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Posts: 63
Location: Maribel WI | I have a 2007 1700 Esox with a 90 Optimax. In order to prevent the boat from porpoising, I need to have the trim almost completely down. I can come up a bit, but not as much as I should be able to. Im trying to determine if it is a prop, or mounting issue, or something else. My Max RPMs is about 5700 and top speed is 38 mph with one person and normal gear - when Im at my max trim height before porpoising. Feel like I should be able to get more out of it if I could trim up more.
The motor is mounted on the second hole from the top (so it could go up three more holes or down one) and has a 18 pitch Vengeance SS Prop (48-16988). Some people I have talked to suggested the motor be raised up, just looking for some "expert" opinions.
Thanks
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Posts: 3469
Location: Elk River, Minnesota | Hiya,
I would say it is going to be a prop issue here. The vengeance propeller series is basically the aluminum equivalent, just made as a steel propeller. It will add a little speed and definitely adds durability, but will perform much like the equivalent aluminum prop will. The prop will lack a bit of cupping on the trailing edge of the prop which lifts the rear, and there is some tip cupping, which helps raise the bow, but may not be enough to keep it there, which is why you get the porpoising going on...the prop loses grip at trim, bow drops...prop grabs again, pushes up, loses grip...
With the boat carrying a max hp rating of 135 in console model and weighing 1100 lbs dry, you might want to consider trying a mercury Trophy plus 4-blade prop in a 16 or 17 pitch, with the motor raised another hole or two off the transom. Raising the motor will give you the extra rpm for running the 4th blade, with the extra blade giving you that extra handling and lifting capability for the boat, allowing you to lift the bow further than what I believe you are capable of now. The prop is also vented, which means you can "dial in" your hole shot with different vent holes, but this is a tricky trade off...too large of a vent hole will give you issues for surging and holding the water at 3000 or so rpm, which can be right at that point you need it in higher seas...
If you just received the boat, see if you can go back to the dealer and try a few different props to see what works best. You might find the extra $300 or so you spend on a higher performance designed prop may pay good dividends for you..
Steve |
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Posts: 32784
Location: Rhinelander, Wisconsin | You could get the motor up a hole, you will find that transom to be over 21" I think. A 4 blade as recommended will help a ton, too. Great boat, I owned one for a couple seasons. Frequently the blame is placed on the hull, and it's always propping and rigging. Call me with questions anytime at 800.359.4416. |
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Posts: 63
Location: Maribel WI | Thanks, going after the prop first. |
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Posts: 397
| Had the same problem on my navigator with a yamaha 75. dropped one pitch size and it took care of the problem
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Posts: 63
Location: Maribel WI | Just for anyone else's benefit, going to a 17 pitch and a 4 blade prop did the trick. Thanks for the help. |
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Posts: 397
| I dropped mine to a 17 pitch as well from a 19. glad you figured it out |
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