Bennett Marine SLT-10 Trim Tabs

Zzotto21

Registered Member
State
FL
I installed my Bennett Marine trim tabs on my Triumph 170 DC, recently. I bought the SLT-10’s. Here is the good, the bad, and the ugly.



I went with the Bennett Marine “self-leveling” trim tabs. How these trim tabs work is easy: they use a spring loaded actuator. No wiring, no plumbing for hydraulics, etc. Just install them onto the transom and let them do the work. They have a pin in place to keep them up. When you want to use them, you lift up on the trim tab and remove the pin. The SLT-10’s use a spring with about 90 lbs. of force. The 6’s use a spring with about 60 lbs. of force. Once down, you can not adjust them. Water pressure, speed, weight, etc., make them “self-adjusting.” I would recommend visiting the Bennett Marine website for more information: https://bennetttrimtabs.com/product/self-leveling-tabs/



First off, I think I made a mistake when I bought the SLT-10’s. For some reason, I thought the 170 DC was 17’ 10”. I am not sure why. But it is not. It is 16’ 10”. Not quite 17’. Why is this important? Because Bennett Marine indicates that for boats 17’ to 20’, you should use the SLT-10’s and the SLT-6’s for boats up to 16’. That puts the 170 DC smack dab in the middle of their recommendations.



I contacted Bennett Marine via email and they recommended the SLT-10’s. So that is what I purchased. And that is what I installed. But, I wish I would have gone with the SLT-6’s. More on that in a little while.



What is Supplied: The package includes the trim tabs, the actuators, and all the hardware (screws, etc.) needed to install the trim tabs. You will need the recommended tools (screwdrivers, straight edge/level, drill, marine sealant, etc.)



Before I forget, I searched around the internet and learned that normal marine sealant is not what you want to use on Triumph or other “plastic” boats. It was recommended that one use a product from Sudbury: Elastomeric Marine Sealant. I found it on Amazon but I am sure you can find it elsewhere as well. It is recommended that you use a marine sealant in the installation as you will be drilling into the transom.



Installation: Installation was very easy. Especially on the Triumph’s, because of how easy it is to drill into Roplene. The stainless steel trim tabs come with a stainless steel backing plate that you use as a template to mark the holes in the transom. The trim tabs are installed as follows: the backing plate, the front plate, between which slides the trim tab. Four (4) screws secure the trim tab to the transom.



You then install the actuator to the trim tab using two (2) screws. Very easy. Once you have the actuator secured to the trim tab, you then use a straight edge or level to make sure you have the trim tab level with the bottom of the boat. Once you do that, you place the top of the actuator onto the transom and mark off where you will drill the three (3) holes that will secure the actuator to the transom.



As for the drilled holes and screws, it is recommended that you dip your screws into marine sealant before inserting the screws. I was a little nervous about drilling into the transom below the waterline so I filled the holes with marine sealant AND had marine sealant on the screws when I secured them to the transom. Better to be safe than sorry.



The entire installation process took me less than an hour, once I had all the tools I needed out and ready to go. But I also had to relocate the transducer to my Hummingbird GPS/Fish Finder, which took me a little longer than expected. More on that later, as well.



I waited 24 hours to allow the marine sealant to fully dry. Not sure if you have to do that, but why not? Can’t hurt, right? The next day, I took her out for some “sea trials.” I must say, I was VERY disappointed. Yes. VERY disappointed.



I started the trials with the trim tabs down. Remember, they are self leveling. And I was alone in the boat. The first thing I noticed was how quickly I got up on plain. The hole shot. Amazing, actually. I have a Yamaha F60 on her so she is not over-powered. But the difference in the hole shot was very noticeable.



Now for the bad: I lost about 6-8 mph top end speed. Alone, I can sometimes see 30 mph on my boat. With the drag of the SLT-10’s, the best I could do was 23 mph, but it was usually in the 22 mph range. Those trim tabs down, with all that down force, create a to of drag. So very unhappy about that.



And, I had a giant rooster tail on the starboard side of the stern. I had no idea what that was about and the trim tab is below the small swim platform/ladder. But later in the day, when I had a friend come with me, I looked off the stern and realized my transducer was way too far low in the water. I had no idea how precise you need to be when installing transducer.



But with my friend on the boat, with the tabs down, the hole shot was great. But again, the top end speed was gone and the motor sounded like it was bogging down.



Also, the bow of the boat was so far down, it was digging into the water. We were waiting for the bow to dig in and turn us abruptly.



So after the sea trials, I was not happy. I thought I could use them up, pinned, if you will, and get some benefit that way. And maybe use them down when I had 4 people on board. But losing all the speed? I was not sure if they were worth the benefits.



But, I decided to contact Bennett Marine. And I am really glad I did. I described what was happening and asked if I could purchased the springs for the SLT-6’s. I was told they do not sell just the springs but they would send me the complete SLT-6 actuators, on the Honor System – I would have to send back the 10’s when I got the 6’s installed. That worked for me. And as a result, I have to say that Bennett Marine appears to be a great company.



Swapping out the actuators was a bit tricky because of the tension of the 90 lbs springs of the 10’s. You have to unscrew the actuators from the trim tabs which then allows you to unscrew the actuator from the top bracket. You do not have to take off anything you attached to the transom, however. You simply unscrew the actuator from the top but be very careful! It is under tension. Getting the 10’s off was pretty easy, what was more difficult was screwing the 6’s onto the top of thee actuator. You have to force the spring up and screw at the same time. 60 lbs. of pressure made that somewhat difficult but it is doable.



I also relocated the transducer at the same time. I found the installation directions and did the best I could to locate the transducer in the best place possible, considering the trim tabs, the live-well intake, etc.



The result? FANTASTIC! It is like it is a different boat when considering the handling, the hole shot, etc. The Bennett Marine website indicates the following:



Features Include:

Three mounting options to easily change lift

Plane at lower speeds

Improve fuel efficiency

Eliminate porpoising and chine walking

Improve your hole shot

Reduce engine laboring and improve fuel efficiency

So far, I agree with everything they mention, but I am still experimenting.



And remember, for the 170 DC, the SLT-6’s are the way to go. I now have what I call a hybrid, as I still have the SLT-10 trim tabs but with the SLT-6 actuators. But the sea trial saw me get back 3-4 mph top end speed, I still get a much better hole shot, and the handling of the boat is much better, especially in moderate chop. I want to get more people on the boat, use them up, use them down, etc. But so far? I really think they are an improvement.



I would highly recommend them for your Triumph 170 DC. But again, go with the SLT-6’s. I can’t speak about other Triumph bots but from what I hear, everyone thinks the improved hole shot, handling, etc., is well worth the expense and the no hassle DIY installation of “self-leveling” trim tabs.









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