Ref. Post 8.

In that case, should all of them porpoise at that speed?

The C.G. is the key !

L.S.

The CG would be the same with a 502 as an Hp 500 correct?

A buddy has a 98 gun with 625's and it has a porpoising issue to. It also has a full cabin. When speaking with Martin Marine they claimed it's a bottom issue and that they could "Correct" it with Blue Printing the bottom.

The bottom of these boats were designed when the boats used TRS drives.Because of the transmissions,the motors and weight were more forward.When the Bravos came out,the weight distibution changed,and so did the ride.That is what I am told.I had the nicest 2000 Topgun out there (Lip-Ship half-cabin with the new T/S lighter layup and 500 EFIs that ran 78-79, and in certain conditions,that boat porpoised.The only way to correct it was to tuck in the drives and give it some tab.

So a Bravo drive non-Kevlar conventional hull with a full cabin should put more weight forward and possibly ride better than a lighter cover girl cabin with Kevlar ? yes/no ?

ed

my 92 with 502/ 420hp bravo's ran 64. i never had problems unless you over trim. went to 600's low 70's no porpoise, 700's ,imco lowers 1 inch shorters lab 28"s gps says 81.5 i still don't get any porposing

Our 95 w/3A's/600SCs & full cabin porpoises. I haven't had much time to dial it in and it "could be" user error but we ran it for two straight days in Havasu (lake/flat water) and I had to run tab to get it to stop porpoising. You just can't run the big non-stepped boats "drives out/tabs up" like you can smaller or stepped boats. I would think you would at least need to run tabs even. There's a sweet spot, but like I said, I haven't had time to dial it in Hopefully soon.....

my 93 tg has merc.425's with trs's and full cabin, it has a sweet spot too, but it still has porpoising problem unless dialed in. can we prop our way out of this???