate to say this but i must pee in the punch bowl so to speak.You need clean your hull bottom up ....strip the paint the amount of drag it's creating is huge and if you go there it would be wise to see or look for hook...When you trim and she's bouncing or falling off is drag more than probably....now i know how much work that is but it's highly suspect......

Not worried about peeing in the punch, appreciate the comments. While the boat bottom does have a hook the bottom while not smooth its pretty clean. Don't see how bottom paint has much of an impact on a cruiser doing 35mph.

It could be as simple as the 26 pitch I'm currently using have a problem which was not found with the eye ball. I could put the 24 back on and it should run like it use at the same rpm. Old 24 turning 3600 rpm doing about the same speed as the 26 do now.

Did find out that the XR upper is the same height as the standard bravo, so prop is still at same height as before