28 Skater guys ...... HELP!
 

I am running a 28 with 300 promax's, sporty lowers, bolted on the transom. I am a real world boater, I run with lots of fuel and 2 to 4 peeps and assorted boat gear.
I have always been made to believe that the 3 litres on a 28 makes it tail heavy. with that thought in mind, everything I have done is based off this belief. I am running oil bags to the outside, just behind the rear seat bulkhead.
I just moved the batteries forward of the front foot rest. I have dumped the heavy Skater seats for Sparko's. Prior to moving the oil bags approx 3' forward and moving the batts 8' forward I have seen (one time) 105mph with full tanks. (Bravo 32's with vent holes)

The problem: My props are showing more slip, my motors are seeing the rev limiters, and I've lost 5+ mph. The boat does not respond to up trim @ high speeds. Have I moved the center of gravity that far?

Sorry for all the wind, Thanx in advance, NP

first thing to check is are the motors still perfectly boxed, thats prob your 5mph plus i never had luck with those props

I hear ya. I run my boat the same way. Have 3" setbacks. Try some 4 blade dewald clevers. He has 30 thru 34's and some thru hub 5 blades.
Another friend on here tried some and picked up 4 mph. I can give you his number if you like. He ran them on a 28 with opti's.

I like the Mercury four blade lab finished Cleavers 14,5 x 32. My boat is all original and flys nicely even with the 300X's and a full load.

I have a spare set available that comes with a spare 28' Skater:lolhit:

Boxed? The boat ran 102 with 3/4 tanks and 4 peeps the week before I moved the oil bags and batts. thanx

I have heard good things about the Dewalds.

I know you're trying to help, but I'm not sure 2) 28's is the answer. l.o.l. I've got a set of 14.5x32 merc 4 blades, I'll give it a try. Maybe they will have less tail lift. Thanx

Are you spinning the props in or out? Do you know what the rake of props are?
I tried a set of 34" 3 blade Mercury cleavers on my boat and they were 3mph slower than my 34 4 blade Dewalds.

Props are spinning out, don't have a clue as to the rake angle.
are you running 2.5's or 3 litres? thanx NP

FYI I'm spinning in.

Moving all of that forward, it sounds like you have lowered the angle of attack and now have more wetted surface and hence more drag=more prop slip.
How many batteries, how much do they weigh? I know that my optimas weigh over 50 lbs each. The fact that you lost 5mph and trim response with the move confirms your hunch about changing the balance.
I like running merc offshore cleavers on cats. I'd say go with the advice on the Dewalds or BBlades, and put the batteries and extra cables back where they were.
I've personally witnessed skater 28 w/300 promax and merc 3 blade 15x34 running over 110+

10-4, it's starting to look that way. Got any 15x34x3's
Thanx NP (p.s. could I just add motors?)

I wish I had 2 sets of LH RH for mine. I'm going to start out with 15X32 3 blade

I raced a 30 motion with 2.5's for years. To answer your original question, yes moving the batteries that far forward will absolutely make that much difference! 50lb eight feet is allot!!!!! The question is how does the boat launch and land? Yes you can get more speed with everything in the back but the attitude of the boat won't be flat. I ended up with a 25# bag of lead shot in the very tip of both sponsons. The boat was a bit slower in calmer water (1 to 2' chop or less) ...but... the boat ran faster over all conditions when the boat left the water as I could keep speed up with confidence of not kiting the boat. BALANCE IS EVERYTHING IN THESE AIR ENTRAPMENT HULLS! That being said, the way mine was balanced I ALWAYS ran with neutral or slightly negative trim letting the air lift the bow. In my opinion you do not want to have to run a tunnel with positive trim.

I completely agree. I run my boat in the ocean and have run bags as well. To answer your question I have 300xs's. Don't give up on the balance it will take different x dimensions and props to make it work.

Call Dave Dewald he will let you try a set. Tell him Ron from S Fla said to give him a call. His props will outrun Mercury ones any day and don't break blades. He will warranty them too.

I am going tp drop the motors a little to see if the props will hook up and carry the boat. Only cost a little time. I'll Call Dewald and tell him what I've got. Thanx

My boat always wanted positive trim, which is what lead me to make the moves I did. I'm going to play with x dim. a little and see what happens. Thanx