Home Forums Fishing Freshwater Trim Tabs/Smart Tabs?

I have a brand new Smokercracft 161 XL equipped with a 60HP Mercury 4 Stroke.

With three adults in this boat it will not plane out, it actually points at the sky. The max rating for this boat is 75HP.

My dealer and Smokercraft both claim their is nothing wrong and they both suggest I install a set of trim tabs or Smart tabs.

My question, with these tabs installed can you still install a small trolling/kicker motor?
I am a walleye fisherman and backtroller. I would like to add a 6hp kicker to this boat, but not sure if I can with these plates hanging off the back?

My POS boat.
http://www.smokercraft.com/showroom/fishing-boats/pro-angler/161-xl

There is a lot involved in this topic. I'm far from the guy to know the answer, but having had a few boats I can tell you that the depth adjustment of the motor on your transom may be the easiest fix, or the type of prop.

Keep the motor lowered until near full speed then start lifting it a little bit at a time until the boat levels out. Once you hear the prop cavitate click it down once. I assume you have an electric motor tilt button on a motor that big.

Trim tabs will likely be in the way of the trolling motor. Unless it's electric or you have an extension mount.

The prop pitch and motor depth is critical to proper overall function. I went thru this myself a couple boats ago.

An alternative to trim tabs is a motor mounted Doel fin or hdydrafoil. I had a Stingray fin on my 18' Klamath and it definitely got out of the hole flatter, on step quicker, and improved the handling in rough water. I tested the boat with it installed and then removed and went back on and stayed there for good.

A Dole fin will help but it's not going to make up for a lack of thrust if the engine is bogging down. If your boat won't get on step will only three people on board then something is wrong and the prop is a very likely suspect.

Did the dealer or Smokercraft mention the prop or suggest trying a different one?

What rpm does the engine run at when it is on step?

Does it run at the max rpm the motor is rated for?

If it doesn't achieve max rpm you'll lose both top end speed and power.

I tried four different props on my boat/motor. A 13" pitch, 15", 17", and finally settled on a custom 14" pitch that I cupped. It was the perfect prop for both speed and carrying a heavy load. FWIW, I had 40hp Evinrude 2 stroke on it.

And like JJ mentioned ... "The prop pitch and motor depth is critical to proper overall function."

Here's some really good info on boat propellers.

http://www.mercurymarine.com/propellers/

One thing I'd suggest is see if your dealer will loan you a prop, to try out, that's one step lower in pitch.

By "Motor Depth" do you mean having the trim all the way down or do you mean the position the motor is bolted to the transom?

Smokercraft, Mercury and my POS Dealer all say this is the correct prop. It is a 10.38 x 12.

I have visited a few Prop calculator sites and their recommendations are all over the place.

This one seems to be the most informative and thorough, but I duno.

http://turningpointpropellers.com/

These guys say I should run a 12 x 8-9-10.5.

The RMP of this motor is 6000. With three people it points at the sky and will not get over 4000.

I am running this boat with the motor trimmed all the way down and the trim stops on the motor are at their lowest point.

Thanks for the help.

Mounting height is what I was referring to and the dealer should have it set correctly but ... ?

Just to clear things up. Does the motor reach 6000 rpm at full throttle, on step, with a light load or is that the specified max or both?

I gotta add this. When you start looking at different brands of props, different styles, 3 or 4 blade, and different diameters it's tough to compare apples to apples. That's probably why the numbers are all over the place.

Performance changes when you compare props with a given pitch but a different diameter ... and a different style, blades, etc.

The boat set up with you and gear will require a different set up then three guys and gear

It's a compromise with a light boat to make it proper for every situation. My current boat is perfect with my wife and son.

But two other guys in the boat and it will lean to the heavy side. I could adjust it to work with this load but then it would be off with a lighter load.

It's never perfect unless you add adjustable trim tabs. Which are a hella expense on a boat that size.

How many RPM`s can you turn with a full load? With a four stroke you need to be able to turn between 5500 and 6000rpm`s at wide open throttle or you will have a problem planing.Anything under 5500 requires a lower pitch prop.Rule of thumb is 300rpm per inch of pitch but it really depends on hull style and load.

Full load is only what I have done so far.

That is myself 185lbs, My buddy 210lbs and his girlfriend 160lbs, with a full tank of gas 20 Gal.

With this load it points at the sky and will barely get 4 grand.

My buddy (210lbs) hand to sit on the bow mount trolling motor to get the nose down, his girl friend had to sit on the floor beside him.

Whatever pitch prop you have you need to go down at least four inches of pitch possibly six inches.More if going to a four blade from a three blade. You have to get those rpm`s up or it will never plane correctly.Also check the height of your motor setting.Your anti-cavitation plate should be level to no more than two inches above the bottom of your hull.When trimmed all the way down.

will do thanks.

JJ,

I respectfully disagree ... at least in part.

Yes, there are compromises to made but a 16' aluminum boat with a 60 hp motor should be able to carry three people and get on step with no problem.

I don't believe trim tabs are the only solution either. The right prop and a hydrafoil should correct the problem of getting on step with a heavy load. I'm going out on limb by saying that since I've never even seen a Smokercracft 161 XL but based on my experiences it should work.

Whether or not a prop change is needed depends on what rpm it's running at WOT on plane. That's also an indicator if the motor is making 60 hp. Another factor in deciding if a prop change is necessary is how fast it gets on step with a light load.

Down four to six inches of pitch or more?

No way. How can you guess without knowing what rpm it's running at WOT on plane?

And ... The OP hasn't even tried to get it on step with light load.

How many times have you had this boat in the water?

You've never tested it with just yourself in the boat?

Has it ever been on plane?

Here's my last bit of advice ...

Take the boat to lake and see if it will get on step with just you in the boat. If doesn't ...

Take it back to the dealer and tell him to fix the motor and forget about props and trim tabs.

Good luck.

Not trying to step on anybodies toes but this is what I do for a living I have propped more than twenty thousand boats in the years I have been doing this.There may very well be something wrong with the motor.But until the Op can get the rpms up where they belong the boat will never perform correctly.Now that may mean two different props for different tasks.Sometimes it works out that way.I always recommend taking the boat out with your normal load and propping it for that load.On some boats a hydrofoil can be detrimental to the handling or even dangerous in a few cases.And it is always hard on the anti cavitation plates.I weld dozens up each year from the extra strain.

Well ...

I'm no expert on boat props but reducing the pitch by 4 to 6 inches doesn't sound right to me. I have difficulty believing that a factory prop, if it is correct, is that far off and especially since it's on a 16' aluminium boat. The standard prop may not be perfect but it should at least be in the ballpark.

mch has given you good advise. I have ran many bass & fishing boats & the set-up is incorrect. This is something the dealer should correct. Probably a 3-4 blade SS prop will solve your problem after dealer makes adjustments. Even with an aluminum prop you should be able to plane with 3 anglers. I have a 14' Smoker Craft that I use to fish ponds & small rivers & while its a far cheaper boat than my Ranger is quite serviceable. I have added a Whales Tail to the last several bass boats I ran, but for a different reason. If the lake is really wind blown this helps me keep the bow high to ride over the swells. Also helps a bit on the hole shot.

You have received excellent advice. Sounds like you need to reprop.

I would like to talk about the trim tabs. I installed Bennett trim tabs on my Deep V center console 1910 trophy bayliner 25 years ago. Only thing that wore out was the joystick control which I replaced this year.

I feel the trim tabs were a major improvement in a boat's performance. They will get you on plane very easily even without getting hard on the throttle. I frequently will ease the throttle open saving gas and the work the engine would otherwise do.

You can stay on plane a much slower speeds which reduces the beating you sometimes get when knifing into big waves. It also brings the bow down so you cut through a wave instead of getting hammered.

When I was at Lake Powell I cruised looking for boiling stripers. After catching a few I would never adjust the trim on the motor, bury the trim tabs and get up on plane to the same RPM and cruise again.

If the boat lists while on plane due to angling into waves the attitude can be leveled out or even increased so the gunwale on that side is higher to prevent waves from splashing occupants.
I would never own a boat without them.

I would call Bennett Marine to see if your boat has enough room to put them to use.

I had it in the water Once. I took delivery of it May 17 2014.

I put it in the water on May 27 2014. I launched to boat and took it across the lake by Myself to the Resort we were staying at.

It planed out with just me in it, but it took almost 10 seconds and porpoised badly. I forgot to check the RPMs.

With three people it would not plane at all. At their request I brought it back to the dealer. It has been sitting there since May 30th.

Here is the exact boat, it is a Package set up by Smokercraft.

http://www.smokercraft.com/showroom/fishing-boats/pro-angler/161-xl

I know this link says 90hp, but my boat says 75HP. According to Smokercraft Customer service, they changed/increased the flotation foam to get a 90HP approval in Feb 2014 mine was manufactured before that.

The Prop on this motor is a 10.38 x 12 Aluminum.

The prop calculator here
http://turningpointpropellers.com/
recommends a 12.5 x 8 for water sports and heavy loads, a 10.875 X 11 for cruising and a 10.5 X 11 Stainless.

Does this sound correct.

10.875 X 11 is only one pitch down and a half inch larger in diameter?

Thanks.

Steve,
I also have a 60hp Merc 4 stroke. Mine is on a 17ft.
Lowe bass/john boat.
The prop is 10 3/8"x16 pitch and its a little slow to plain with two people, gas... the max rpm is 5200, good top speed though.
I have a 10 3/8"x12 pitch I put on and will try out the next few days, I will let you know. I am hoping for faster hole shot and 5700rpm at WOT.
My boat has a shallower V and probably weighs a little less than yours, but by no means feels under powered. Oh and I am at 3400ft elevation.
This is my first experience with a four stroke outboard and so far I LOVE it! fuel mileage, quiet, smooth...
I was told slower hole shot... over the two strokes, so it's just as I expected, the good definitely outweighs the bad.
I suspect if you can get yours sorted out you will love it.

Thanks, hole shot is not an issue for me, mine will just simply point at the moon.

Now that we have some info to go on that's a start.

Since the dealer asked you to bring the boat in that's a clue that something is not right and it's not unlikely that something is wrong with the motor. It may not be producing 60 hp.

I wouldn't contemplate any changes until the dealer finishes inspecting and completing whatever repairs are needed. After that take it out on a lake, check the rpms on step, and you'll have a baseline to determine if a prop change is necessary and how much of change is needed ... if any.

A 60hp motor on 16' boat is like peas and carrots. They go together very well and the factory prop, if it's the correct one, should be in the ballpark. If a change is needed it should be relatively minor. My disagreement with MCH was his suggestion that "at least four inches of pitch possibly six inches" are needed. A six inch reduction in pitch is a 50% reduction from what you have now. That's an extremely radical change and IMO is way beyond what might be needed. MCH might have jumped the gun with his first suggestion but I have no doubt, that with the right info, that he could recommend the optimal prop.

The props you mentioned go from eight inches of pitch to twelve. That covers the spectrum of everything from pontoon boats, which are very heavy, to a 14' runabout which is very light. IMHO, your boat would fall in middle and lean slightly towards the lighter end. The small change of only one pitch down and a half inch larger in diameter is in the ballpark and typical.

With that said until you measure the rpm on step it would be difficult for someone to recommend the optimal propeller. The exception would be if someone has intimate knowledge of the same boat/motor combo and Smokercraft, Mercury, and your POS dealer have all stated the prop is correct for your application. It may not be the optimal prop but you shouldn't have to vary too far, if needed, from what it is.


I lived in Anchorage for 14 years and a very popular style of boat was a 16' to 18' aluminum hull with a 35 hp motor. The reason for the 35 was the lower Kenai was restricted to 35 hp or less. I'm very familiar with boats of this type and what they're capable of. I owned two Kenai River legal boats and many of my friends had Kenai legal boats.

I can assure you that a 60 hp motor on 16' aluminum boat is more than enough to carry three people, 20 gallons of fuel, 25 gallons of water in the live well, and get on step. A typical Kenai river guide boat with a 35 would get on step with five or six people on board with no problem.

My suggestion for a hydrafoil was based on my experience with these types of boats. As long as they're properly mounted and you don't run over logs or hit submerged objects they won't all by themselves damage the cavitation plate. I've never heard anyone suggest a hydrafoil on relatively low hp boat that operates at modest speeds is any way dangerous. Could be, but I'm not aware of it.

I've had nothing but positive experiences with hyarafoils on smallish boats. It's a low cost alternative to trim tabs and it will the keep the bow down when coming out of the hole. Worst case, if you feel that it doesn't perform like you want, take it off, and go from there. You'll have a few holes drilled in the cavition plate but that's no big deal. Trim tabs might be your cookie. I'd even suggest asking Smokercraft about their recommendations to cure the bow up on take off.

Like I said I'm not an expert on boat propellers but my first career was in aviation and in particular overhauling aircraft propellers. The last six years I served as the Chief Inspector for an FAA Certified Aircraft Propeller Repair Station. Granted, boat props and aircraft props are two entirely different animals but the basics still apply and I have very good understanding of what pitch is.

Once you get things squared away with the dealer and if you feel a prop change is warranted then contact an expert. MCH seems like a good man and I'm sure he'd be able to help you out.

He posted his contact info in his first post on the fire and offered to help anyone with prop questions. He's at The Prop Shop in Knoxville 865-693-0071.


That's ^^^ a long post.

Hopefully there's some good advice in there somewhere.

You are much more patient than me! If I just took delivery of a new boat and had your issues, and they had it back in the shop for a month, I'd be all over them like a bad rash.
Obviously the boat has more than enough power (running correctly) with the load you have in it. I'd be leaning on the dealership hard to get the boat properly set up and back in the water.

The service Manger seems very nice and very concerned, but as time goes by it is clear he is all mouth and no action.

He has promised me several times he will take my boat out (after work ) with friends and family. Saturday the 28th was his last promise. I will have to wait till Monday to find out if he took it out and what he found. My guess is he didn't touch it and it is still sitting there gathering dust.

I even offered to pay extra for a bigger 75hp motor and a 6hp Kicker. No sales person (the owner) has called me back on that offer either.

I did call the factory, told them the problem, they requested the Dealer take it for a ride and if they find it has issues that I described, they will come pick it up and fix the problem. That should pretty much put this boat out of commission for the rest of the summer. Especially if I can't get the dealer to put the damn thing in the water.

I think their plan id to just keep making empty promises until I get fed up and tell them to F-off and I will come pick it up and deal with it myself.

If anyone is interested in the Dealer, they are in Minong WI.

Please- update- what did you learn? Sounds really weird.