Need Help Smart Tabs II for big boats???

[ingalp01]

Hello all,

I think I want these??? Nauticus ST1610-160 Smart Tabs II Trim Tabs???

I'm new to the forums, but not to boating... I know this is a long post, but I wanted to provide as much info as possible for y'all to chew on... Thanks...

I recently purchased a very well maintained 1982 25ft Chris Craft (Viking) Cabin Cruiser. I had it on the lake over the Labor day weekend, and had issues getting up on plane when fully loaded. (Big Boat, 75 gallons of fuel, 35 gallons fresh water, 7 people & 4 coolers... No wonder, right?)

I had to ask a couple of buddies of mine (260 & 190 lbs. respectively) to go forward to get the boat up on plane. After most of the first day, with fuel burn off, and dumping some of the 35 gallons of water I had in the fresh water tanks, she would plane out pretty well, and achieve a top speed of 23mph. Day two, with less people, less coolers and less fuel and water, she planed out OK, and achieved 27mph.

(Prop is a 15 inch 16 pitch 4 blade aluminum and WOT RPM's are bout 5000)

I have been researching Trim Tabs and am very interested in the Smart Tabs, as I'm on a big fairly calm lake in Georgia, and don't like to fiddle with a lot of Buttons. Tubing, cruising, and anchoring are the main uses of this boat.

Does anyone have any info on the Nauticus ST1610-160 Smart Tabs II Trim Tabs, as I think this might be a decent cure. Oh, there is currently a hydrofoil on this boat as well, but from what I have been reading, I would probably want to take that off to add the tabs???

Thanks for any and all advice...

 

[superbenk]

Re: Need Help Smart Tabs II for big boats???

You know there's a maximum weight limit on that placard in addition to a max persons Sounds like you might have been on the heavy side. I've never had a boat that big so I don't know if what you're describing is heavy, but it sure sounds like it is.

I love Smart Tabs on my little 18' boat, but I think if I had something your size I'd want adjustable tabs.

 

[ingalp01]

Re: Need Help Smart Tabs II for big boats???

Thanks, and yes, I know there's a maximum weight, but it just mentions gear and persons, 9 persons & I want to say 1800 lbs. I'm sure I was close, but still based on what I've seen, it seems like the smart tabs would work.

It's all physics, right? Water pressure distributed over the width and depth of the smart tab = X amount of lift. Bigger tabs X 2 actuators @ 80 lbs resistance each = 160 lbs. of actuator resistance = X amount of lift on the rear of the boat. Seems to me if a small tab works so wonderfully on a small boat, and I have seen the positive reviews here, then a big tab should work just as well on a big boat. I am in a lake, so no following seas to contend with. I think I am convinced, and have e-mailed the Smart tab people, just haven't heard anything back yet.

I was hoping I would find someone on here with a larger boat that had some input, but maybe I'll end up as the experiment, and hopefully the success story.

Thanks for the input.

 

[ingalp01]

Re: Need Help Smart Tabs II for big boats???

Moreover, if I can get the thing to plane out with the smart tabs, then perhaps I can move on to a higher pitch prop 18? possibly, and lower my WOT RPM's, which are currently in the 5000 to 5200 range, and maybe get another couple of MPH out of her???

Is 5000 to 5200 RPM's High on a 1982 model Mercruiser 260? It's basically a chevy 350 or 5.7 L, which I know can spin up to around 6000 when properly built and tuned, but I think 4700 would be a good safe RPM's for a 28 year old motor. Granted it only has 370 hours on it.

Any thoughts on that would be greatly appreciated as well...

 

[ingalp01]

Re: Need Help Smart Tabs II for big boats???

If anyone is still reading this thread... Just for S-_-_-Ts and giggles, how much of a pain in the butt is it to install a typical helm controlled type trim tab???

 

[airdvr1227]

Re: Need Help Smart Tabs II for big boats???

Thiose sound like some high RPM numbers for that motor but I don't have anything to suggest that you're incorrect.

 

[NSBCraig]

Re: Need Help Smart Tabs II for big boats???

Talk to Joe( oops I mean John) from smart tabs he's on here.

 

[nlain]

Re: Need Help Smart Tabs II for big boats???

I do not know how they would work on your boat, they are great on my 19' boat. John can and will guide you thru what you really need.

You can call John at this number, 800-233-0194 .

Link to website: http://www.nauticusinc.com/

 

[ingalp01]

Re: Need Help Smart Tabs II for big boats???

Thanks guys, I have an e-mail in to the Smart Tabs folks, so maybe John or someone on his staff will clue me in to what I may or may not need.

In reference to the Prop issue, I have another post addressing the RPM's. I thought that was a bit high, and it seems like an 18 pitch prop would bring me into the proper RPM range, so long as the Tabs will help me get on plane.

Thanks again...

 

[ingalp01]

Re: Need Help Smart Tabs II for big boats???

Hey there, I have yet to hear anything from the Smart Tabs people, and the 800 number listed above sounds like it goes to a computer, or fax.

I've tried it several times to no avail. No reply to my e-mail either. I have read many great things about Smart Tabs customer service on these forums, but I can't even get a hold of them. Are they still in business, or are they going belly up? Does anyone know?

Thanks...

 

[nlain]

Re: Need Help Smart Tabs II for big boats???

I know they were way behind on answering emails and also could not get to all of the phone calls a while back, they were working on a solution to the problem, maybe they have not got things right yet.

 

[NHGuy]

Re: Need Help Smart Tabs II for big boats???

If the hydrofoil is easy to remove try running without it, but they are made for your exact issue.
Also on the prop pitch question, yes a higher pitch will lower your wide open throttle rpms. And if you have the typical engine that is the right thing to do for engine longevity. Most GM small blocks want to run 4200 to 4600 rpm wide open. I think 454's are OK to higher rpms such as you mentioned, someone will come along and tell you. BUT, if you control your wide open revs you get better hole shot with the existing lower pitch. And conversely the taller ratio will take off slower but may achieve higher top speed.
Is the bottom clean? Dirty bottom=bad liftoff.
If you ever do end up needing a prop look into stainless due their efficiency at putting your existing power to best use, they cost more but they are more effective. Only drawbacks are cost and that they don't give on impacts. So if you hit something and the hub doesn't release you can break drive parts.
I used to pilot my father in laws low powered Larson 21' cuddy with adjustable tabs. Without the tabs it would have been awful, with them it was very enjoyable.

 

[Jdeagro]

Re: Need Help Smart Tabs II for big boats???

Ingalp;

Sorry for the trouble in getting through to us. The number is 800-233-0194, and the regular number is 440-746-1290. Anyway, let me try to help here and now.

I do not think you need to go to the ST1610-80, I would try the ST1290-80 first. You can always swap the plates out for the larger size if needed.

The hydrofoil is a trim plate. The running surface of the adds additional lift to the stern. However, there are two major issues which make them undesirable. One is that the lift is concentrated in the center of the boat ("V") which can cause listing and excessive role in turns, and the other is that they produce increasingly more lift as the boat speed increases. In other words you get more lift when you do not need or want it, as it drives the bow down. Since they are fixed, they can not be adjusted. What does this say? There is no ability to adjust the hydrofoil to match the boat size. One size fits all so to speak. Yes I know they have a few different sizes, but not enough. One the less you do not want to lift the boat by the motor.

Back to your issues, the trim tabs will give you additional lift on the stern at slow speeds so that during acceleration the front and back of the boat are lifted at nearly the same rate. This minimizes or eliminates the "Hole" so that the available HP which was used to climb up hill is now used to accelerate forward.

In any event, use the ST1290-80.

 

[ewenm]

Re: Need Help Smart Tabs II for big boats???

i have a 32 footer and i have hydraulic trim tabs, personally i want control of my tabs, i suspect the auto or smart tabs might work well on smaller boats but from my limited experience i also want to be able to use my tabs to balance the boat side to side to allow for people and cross wind.

the fact that your prop allows you to get to 5000 rpm indicates that the previous owner knew it was tough to get out of the hole, and slightly under propped it to suit.

my 32 is the same i can do 5000 rpm flat out where it should be 4800 so i should increase the pitch a little, buuuuttt the way it is allows me to have 6 - 7 adults on board near full fuel tanks and still easily get on the plane, i also can cruise at 27 mph and around 3400 rpm
so for me its perfect

hope that helps

 

[ingalp01]

Re: Need Help Smart Tabs II for big boats???

Jdeagro;

I'm glad to finally hear from you, I was hoping you would eventually chime in. I know you on the company and all, and I don't want to seem hard-headed, but according to your online application chart, the ST1610-160 would be the appropriate sized tab for my boat, when my boat is fully laden. I was hoping to hear from you or your people in person, because my only question would be the weight at this point.

My boat depending on the load, passengers, gear, fuel , etc... falls right between 6000 & 7000 lbs. Should I choose the ST1610-160 and reduce the resistance when unladen, or choose the ST1610-120 and increase the resistance when laden?

Thanks, hopefully I can have this figured out soon and place an order.