23cc with twin yamaha f150's, numbers???

[doodlebug]

When I originally set mine up with the 250's they were turning in. Way too much transom lift would dance on the Back end and would not lift the bow 10 mph slower. Don, we ran from the St Pete peer to the Gandy one day wide open, needed ac it was hot out there. Not a wiggle smooth as could be. Miss running them monsters but not feeding um

[Briguy]

You need a set of stern lifting props.

[77SceptreOB]

I have a friend with a 23' SeaCraft "Savage" model which is basically a Sceptre that has had the windshield removed and a center console added. He runs that exact setup (twin Yamahas F150's) the boat seems ass heavy and sits at rest pretty deep in the water in the stern. Very noticeable, even with the weight of the cabin up front. He does have an Aluminum hardtop/tower though.

The hole shot is pretty strong, but not 2 stroke strong due to the weight. He gets about 50 mph at WOT which I think it pretty good. I don't know what RPM he is running at WOT. But based on the hole shot and the WOT, he might be a candidate to run a slightly lower prop pitch to help with the COG/weight so far back as his motors are mounted on a non-floatation bracket. IMO, its border line too much weight back there.

[FAS]

First the bracket, and twins, take into consideration the location of the fuel tank.if there is a well or storage bin forward of the console.tank is aft,batts etc....that boat is gonna sit a lot different than most.nice look but whats best for a 23

[Briguy]

If you are chine walking at top speed you might want to have someone sit
near the bow and see if the weight up front cures it.

[Fr. Frank]

Denny hit it pretty well.
The lateral instability inherent in a deep-V hull with no flat planing surfaces is most noticeable in smooth water. Choppy water will actually give you a more stable ride. The hull rises up and tries to ride on what is effectually two points of contact: the keel line of the v-hull and the point mid-way between the two propellers which is the effective point of thrust.
Here's a couple of notes you may already know:
a) Having outward rotation on twins helps with stability and steering, but creates a bit more drag.
b) You want approximately 3/4" - 1" of toe-in for each 24" of separation of your motors.
c) Deploying your trim tabs slightly as speed increases creates two additional small points of stabilizing drag that actually reduce your speed only negligibly and stop/reduce oscillation noticeably.

As I said in an earlier post, I sold a 23' SeaVette back in '83 that the customer took to Frank Brown for rigging with twin 300hp 3.4L Mercs. It reportedly could hit 77 mph after tweaking.

Back in 1984/85, my own 23' Savage with twin Mercury 225's could hit 57-58 mph with the bimini down.

[ericallen01]

The twin setup works well on my 23' Tsunami. 175 twin mariners on a Gil bracket, CR prop on the port engine, set up with hydraulic steering. It's a different boat with the bracket setback. Trim tabs help the stern lift, as does working with gas tank centre of gravity forward as needed. Had to reinforce the transom / stringers with some angle bracing.