Trim tabs- why no factory option or standard?

[QC]

Re: Trim tabs- why no factory option or standard?

A lot of good info here mixed in with some misconceptions. This whole thing about "need"ing tabs is rather silly. Tabs are a tool, if you don't want more ways to manipulate your hull, then OK, good on ya . . . But, whether a hull is 50 years old or brand new, it is a compromise. No design does everything well, but tabs will extend the "good" range of performance. Helm adjustable tabs will offer even more flexibility.

On the heavier engine thing, yes, most boats have more power today than a similar boat 20, 30 or 50 years ago. However, power density (power to weight/size ratios) has improved so effectively engines have actually gotten lighter. There are exceptions, but small blocks do the work of big blocks these days and there were no 300 bhp OBs 50 years ago, so you could argue that there were no 500 lb options for a similar output motor and drive package back then . . .

Also, many, many older boats are straight inboards, they plane off well with little to no bowrise because weight is more forward, and the angle of the dangle is good for hole shot. They are all slower and less efficient than the same with a trimmable drive system and the same power. This is true to the point of not even being debatable . . .

 

[dsiekman]

Re: Trim tabs- why no factory option or standard?

My old Cobalt, a 1994 252, had no need for trim tabs. Even with a full load of people she had no trouble getting on plane with the carb'd 7.4. My new(er) boat is a 293 with twin screws. Also no problem getting out of the hole, but tends to need the tabs to level side to side. I am guessing this is because the center of gravity is much different with twins. I know they were factory installed, though I do not know if they were an option or whether they were standard. With Cobalt it may have been like trying to buy a new car without a stereo or AC - although it is usually an option there's not much chance of finding one on the lot without one. Just speculating.

 

[Tabman]

Re: Trim tabs- why no factory option or standard?

It's worth noting that the first remotely controlled Trim Tabs were developed in 1959 aboard a 28 foot Chris Craft.

Those of you old enough might remember the practice of installing wooden wedges (shims) on the bottom of the hull in an effort to help older wooden boats get their bow down at lower speeds. Sort of like the hook that it molded into the bottom of some boats today.

The problem was that a static hook or wedge makes lift and holds the bow down when you don't want it, like running an inlet in a following sea. This is exactly what happened to Charles Bennett. After the indecent Bennett, who was a pilot, developed "movable flaps" on the transom to produce lift when it was needed and could be retracted so the boat can run bow up when needed.

I don't subscribe to the "a well designed boat doesn't need Trim Tabs" school of thought. After working with many boat builders and designers over many years I realize (as do they) that Trim Tabs allow the positive traits of a well designed hull work over a broader range of speed, loading and sea conditions. A boat running "on its lines" is more efficient than one listing or running bow high at lower speeds. Trim Tabs allow the boat to "run on its lines"s at lower speeds, thus keeping its forefoot in the water, cutting the on coming waves. Trim Tabs are more effective than using power Trim since adjusting the boats trim with the propeller forces it to run at an angle to the waterflow, reducing the efficiency of the thrust and increasing prop slip.

In a way smaller boats benefit more from Trim Tabs than larger boats. Being able to keep a smaller boat's bow down at lower speeds will make it far more comfortable running in chop. And small boats are much more affected by changes in loading and passenger placement than a larger boat. If I moved around in my 20ft walkaround it did a lot more to the trim than if I move around on a 36 sportfish.

Many small boat manufacturers do offer Trim Tabs as standard equipment or as an option, Flats boats in particular almost universally run with Trim Tabs regardless of how small.

There are many good points raised in this thread and I thought I would offer my views, but of course I am a little biased!

 

[Chinewalker]

Re: Trim tabs- why no factory option or standard?

Lol. put three fat people on one side of the boat while under way. You'll wish you had tabs.

If three heavy people sat on the same side in my boat I'd tell one or two of them to move their behinds to where the boat would be balanced!

 

[Pirate_40]

Re: Trim tabs- why no factory option or standard?

^^^^

Well I guess you could if your friendly with them. I would consider it improper to ask a guest to move to another area due to their weight being an issue.

It's kinda like asking big ol' Aunt Tillie to eat her Thanksgiving dinner on the garage slab so she don't bust through the floor joists in the diningroom.

As the captain of the vessel you make adjustments to the way you run and let your guests feel comfortable. We as captains of our boats are supposed to be the experienced ones. Why allow our guests to feel insecure with us by asking them silly requests that we should be able to compensate for.

 

[haulnazz15]

Re: Trim tabs- why no factory option or standard?

^^^^

Well I guess you could if your friendly with them. I would consider it improper to ask a guest to move to another area due to their weight being an issue.

I don't think it is improper to ask of someone at all. It isn't (usually) an issue of their personal weight in particular, it's the sum amount of weight on one side/section of the boat. If swapping one person from one side to the other makes the boat ride level, then everyone would be happy. On smaller boats (and those without trim tabs) I usually look around to see which side of the boat i should sit on to help balance out the weight.

To go along with the aircraft references above, I don't hesitate to assign seating in the aircraft based on someone's weight. Althought in the airplane, there's usually a safety factory with the weight & balance I'm working with!

 

[ingalp01]

Re: Trim tabs- why no factory option or standard?

I'm not a tour boat captain. If I have heavy guests aboard, or if they all congregate on one side of the boat. I have no problem asking them to re-distribute their load in order to keep the boat on an even keel.

If you are on the water, with "water people" they will understand. If you brought non-water people to the lake / ocean / river, then you are asking for trouble anyways.

"water people" are generally laid back, easy going folk and if there are mechanicals, or everything doesn't work perfectly that day, they will understand and roll with it. Non-water people are just ballast.

Just ordered non-adjustable Smart Tabs II for my 25 footer. I believe they will do everything I need on the big lake I choose to cruise on.

 

[rodbolt]

Re: Trim tabs- why no factory option or standard?

my 21 seapro has lenco electrics and I love my tabs.
if the wind is heeling it over or the 5 passengers are heeling it all I have to do is touch a button and its level.
running into a head on chop, lower the bow and it rides easy.
taking off in shallow water, as in at the Blue Crab tavern in colington NC raise the jack 3",trim engine full down,extend tabs full down, check depthsounder.
if depthsounder shows more than 18" open throttle rapidly and it wont disturb the mud on the bottom.
wont own another boat without trim tabs.
jack plate is nice too.
2nd station means I stay dry in a chop.

 

[45Auto]

Re: Trim tabs- why no factory option or standard?

If you'd just get rid of all that modern crap and get you a wooden boat from the 50's, you wouldn't "need" all that fancy junk!

 

[Tabman]

Re: Trim tabs- why no factory option or standard?

Like this one?

I couldn't resist