Planing attachment on cavitation plate - are trim planes better

[seafever]

Well looking at the wish book, which is a winter pastime around here. I am wondering if, considering the cost and work involved, how cavitaion plate planer attachments compare to trim tabs like the bennett setup. Or can both be used at once?
I have an old Bennett system but not all the parts, a planer plate would be cheaper, but do they work? Does anyone have an old style Bennett controller in the 1970s style? How many $$?
Thanks

 

[steelespike]

Re: Planing attachment on cavitation plate - are trim planes better

A hydofoil like the doelfin, usually work well.And I have good personal experience with a Doelfin on an outboard and an I/O.
Conditions need to be right for them to work right and even at best they usually steel a little speed.
I do feel that something like smart tabs is a better choice.They will improve hole shot,stay on plane easier, and will reduce no wake speed wander some boats struggle with.All theses devices need to be applied conservatively to get the best results and avoid complications of too aggressively applied tabs.

 

[Georgesalmon]

Re: Planing attachment on cavitation plate - are trim planes better

Fix your bennet tabs. There is a guy on here that can tell you everything you need to know about finding parts. He'll show up I imagine for sure after the holidays.

 

[Chris1956]

Re: Planing attachment on cavitation plate - are trim planes better

Trim tabs IMHO are much better than whale tails. Hydraulic Trim Tabs are the best, by far. What kind of boat/motor combo so you have.

 

[kfa4303]

Re: Planing attachment on cavitation plate - are trim planes better

+1. For the most part "whale tails"/"dole fins" are a bit of a gimmick. After all, there's a reason manufacturers don't include them in their stock set ups. In theory, they're designed to prevent ventilation (air from above the waterline getting caught in the prop), not cavitation (air boiling on the surface of the prop, below the waterline). Smart/Trim tabs are by far a better bet with Lenco and Bennet being the brand leaders. The tabs will also add a bit of value to the boat and you won't have to drill any holes in the motor, which could void the warranty.

 

[metriccrescentwrench]

Re: Planing attachment on cavitation plate - are trim planes better

In theory, they're designed to prevent ventilation (air from above the waterline getting caught in the prop), not cavitation (air boiling on the surface of the prop, below the waterline).

NO. Doel fins, whale tales, whatever you want to call 'em add lift, especially when the engine is trimmed down, which will help you get on plane quicker and to plane at a lower speed.

The tabs will also add a bit of value to the boat and you won't have to drill any holes in the motor, which could void the warranty.

I'd argue that the advantage of fins is that you don't have to drill holes in the transom and risk a rotten transom down the road. I'll concede that trim tabs are more versatile than fins, and likely do a better overall job. I'll also concede that if properly installed and sealed they shouldn't cause a problem, but on smaller boats where tabs are overkill or prohibitively expensive (compared to what the boat's worth) fins usually work.

 

[boobie]

Re: Planing attachment on cavitation plate - are trim planes better

From past experience have to agree with the above +1....

 

[wrench 3]

Re: Planing attachment on cavitation plate - are trim planes better

The whale tails work well to get you up on plain faster.(I've had a couple of them) Trim tabs have the advantage of allowing you to adjust your trim from side to side, to compensate for uneven weight distribution, wind, etc.
If you can't find a controller you should be able to use a couple of momentary contact toggle switches. I could work you up a wiring schematic if it becomes necessary.

 

[limitout]

Re: Planing attachment on cavitation plate - are trim planes better

having used both I would say adjust the load in your boat to avoid needing or using either, the whale tail you drill holes in your motor which attracts corrosion at that point and if you switch to a different brand it may need new holes in different locations. tabs drill holes in the transom that can leak to let water in or rot your transom so both are not good.

if you HAD TO use one I would drill the motor since you will use more then one motor during your boats life but hopefully only one transom is all you ever need.

the ride is about the same for getting onto a plane but after you are on plane the tabs control porpoising and also give you a more stable flat ride especially in cross waves coming in at an angle where the tail is mainly just going to control porpoising. plus the tail puts all the extra strain from the tail onto your power trim piston where the tabs transfer that extra stress to the transom that is a lot better suited to handle it.

again, adjust your motor height or trim and shift your weight loads or change your prop to solve your issues but IMHO tabs and tails are NOT the solution to the problem but only a jerry rig to solve it. if you have a very large heavy boat then that's what tabs were made and needed for but for the most part IMO most boats with tabs installed could have solved the handling issues in other ways.

 

[tazrig]

Re: Planing attachment on cavitation plate - are trim planes better

Whale tales will give you additional lift in the stern but don't have the ability to keep you boat balanced port to starboard like trim tabs do. In all but the smallest of applications trim tabs are preferable, just a whole lot more expensive.

 

[seafever]

Re: Planing attachment on cavitation plate - are trim planes better

Trim tabs IMHO are much better than whale tails. Hydraulic Trim Tabs are the best, by far. What kind of boat/motor combo so you have.

the boat is a 1974 Silverline Antigua 18T with 188 hp mercruiser v-8 she is 18 ft long beam of 88 inch and 40 inches deep, that 302 V-8 can really gobble fuel, I want a slower, flatter plane at lower RPM

 

[seafever]

Re: Planing attachment on cavitation plate - are trim planes better

I Think I have the wiring doped out ( :laugh: ) Looks like a couple of DPDT Mom-on -off- Mom-on will do it, just have to be sure they will carry the fused 20 amp supply.

The whale tails work well to get you up on plain faster.(I've had a couple of them) Trim tabs have the advantage of allowing you to adjust your trim from side to side, to compensate for uneven weight distribution, wind, etc.
If you can't find a controller you should be able to use a couple of momentary contact toggle switches. I could work you up a wiring schematic if it becomes necessary.

 

[Chris1956]

Re: Planing attachment on cavitation plate - are trim planes better

Only hydraulic trim tabs will allow you to lower your minimum planning speed. Put the tabs all the way down, and back off the throttle.

 

[kfa4303]

Re: Planing attachment on cavitation plate - are trim planes better

Again, if "whale tales" worked manufacturers would install them, but they don't, so they don't. After all, the anti-vent plate the attach to should actually be breaking the surface of the water when on plane which makes the tale useless. If you find that you "need" one, then your either under powered, or you need to shift your load. You will NEVER see a professional in any genre using them, whereas trim tabs/smart tabs are quite useful and popular (someone please show me otherwise)(don't confuse a compression plate for an dole fin). Not to mention the fact that in my neck of the woods having that big ol' contraption hanging off the motor is going to do little more than create drag and collect miles of river and sea grass, which will impair performance and fuel consumption, particularly in the miles and miles of no wake/manatee zones. This is why trim tabs are a much better option. They let you get and stay on plane at much lower speeds and with much more control of the load.
Transoms are designed to be drilled into. Motors are not. Many modern boats don't have a splinter of wood in them, so rot isn't an issue and if you install the tabs correctly it won't be an issue with a wooden transom either (5200 is your friend). I'll repeat this again: Drilling holes in your motor WILL VOID THE WARRANTY!!!! Don't believe me, at least call the dealership before you do so. If that's not an issue, fine, but don't suggest that it doesn't matter one way or the other. It does.
I'll agree that the temptation for a quick/cheap/easy fix is strong, but that alone should tell you it's a bit of a gimmick.
Caveat Emptor!

Here's a pic of a Jackplate/Trim tab combo done the right way. Between the two, you can hop up on plane in a matter of seconds and run WOT all day in less than 12" of water. Notice the distinct lack of a whale tail I'm just sayin'.

 

[JimS123]

Re: Planing attachment on cavitation plate - are trim planes better

Again, if "whale tales" worked manufacturers would install them, but they don't, so they don't. View attachment 220075

But they DO work. 1.45 million satisfied customers are proof of that.

Manufacturer's didn't install them years ago because of patent infringement issues. They don't install them now because it would be an admission that their hull design isn't all it should be.

Consumers ultimately decide what works and what doesn't. You can probably think of a number of boat related "gimmicks" that never made it past the second year becaue of lack of sales. Manufacturer's don't continue manufacturing things with no market. The fact is that the DoelFin not only continues to be manufactured after 35+ years, but a number of imitators have come along as well.

In my neck of the woods fins are everywhere. I've been running one for 30 years and don't pick up weeds, haven't broken the lower unit and found it does all it advertises to do!

 

[metriccrescentwrench]

Re: Planing attachment on cavitation plate - are trim planes better

Again, if "whale tales" worked ....

As JimS said, they do work. They provide additional lift which helps the boat get on plane at a lower speed, it's not (or shouldn't be) very difficult to understand. I had a boat that had a tale on when I bought it, tried it without but decided I liked it much better with it on. It made a big difference in how slow I could pull kids on a tube, as well as giving me better speed control when pulling my son on his wakeboard.

Drilling holes in your motor WILL VOID THE WARRANTY!!!!

OK, let's have a show of hands..... how many of you reading this thread have an outboard that's still covered by the original warranty? (I don't, and probably never will).

 

[wrench 3]

Re: Planing attachment on cavitation plate - are trim planes better

I Think I have the wiring doped out ( :laugh: ) Looks like a couple of DPDT Mom-on -off- Mom-on will do it, just have to be sure they will carry the fused 20 amp supply.

Sounds like your on the right track Seafever. If you have any problems let us know.