Trim Tabs or Hydrofoils for 170 BASS?

[Steve762us]

Sounds like hydrofoils or tabs will help out...I'm a newb to outboard propulsion, so I'm listening to everyone.

One point that the "tab school" makes is that the tabs provide lift from two points, at the outer edges of the transom---vs. the hydrofoil, that provides lift from the motor (single central lift point). The tab folks say this provides a less stable lift.

What do you folks think?

[SWAMPTHANG]

I have the Naticus trim tabs on my 170cc and a SE-sport 300 hydrofoil. The trim tabs were on the boat when I bought it. I added the hydrofoil after noticing the boat seemed to skip when making sharp turns at speed. I had adjusted the trim tabs before I installed the hydrofoil and improved it's handling but, could not get the stable feeling I was looking for in the turns. I should note that my last boat was a 16' bass boat with a 135 Evinrude you could make a 50+ mph turn with it without slowing down. The two boats are totally different on the way they are designed and handle. The hydrofoil with the trim tabs seem to be a great combination as I can now take a turn close to full speed without having to play with my trim as much. I am quite pleased with the results. We use our boat for tubing and for fishing so, the extra stability has given me peace of mind. We live on the Northeast Cape Fear River where there are a lot of tight turns with no room for chine walk. I look at the adding of the trim tabs and hydrofoil as compared to tweaking your car or truck with after market parts. You add the parts to improve on handling, power or cosmetic reasons. The add ons to my boat have not only improved it's handling but, also it's fuel range. We can tube for a solid 3-3.5 hrs and only burn 5 gals of fuel. That is extremely impressive to me. My last boat would have burned 18-20 gals doing the same thing. The outboard I currently have is the DF-70 Suzuki 4 stroke with ss prop. This is by far my favorite boat as I can play all day, fish in the shallows, fish offshore without spending a fortune in fuel and do it all from the same boat. No complaints here!!!

[Troll]

I started this thread some time ago and have now had considerable time on my 170 bass with the Nautacus Trim Tabs.

When I am on a lake at an elevation under 1,000 feet, and use my 17 pitch prop, I have no problem getting up to plane in quick order. Handling is great, but when trolling, there is still a little wondering from left to right and right to left. At this elevation I can have a full tank of gas and a full live well and passengers.

When I am at my usual lake that is at 5,300 feet elevation, it is a different story. At this elevation I switch the prop to a 15 pitch. If I have a full tank of gas and or the live well full of water, getting on plane can still be a bit of a problem. Usually if there are only two of us in the boat, we can make it to plane, but it does take about 100 yards. With a third passenger, it probalby won't get on plane without someone walking forward. However, once on plane at this elevation, it performs well.

Before the trim tabs, I used to drive it WOT to keep it on plane. Now, I drive it at about 4,500 rpm with almost the same speed, but with big gas savings. My motor is a 4S Suzuki 70 hp.

While the 4 stoke engines offer great fuel economy compared to most 2 strokes, they don't seem to have the same start up torque and they are usually heavier when compared to the same horse power 2S engines.

I like the idea of installing both trim tabs and a hydrofoil to the motor, but I have elected not to drill holes in my motor.

All in all, I am still pleased with the Nauticus Trim Tabs, but I would like to know if the Nauticus Trim Tabs for the next size of boat would better fit my needs.

[SWAMPTHANG]

You may need to talk to your Suzuki dealer about running in the higher elevation. The higher elevation causes engines to usually run a lot leaner. I would talk with a Suzuki tech. to see if anything needs to be adjusted or swapped out for running at the higher elevation. You may not be getting all the fuel you need to create efficient power. Most efi's have corrected this problem since they are computer controlled but, I have heard of cases where the controller had to be swapped out to deliver the extra fuel the engine needed for running at higher elevations. I would check with Suzuki to see if this could be the case also, how high or low is your engine mounted to your transom? I believe mine is mounted on the top hole. I hope this helps I know how frustating it can be to have your toys not perform the way you expect them to.

[HIGH&DRY]

Altitude performance.
At high elevations our engines are getting less air, so they need less fuel to maintain the proper air/fuel ratio. Often with a carburetor gas engine you would go down main jet size for every 1750 to 2000 feet of elevation you go up .
Generally high elevation gasoline is less dense to compensate for less available air going into the engine and to aid starting.
Cold air is dense air and dense air requires bigger jets, but this would be very much colder air than most boaters would be comfortable in.
Generally you figure about 3% power loss for every 1000 foot gain in altitude with a gasoline engine!
Diesel engines may be poorer performers, that is why turbo is popular at high altitude!
Sea level is good for very many reasons!
HIGH&DRY

[Troll]

I agree that a 70 HP engine will have about 60 HP at 5,000 feet elevation. To compensate, I switch to a 15 pitch prop, as opposed to the 17 pitch and at WOT I do get my desired max RPM's of 5400. I did check with my dealer and he told me that the Suzuki 4S 70 HP motor had an automatic fuel compensation for altitude. It was his suggestion that I also use a lower pitch prop at higher elevations.

The 170 bass is no longer in production. However, if you put 4 storage compartments (one with the battery) behind the driver and passenger along with a 20 gal fuel tank and a 10 - 15 gal live well, there is a lot of weight at the rear of the boat. I also have a 4 HP kicker motor and that must add another 40 pounds or so.

All in all, there is a lot of weight the rear half of the this boat, with virtually none in the front half. This causes the bow to just naturally rise. Look at the picture of me in the boat before the kicker motor was installed and with no water in the live well.

Perhaps this design is the reason that Triumph quit making the 170 bass.