Slow boat mercury 60 wrong prop?

[desertratz]

I have a 16' tracker deep v with a 60hp mercury 4 stroke efi 1.83:1 gear ratio. The prop is a 10.6" with a 12 pitch 4 blade. Boat runs max speed 19 mph. My goal is max speed is this the wrong prop? This is the slowest boat I've ever owned.

 

[justinshreve1986]

this is the best prop i have found so far Mercury Spitfire 4-Blade Aluminum 10.1 x 14P 48-8M8026635 and you should hit about 35 mph at about 5500 to 6000 rpms

 

[achris]

I have a 16' tracker deep v with a 60hp mercury 4 stroke efi 1.83:1 gear ratio. The prop is a 10.6" with a 12 pitch 4 blade. Boat runs max speed 19 mph. My goal is max speed is this the wrong prop? This is the slowest boat I've ever owned.

Based on that information, you should be running at about 30knots. You have the right prop, but if all you're getting is 16 knots, there's something wrong with the engine (or the boat is still full of water!). What RPM are you getting at full throttle? Has the boat ever made 30 knots? Is this a boat you have just bought, and was it running right when you test drove it? Has work recently been done on the engine?

Chris.......

 

[WesNewell]

There are many 16' trackers weighing from 700-1200#. Without knowing which model you have, no one can give you a correct answer as proper prop could vary from 10-15P. Either provide more info or use the mercury prop finder where it will ask for the info.

 

[jimmbo]

Either Boat has Problems(Heavy from trapped Water. or a Hook, or badly overloaded), or the Engine isn't up to snuff.

What WOT RPM are you getting with the current Prop?

 

[desertratz]

The model of the Tracker is a v16 targa walk through 2004. i bought this boat recently this is the second time ive had it on the water for short trips. It is not overloaded just 2 people. unfortunatley the tach does not work so i dont know what im spinning, but mechanically it is wot. Engine runs great I fully serviced it. Mercury prop finder recommends the prop on it as one of the recommendations.

 

[ahicks]

When the goal is max speed, a 4 blade prop is never going to be a better solution than a 3 blade. The extra blade is extra drag, and way more about generating (low speed) thrust and holding the boat on plane at lower speeds.

If you want to go fast, you want a 3 blade. If you want to know if you have the right prop you need a tach.

My experience, based on a 16' alum. side console Sea Nymph and Honda 50's, is a 14" prop will have you well over 30mph when lightly loaded.

 

[WesNewell]

That's a 1300# boat. 12P is the right pitch for it. With everything right, you can expect a max speed of ~30 mph with a 60 hp 4s turning about 5750 rpm. The boat is rated for a 90hp, so you are under powered quite a bit. I've seen many trackers with the engine mounted too low, but I doubt that would amount to that much speed loss. Usually only accounts for about a 10% loss in speed. If you can't get at least 25 mph, you've got more problems. Things to check: engine and mount height, hull clean and straight, waterlogged boat. Good luck.

 

[desertratz]

I pulled the whole floor out last weekend to fix a hole in the hull there was no water and the foam did not look water logged. Not sure what difference it makes but it has a hydrofoil on the lower unit. Could trim setting slow it down that much? i might try to play with different trim angles this weekend as well as fix the tach issue to get a better idea of whats going on.

 

[WesNewell]

Remove the whale tail. All they do is add drag and try to make up for an improperly mounted engine. They are more than worthless. On a properly mounted engine, they shouldn't even be beneath the water line on plane. On a deep V hull you want the av plate above the bottom of the V a little. On plane, the av plate should be above the water line, not under it..

 

[desertratz]

I will remove the hydrofoil tomorrow. UPdate. i fixed the tach it was a burnt out voltage regulator. i also noticed that the motor was lowered. It was lowered 2 bolt holes lower than factory why i have no idea. Im going to go run it tomorrow and see what rpms its turning at wot and update from there.

 

[achris]

Lowered 2 holes, then a foil... :facepalm:

 

[desertratz]

ok, so i took the advice and removed the foil last night ran it today it actually got on plane its turning 5400 rpm at wot at 28 mph. alot better but im wondering if it would be possible to get more top speed out of it, different prop?

 

[JimS123]

Your RPMs are slightly low. Probably because you are down 2 holes. Move the engine up so the AV plate is "slightly" above the bottom of the boat.

You should be turning 5500-6000 rpm, preferably close to the top end.

When you get that optimized, put the foil back on and give it a try.

If you're serious about performance, it might take a couple tries at different hole heights.

My guess is that you should come in at about 30 mph and the foil will improve your hole shot without affecting your top speed. The caveat is that the AV plate can't be under water at plane.

 

[achris]

Your RPMs are slightly low. Probably because you are down 2 holes. Move the engine up so the AV plate is "slightly" above the bottom of the boat.

You should be turning 5500-6000 rpm, preferably close to the top end.

When you get that optimized, put the foil back on and give it a try.

If you're serious about performance, it might take a couple tries at different hole heights.

My guess is that you should come in at about 30 mph and the foil will improve your hole shot without affecting your top speed. The caveat is that the AV plate can't be under water at plane.

Agree with all of the above, and will add...

ONLY put foils on if your anti-cav plate is AT LEAST 1" ABOVE the bottom of the hull. The original design of those foils was to improve acceleration and give the boat a lower planing speed. Once the boat is planing, they are supposed to be out of the water.

Marketing departments decided to 'neglect' that vital piece of information on the packaging, because it would mean they would have sold about 90% less of them. Standard installation height engines DO NOT need foils.

Chris.........

 

[desertratz]

cav plate is a little lower than bottom of boat

 

[achris]

Yep, I'd be putting it up one hole, then see how it goes. Look over the back while it's planing (take someone with you to drive!) and if you can't see the AC plate out of the water, raise it one more hole.

Chris......

 

[JimS123]

Yup, one hole at a time.

Also, it looks like at full inward trim the tail end of the AV plate is angled downward. You would do better if the plate were parallel with the bottom of the boat. So, when you are testing, trim up a bit.

 

[WesNewell]

The advantages of having the engine mounted high is less drag and more speed and fuel efficiency. The disadvantage is prop blowout in sharp turns at speed I consider that a small disadvantage since I run straight 99.9% of the time . Unless you are concerned with that, I'd move it up to the middle holes to start since you have a pretty deep V hull comparably. With that hull I'd want the av plate at least to the middle of the drain plug hole and then go from there either up or down if needed.

 

[desertratz]

strangely it looks like this is how they come from the factory and someone had messed with this one already. i found a picture online that shows the engine as low as mine factory. i raised it 2 holes and measured the plate at about 1 inch above the bottom of the boat. at the lake yesterday the plate is below the water when it is running at speed. the plate now sits about center of the drain hole. i will give it a try and post back. i just dont like how the engine bracket is no longer resting on the transom.