Bennett Trim Tabs
Most trim tabs are driver-adjustable metal or composite flaps that are fixed to the transom near the bottom of the hull, essentially extending the running surface.
There are a variety of designs and materials, but all driver-adjustable models function in the same way. Generally prices range from $500 to $800 for a complete system.
Trim Tab & systems
Bennett Trim Tabs
Self-Leveling Bennett Tabs (SLT)
Small Price Tag, Big Benefits.
The durability Bennett Tabs without hydraulics needs – simply mount the two actuators and trim tabs for a smoother ride. Recommended for use on Ribs
Skiffs, and Runabouts.
- SLT6 Bennett 6″ x 8″ Tabs
- SLT10 Bennett 10″ x 10″ Tabs
Classic and Hydraulic Boat Trim Tab Systems
Hydraulics Trim Tab with Proven Reliability and Durability
Hydraulics Trim Tab will reduce pounding and eliminate porpoising, improve also safety and visibility. They are easy to service and maintenance. Recommended for use on Flats Boats, CC, DC, Trailered Boats, Cuddy Cabins,Deck Boats, Bass Boats, Sportfish, Runabouts and Ribs.
Hydraulic Bennett Trim Tab Sets with Electronic Indicator Control
Hydraulic Bennett Trim Tab Sets with Euro-Style Control
Hydraulic Bennett Trim Tab Sets without Controls
Hydraulic Bennett Trim Tab Sets with Tab Position Indicator
M80/M120 Sport Tab Systems
M80 & M120 Bennett Sport Tab System
(Model: M80) M80 Sport Tab System and with Electronic Indicator Control (Model: M80EIC)
(M120) M120 Sport Tab System and with Electronic Indicator Control (M120EIC)
(Model: M80TPI) M80 with Bennett Tab Position Indicator
(Model: M120TPI) M120 with Bennett Tab Position Indicator
Unique Space-saving design that will fit virtually any boat transom. M80 & M120 trim tabs Systems provides 30% more lift than conventional units. Recommended for use on almost every type boat, from small Flats Boats to Cruisers and Sportfish.
"BOLT" Electric Bennett Trim Tab System
Cutting edge-technology with a water tight actuator
Robust, and seal design Electric Trim Tabs for harsh marine environment, completely protected wires and seals.
available models Includes from 12″ x 9″ to 24″ x 12″ Trim Plane Assemblies
Sport Tab Systems
Performance Hydraulics Trim Tabs
Durability and Reliability with accurate and precise control.
available models from (ST9) 12″ x 9″ Tabs for boats below 21" to 12 x 16 Sport Tab System w/ EIC.
Premier Line Bennett XPT/BXT/SST Trim Tabs
Trim Tab Systems designed from single or dual SS for Luxury yachts, Sport Fishing and Boats from30 ft to 120 ft in length. Trim Tabs Systems can readily be retrofitted to any boat.
XPT1218 Model: 12″ x 18″ Trim Plane Assembly (Single actuator per tab)
XPT1520 Model: 15″ x 20″ Trim Plane Assembly (Single)
XPT1824 Model: 18″ x 24″ Trim Plane Assembly (Dual actuators per tab)
Why to use
Not every boat needs trim tabs, but just about every boat will perform better with them. Even with a well-designed hull, there are benefits aplenty, including the ability to improve hole shots, lower planing speeds, level unbalanced loads, adjust running attitudes and soften rides. And if your rig has power or design problems, tabs can be your boating salvation.
The role of the Trim Tabs
They function like the control surfaces on an airplane wing, allowing you to change the running attitude of the boat while it's on plane. Some are moved by hydraulic pressure, others by electric motors. Controls at the helm let you adjust both tabs in unison or individually.
Smoothing the seas
One of the main reasons for tabs is riding comfort. By forcing the sharper bow “entry” portion of your keel into first contact with oncoming waves, you noticeably smooth the ride. This is particularly true with boats that don't have deep-V hulls. In a head-on sea, you want to keep the bow down to help reduce pounding.
While you can improve the boat's ride considerably by trimming your outboard or drive “down” (toward the transom), this increases the depth at which the skeg and prop run, in turn reducing the efficiency of the prop, which works best when it's pushing straight ahead. Your speed at a given rpm will be reduced, as will your fuel economy. Tabs allow you to trim the outboard or drive for maximum efficiency, and then adjust the ride using the trim tabs.
Trim Tabs also are very helpful when you've loaded your rig with gear and crew. Hundreds of extra pounds can make your boat sluggish out of the hole. It may squat in the stern and ride bow high, impairing forward visibility. Again, trim tabs to the rescue. Put the tabs down, and it's like you've added a launch gear for hole shots. Tabs also can keep the boat at a level running attitude in the 3000- to 4000-rpm range, where you probably run most often.
If you have a boat that's inclined to porpoise in the midrange, a touch of tab can eliminate the rocking-horse motion. Porpoising can be dramatic in some hull/engine combinations, becoming wild enough that control is difficult at some speed and trim positions, particularly in rigs capable of running faster than 50 mph.
And, if your buddy who plays offensive line for the Oakland Raiders decides to join you for a fishing trip, you can use tabs to level out the boat instead of going down the bay with the gunwale on his side nearly submerged. You do this by lowering the tab on his side. The flow of the water against that tab exerts an upward force, and the boat levels out.
And of course, there are times when running fast in flat water where you won't need any tabs. Yet, when you'd like to run at a slow cruise from 2000 to 3000 rpm, you might need a little tab help. At this speed, just barely over the hump for most boats, the boat keeps trying to fall off plane. By dropping the tabs, you give the back of the boat a bit of added lift and can stay on plane at lower speeds.
There are a few cautions in using tabs. Too much tab forces the bow of the boat down, and can cause severe “bow steer” in a deep-V hull. The forward V, sitting deep in the water as a result of the tab position, can act as a pivot point if you hit a wave at an angle or turn the wheel slightly. It can make the boat “bow-steer” or slew mightily in the direction of your turn. If you feel any tendency of the boat to bow-steer when it hits a wave, raise the tabs until the ride becomes more civilized.
Too much tab also can drop the bow enough so that a wave rolls in over the forward deck. And when you're running fast down steep swells, using any tab at all may cause you to stuff the bow into the backside of a wave or “stick it” at the bottom of the trough.
This can result in a frightening event known as “pitch-poling,” in which the boat does an end-for-end flip and lands upside down. That's rare, but it happens every year to unwary boaters.
the spans and chords
The length of a tab front to back is known as the “chord,” and the width side to side is called the “span.” The appropriate chord for most trailer boats ranges from 8 to 12 inches.
When it comes to the span, go with the largest that will fit the transom while leaving at least an 8-inch space between the inside of each tab and the lower unit, and 3 to 4 inches to the chines on each side. The rule of thumb is to have an inch of span per tab for each foot of boat length (assuming a 9 inch chord). So, for a 20-foot boat, you want a 9x20-inch set of tabs.
If you trailer your boat, you might want an accessory known as an “automatic tab retractor,” such as those made by Bennett and Lenco. These automatically return the tabs to a full up position anytime the ignition key is shut off.
Otherwise, you may run the boat too far on the bunks with the tabs down, which could damage either the tab or the actuator.
How To Install A Set Of "Bennett Marine" Trim Tabs
Step 1. Measure at least 3 inches from the chines to give your tabs a little space should the transom bump a dock, and for outboard and inboard engines, make sure they stay at least 8 inches from the centerline of the boat so that they don't interfere with the water flow to the prop.
Step 2. Most tabs come with a backing plate. Use this as a template to mark the locations for screw holes to mount the tabs. Mount about ¼-inch above flush with the bottom. Use screws provided, or No. 10 x 1¼-inch stainless-steel screws for mounting. Drill 9?64-inch guide holes through the fiberglass skin of the transom, then countersink the holes to prevent later cracking of the fiberglass, use a drill bit or a reamer the size of the head of the screw and gently create a small divot just big enough for the screw shoulder to settle into. Fill the holes with a hardening sealer like 5200 or marine epoxy before screwing the backing plate and tab hinges into place, the sealer prevents water from getting into the core of your transom, should it be composed of plywood as many are.
Step 3. Attach the actuators to the tab with the machine screws provided, allowing the top of the actuator to remain loose for the moment. Now you're ready to set the angle of the tabs when in the “up” position, that is when they should have no affect on the boat. You do this by extending a straightedge, a stiff yardstick is fine out from the bottom of the boat with a screw in the top of the stick so that it measures ½-inch above flush to the back edge of the tab for tabs with 9-inch chord, or 5/8-inch above flush for tabs with 12-inch chord.
Step 4. Have a helper hold the planing plate in the negative angle position described in Step 3 while you mark the position of the upper mounts for the actuators on the transom. Mark the position of the screw holes, or if your tabs come with a template for this step, tape it to the transom. Drill the holes for the mounts and for the hydraulic line as indicated on the template, typically 3'16-inch holes an inch or more deep for the mounting screws, and a ½-inch hole in the center to fit hydraulic lines again countersinking each hole.
Step 5. For hydraulic tabs, install the hydraulic lines into the upper actuator mounts and tighten in place. Put a piece of masking tape over the openings of the lines so that debris can't get inside.
Step 6. Feed the hydraulic line through the transom and mount the actuator to the transom, being careful to seal the screws with a marine-grade bedding compound.
Step 7. Mount the pump and reservoir in a dry location inside the transom; trim and install the hydraulic lines, route the power/control wires to the helm and install the trim tab switch.
Step 8. Fill the reservoir with automatic transmission fluid, tighten the fill cap, then purge the system by first holding the controls in the “bow down” position for 15 seconds, then in the “bow up” position for 15 seconds. No further bleeding should be needed.
Step 9. Put the tabs in the down position and check for leaks. Make sure all wires and hoses are secured to bulkheads. Then bring tabs full up and check the fluid level, add more if necessary. That's it, you're done.
Trim tabs For speed or not
Tabs will allow you to keep the bow down at lower speeds and keep the boat stable at higher speeds. If you are considering more power down the road tabs and hydraulic steering are a must.
You don't necessarily need tabs for your current setup but they will help with low speed plaining and balance. Just like everything else buy the best ones you can afford. The sport tabs are fine now but if you ever want to go faster they won't be right for you. Because they are spring loaded one direction the water can actually suck them down at higher speeds and increase drag.
It can keep the boat planted a bit more in trimmed up full throttle rough water situations. You are still within the design limits of the hull with your current power so they aren't completely required but it sounds like for what you are trying to do they will work for you.
The only benefit would be if you needed them for low speed wakeboarding. You may be better served purchasing an Exhaust upgrade.
If your trying to tow or go 25-35mph you have to fight to keep it on plane. It will run 72mph wot just fine though. Just want more lower speed control. And will eventually like to do some motor upgrades.
Hydrofoils - Workplace experience and advice
Trim Tab Manufactures
Lectrotab.com - Standard,Aluminum Alloy, Heavy Duty Trim Tabs, Dual Actuator and Custom Tabs
Volvo Penta (http://www.volvopenta.com/)