28 twin and porpoise
#1
Registered
Thread Starter
Join Date: Jun 2010
Location: Near Naptown, MD
Posts: 66
Likes: 0
Received 0 Likes
on
0 Posts
28 twin and porpoise
Im getting pretty comfortable with my new to me 28 twin. I have one thing that is driving me nuts. When ever I am cruising below 60 the boat porpoise really bad with no to almost 3/4 tab down and the drives all the way in. It levels out around 7 or 8 on the tab settings which seems like alot of tab to drag to me not to mention the bow is lower than I think or would like it to be. If I try and pull the drives out it just seems to get worse. Now if I go faster than 60 even in a good size chop in the bay I can pull the drives out to 4 and pull the tabs almost all the way up and she flies straight and true. I have built 509's turning bravo one 4 blade 30P. Is it possible these props have too much lift causing the boat to porpoise?
#2
Registered
iTrader: (1)
from what ive read and tried it seems bravo props give you bow lift. i dont run much drive trim in my boat or it hops. i run the tabs level or just a touch above the hull. i have hydro props to try but 1 is getting fixed. might need a stern lift prop. or try running your props inward and see if that helps. supposed to give stern lift
#3
Prostreet, my pantera seems to act the same as yours under 3500 I have to have my tabs set at 7/8. That to me also seems to be alot. Its not till around 3800-3900 that I can trim the drives at all. I was thinking that my problem was that I have trs drives. I am running 4 blade 27's. I was wondering if a 3 blade prop would help with the ride by not giving the bow much lift. The conclusion that ive come to is the faster you go the better the ride.
Last edited by The Get Away; 08-15-2012 at 06:40 PM.
#4
Registered
very small boat for heavy twin motor's , when running below the sweet spot thats around 60 mph the boat wants to dig into the water , so run the boat the way it was made to be run over 60mph where it's on a good plane
#5
I too am spinning 4 blades and was told by b blades to try three blades. He said that they have more transom lift and less bow lift. I am looking for some three blade props for number 3's to try.
#8
Registered
iTrader: (2)
I think I'm lucky one here, I don't have any porpoise problems with my 28, the only way it will porpoise is if I trim out to much in FLAT water. Here's the sercet Trs drives with 2" spacers and props turning in. I'm losing speed with the spacers in and it sucks around the docks with the props turning in,but I'll take that over the porpoising.
#9
I think I'm lucky one here, I don't have any porpoise problems with my 28, the only way it will porpoise is if I trim out to much in FLAT water. Here's the sercet Trs drives with 2" spacers and props turning in. I'm losing speed with the spacers in and it sucks around the docks with the props turning in,but I'll take that over the porpoising.