i have a 1986 offshore 24 with twin 1987 150 yamaha 2 strokes. One outdrive is counter rotating. What would u think the top speed is? I cruise at 4K and the gps is showing 30 mph. If i run the engines at max rpm which is just under 5500 i can do 38 to 42 mph. Maybe it's just me thought it would go faster with twins.
top speed 86 offshore24 with twins?
- Thread starter lime4x4
- Start date
I had a 95 252 Sailfish with twin 175's. Your speeds are exactly where mine were. Compaired to other boat manufactures the Grady's are fairly heavy, and are not speed boats
Had an 1988 Offshore with a single 1988 Evinrude 225 that was freshly rebuilt. If memory serves me correctly the boat would top out at 44 mph with light load. The boat had a bimini top and engine was mounted on the transom (no bracket), bottom paint was super smooth.
I would expect about 46 mph lightly loaded with twin 150 outboards with the same setup. Remember twins weigh more and have twice as much drag in the water. I do not recall the maximum rpm range for your engines, is it 5500 or 6000?
I would expect about 46 mph lightly loaded with twin 150 outboards with the same setup. Remember twins weigh more and have twice as much drag in the water. I do not recall the maximum rpm range for your engines, is it 5500 or 6000?
My 94 Sailfish with 200HO E-tecs does a bit better but these should be compared to 225HP motors. My performance plots are below and it topped out at 50MPH using my older 19" Viper props and 48MPH using my current 17" Rebel props:
http://www.etecownersgroup.com/post/reb ... 1278837256
http://www.etecownersgroup.com/post/reb ... 1278837256
My other boat is a 86 searay 268 cabin cruiser with a single 350 alpha drive. The boat cruises at 25 mph with a top speed of 32 mph. Just thought the grady would be faster. The boat is quick thou. She hops right up on plane is doing 30 mph so i can'r complain. Max rpm's for the yamahas according to the manual is 4500 to 5500 rpms
I have a 23 Gulfstream with twin F150's and I can touch 40 with them wound up....shorter fatter hull will be slower than longer skinnier hull with same power...
Hard top or No Hard Top, that makes a difference too. I have a 1982 Seafarer 226 retrofitted with a Stainless marine bracket, Single 225 Yamaha, 15x17 prop runs 30 at 4000 and 44 at 5500, no hardtop. Seafarer and Offshore look to be the same hull mostly except for length.
