cobra plate
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Outta Here
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If you run in open water, sooner or later you'll want to add trim tabs. IMO, Cobra Plates (I assume that is a sheet of metal bolted to the cavitation plate?) and Doelfins, etc. do not replace tabs.
No they don't, but they are significantly cheaper. Before I added the two plates (I have twins), the Diamond was stern heavy and I couldn't get the bow down to get a decent ride in the chop. I'd tuck the motors all the way into the transom and put the tabs all the way down, and about the only thing I accomplished was to significantly increase my fuel consumption. I believe the extra weight of the 4-strokes on the bracket pull the center of gravity to the rear, making the 12x12 tabs near worthless.
After I added the plates, she was a different boat. The motors are now trimmed closer to neutral (prop shaft approximately parallel to the keel at the transom), and the tabs are much more sensitive. A bit of tab makes a difference. I lost about 1 mph at WOT, but gained a much better ride in the chop, much less fuel consumption, and can stay on plane at about 14 mph.
You could do the same with tabs, but for a lot more money.
After I added the plates, she was a different boat. The motors are now trimmed closer to neutral (prop shaft approximately parallel to the keel at the transom), and the tabs are much more sensitive. A bit of tab makes a difference. I lost about 1 mph at WOT, but gained a much better ride in the chop, much less fuel consumption, and can stay on plane at about 14 mph.
You could do the same with tabs, but for a lot more money.
Forgot to mention...there is always a downside. One of the sales reps at my dealer told me that drilling holes in the anti-ventilation plate could void the warranty on the lower unit...if Yamaha wanted to make an issue of it.
In my opinion, drilling the holes in the plate does not touch the gear case, and actually helps the motor because it is not tucked into the transom all the time, laboring to push the bow down. When I tucked the motors in, I lost about 400 rpm, had to increase the throttle setting to maintain the same speed, and increased fuel consumption. The motors were laboring to keep me at the same speed. So...I think I did them a favor...but that is my opinion.
In my opinion, drilling the holes in the plate does not touch the gear case, and actually helps the motor because it is not tucked into the transom all the time, laboring to push the bow down. When I tucked the motors in, I lost about 400 rpm, had to increase the throttle setting to maintain the same speed, and increased fuel consumption. The motors were laboring to keep me at the same speed. So...I think I did them a favor...but that is my opinion.
jeffnick
Well-known member
I've got a Cobra (I think it's a Cobra) I used on my 2000 115 Evinrude. It's a cosmetic train wreck but there's no nicks or bends in the aluminum. I've also got one of those flip down things for trolling from a '96 115 Merc that works as a hydrofoil when it's up.
I'm on the road for a couple weeks (road? Ha, we're going to Hawaii) but if you're interested in the Cobra? for 22.50 + shipping, (or the trolling thingy) we can work out details when I get back.
I'm on the road for a couple weeks (road? Ha, we're going to Hawaii) but if you're interested in the Cobra? for 22.50 + shipping, (or the trolling thingy) we can work out details when I get back.
If you have the $$, go with tabs. My plates were the quick/cheap route.
If I ever repower (probably with F-150s or 150 e-TECS), I'll upgrade the tabs and drop the plates.
If I ever repower (probably with F-150s or 150 e-TECS), I'll upgrade the tabs and drop the plates.
