timucin

just installed twin big-block (600hp-each) engines to a 28 skater.Confused about the rear-weight?!?. As I see noone uses twin inboard on a 28 boat . does anybody have any idea or comment about this combination?

cobra marty

Pictures! I would think that it would be quite tail heavy. Why not small blocks or a single BB? Good luck on dialing it in as maybe only one other has been done.

eliminator219

Timucin,
Why not check with Skater, I think that they have tried a lot of different combinations and as I always heard their boats work.
I have a 28 with twin big blocks, Just dont have enough money to have a Skater Hull.. Sound like you must have a good ride, sometime let us know how it performs, Handling that is, Know already that it will fly.

Regards, eliminator219

timucin

off course I asked skater first but I think they do not want anybody to touch/modify their boats.I am in Turkey so it is almost impossible for me to take the boat to skater just for rigging etc.

They told me to buy 32 which I am not interested for the moment.Cause we made side-by-side closed cockpit + installed the engines + did the first layer of paint +just received the props planning to test-drive in maximum ten days .Boat is almost finished .More then new boat marketing , just need some friendly advice.

I am still not sure about'' how will the boat will stay on the water with that much weight at the back of her when not runnin'?? where will be the water level at the back?? how the boat will react when I slow down fast?? etc..etc...

Katdrvr

What drives are you using? Are the engines mounted all the way back on the transom? I think I would try to move the engines forward a little bit. Two big blocks in the back of a boat meant to have ouotboards is a lot of extra weight back there. I would think it will really want to get the bow in the air especially in the rough. Becarefull and slowly explore the handling charactaristics of your set up.

Gary Anderson

Tough to say for sure, but I've seen a lot of fast mid-size cats running a driveshaft. American Offshore, Spectre, even a Chris Cat with Bravos. Most were designed to run pretty flat and that much weight aft may not work well.
Gary

CigDaze

I'm certainly no cat or skater expert, but from a physics standpoint alone, I would be worried about some serious handling issues regarding longitudinal stability.

A pair of big blocks with bravos weighs about 1200# each, 2400# total which outweighs the 28 skater hull by 300#(2100# empty).

You may want to reconsider or question Douglas Marine further...

This is going to place the cg of the boat excessively aft(appr 25%-30% length from rear) and increasing the distance between the center of lift and the cg causing a positive pitch-up moment every time it leaves the water...

Brad Zastrow

I would love to hear how the boat handles this after your test rides. I suspect you will have problems in the rough water. That is going to be a very tail heavy boat. I have to ask, why did you do this?

boot

Post this in general discussion area and do a search there too on things like center of gravity, small boat with twins etc . There was a very helpful discussion there a while back on exactly what you are doing and all the "pros " jumped in to give some great advise .It was very good reading . Try it before you "fly it" !!

IRONMAN

Install as many lightweight components on the engines as you can, exhaust,intakes,heads and so on. Install all other heavy items like batteries more foreward in the boat if possible. many of the 28's are rigged with 3 2.5 outboards at 400lbs each. this puts 1200 lbs at about 10 to 16 inches aft of the transom depending on jack plates etc... If you are installing 2 500efi w/bravo's for example they are 1113lbs each, that will put 2226lbs but the center of gravity for the engines should be about 14" to 22 inches foreward of the transom. If you could lighten the bb's by about 200lbs each then the delta would be only about 630lbs and the cg of the boat would be in the ballpark with the one with the triples----- a proven setup. Good luck and we all woulld like to see some photos The Ironman.