Groper

Should I be asking this in the Tech Section ?

I just took my 30' for a first run, with the motors level or with neutral trim, and "No Tunnel Tab" the Boat would porpoise from 35-40mph all the way up to 80+mph.

I could control the "Hop" with the Tunnel Tab, but it would take a lot of Tab, at 90+mph it would take all the Tab I have to level it out. The water conditions were smooth with some boat wakes and some wind chop but it was really calm.

My question is, maybe the motors are up too much on the Brackets, and that may be causing the Porpoise ?
What is the sweet spot for the nose cone(s) in the relationship to the bottom of the Sponson using a straight edge?
1", 1-1/4" ,1-1/2", 1-3/4" Up ?

Thanks in Advance

obrien

We used to set the engines about 1 1/2 to 1 5/8 above the bottom of the boat if I am remembering correctly. Did yo try adjusting the trim at lower speeds to see if it changed the porpoising at all? Where are the batteries located in the boat? What kind of gear is stashed in the rear of the boat? You shouldn't see any up in the 35-45 mph range. The hop will be much more noticeable in flat water.

Groper

I have not measured the "Height" of the engines yet.
Trimming down did help, but I kept them level most of the time as we were cruising at 60-70mph.
The Batteries are mounted right behind the rear seat in the in the large open compartment.
No gear in the large compartment, Ice Chest or anything, It's completely empty, Two life vests under the Bench seat and about 30gal of fuel in each tank.
I will measure the motors this week, I have a feeling their too high.

Thanks Bill

OPS VZLA

Whats the prop size/style are you runing?

Groper

15 x 30 3b Cleavers

mikesufka

I have a Spectre 30 with twin 300XS's. The center of my prop shaft is 1 1/2 inch above the bottom. Props are 15 X 32 Merc Cleavers (3 blades).

As far as the hop - cold weather, chop, or wind will help. Glass calm, hot, and heavy with gas, people, etc... will make it worse. Mine rides great until about 50 MPH, then it hops until 75 MPH or so. 75 MPH - 100 MPH is smooth.

Hope that helps. Will be listing my boat soon if anyone is looking. Want to do something different.

Mike

X-Rated30

My hop was 45-75 and it would straighten out by itself. Boat had no tab and didn't need one. Everything said above is correct. My guess would be motors too LOW.

Groper

What runs the best as far as Props turning in or out ?
Any handling issues In or Out ?
It seems that most Cats run faster with Pros turning in ?
Adding the DBR stage 1 kit to the motors right now, and going up to BBlades 32" 3b Cleavers, it should be interesting to see what gains I see.
Thanks

bulletbob

My center pod Talon hops in calm water with or without alot of weight in the boat. Some say center pods don't hop. They do in flat water. With a little chop the hop goes away. My motors are 1 5/8 " above the sponson. It sounds like your headed in the right direction with the props and if your propshaft is level with sponson your motors are to low. Setup is the fun part. Enjoy your new ride!

Bob

obrien

We always set up the 30 ob's turning out