Smart Tabs right for my boat?

[mattkenton]

I have a 1975 Trihaul SeaSprite Cougar 15'. Non trim tilt engine. Getting about 34mph with a 17" prop. Was wondering if Smart Tabs would help my overall top end enough to make it worth the $150. Thanks.

 

[tashasdaddy]

Re: Smart Tabs right for my boat?

what engine is that?

 

[crb478]

Re: Smart Tabs right for my boat?

If you are not having handling problems with your boat you do not need smart tabs. If it takes you a long time to get the boat to plane out or if the bow rides high they will absolutely help out. They will also help with turning and prop torque. I would not get them to try to pick up any speed. I doubt that will will pick up more than 1 or 2 mph. I would try to maximize the motor set up first. Raise the motor as high as you can without cavitating, and set the trim pin to the best overall setting first.

 

[Mark42]

Re: Smart Tabs right for my boat?

Its always best to try to maximize the current setup before spending money on hardware. Like crb478 said, check your engine height and try different trim pin settings. Then make sure your engine is reaching it optimum RPM with the prop you have. If not, change it. Changing the prop can make a huge difference.

Too many times people add smart tabs/trim tabs to mask simple setup issues. Then praise how well spent the money was when they could have achieved the same results for just a few hours work.

My MFG took about a 3 trips to the water with tool box and spare props to get it setup right. Tested different pin settings, changed props, and changed weight distribution. I later replaced two 6 gallon portable gas tanks under the splashwell with one 14 gallon permanent tank up in the bow. That really evened out the weight distribution and the boat rides really nice and level now.

 

[mattkenton]

Re: Smart Tabs right for my boat?

Alright. This Monday i will take everyone's advise and mess with the pin settings. The cav plate sits level with bottom of boat so i know its not an issue. I didn't even think about the trim pin. Makes a lot of sense now that you mention it.

And its a 1975 70HP Evinrude.

 

[tashasdaddy]

Re: Smart Tabs right for my boat?

are you using GPS or pitot speedometer to get you mph. pitot speedos, are only approx mph, the faster you go less accurate. how many people on board. tri hulls are slower than a V. 34mph with that set up, is not that bad.

 

[mattkenton]

Re: Smart Tabs right for my boat?

I used a Garmin Etrex Hand Held GPS. Only me on board. I know trihauls are slower but i know i can get it to at least 37 with a little tweaking. I have confidence!

 

[crb478]

Re: Smart Tabs right for my boat?

Alright. This Monday i will take everyone's advise and mess with the pin settings. The cav plate sits level with bottom of boat so i know its not an issue. I didn't even think about the trim pin. Makes a lot of sense now that you mention it.

And its a 1975 70HP Evinrude.

You may be able to get the cav plate an inch or so above the bottom of the boat and still be fine. You could pick up that extra 3mph you are looking for right there.

 

[tashasdaddy]

Re: Smart Tabs right for my boat?

the only problem with raising a 1975, is making sure you are still picking up cooling water. does the motor have a tale tell stream? i can remember. if it does not install one.

http://forums.iboats.com/showthread.php?t=222677

 

[mattkenton]

Re: Smart Tabs right for my boat?

I will look and see if i can raise the motor up another peg on the transom. I did install a "aftermarket" tell tale. Used the forum here to do the job. Thanks for that by the way too. What is the best way to lift that engine once i loosen it from the transom? A jack i suppose? Or should i use the engine hoist so not to damage the skag?

 

[tashasdaddy]

Re: Smart Tabs right for my boat?

cherry picker is the best and safest. it is extremely hard to balance in place to get the bolts in. i'm lucky, my neighbors hoist stays at my house more than his.

 

[BillP]

Re: Smart Tabs right for my boat?

Raising the motor will give more speed than adding tabs. If the cav plate is even with the boat bottom you can probably raise it two holes. Water pickup is no problem. You can tell when it starts getting too high when the prop cavitates during a mild easy turns or when in choppy water. Stop raising when the cavitation bothers you. The higher the better for speed but it lets the prop spin faster and means re-proping when raising to max height. Watch your rpms.

 

[steelespike]

Re: Smart Tabs right for my boat?

Once you get the setup fine tuned a stainless prop or a Hustler turning point will help combat venting and may allow even more height.

 

[mattkenton]

Re: Smart Tabs right for my boat?

I have a 17" prop so after raising would i maybe upgrade to a 19" if my RPMs are within range? I am not 100% on how that works. I know the RPMs change 200 per inch of pitch. But does raising allow for a higher pitch? If it does, and that gains me more MPH, i am all for it.

 

[crb478]

Re: Smart Tabs right for my boat?

If you are able to raise the motor and pick up more speed you will also pick up more rpm's. Not wanting too many rpm,s you may need to get a prop with more pitch to reduce the rpm's, in your case from a 17 to a 19. The 19 will probably pick up still a bit more speed while reducing your rpm's. You may have to experiement to get the most speed and still be in your recommended rpm range.

 

[mattkenton]

Re: Smart Tabs right for my boat?

Ok. So i used the trim pin and i gained about 1mph. going to try the engine hoisting next for the next 3-4mph increase(added with a 19-20 pitch prop). I also had a bit off "bogging" down when i went underway. Maybe carbs? it seemed to clean itself out for a while then bogged again. strange. Any suggestions?

 

[kandil]

Re: Smart Tabs right for my boat?

You have self cleaning carb never heard of it check your fuel system. when was the last time you I mean your carb cleaned thim self? maybe it is time to switch it to manual cleaning good luck with your last 4 miles

 

[Mark42]

Re: Smart Tabs right for my boat?

Ok. So i used the trim pin and i gained about 1mph. going to try the engine hoisting next for the next 3-4mph increase(added with a 19-20 pitch prop). I also had a bit off "bogging" down when i went underway. Maybe carbs? it seemed to clean itself out for a while then bogged again. strange. Any suggestions?

Yep, that bogging could be carbs. Try a seafoam treatment, fresh plugs, and fresh fuel filter. Also check for proper venting on the gas tank so its not working hard to suck the fuel.

Also, how is your prop? full of nicks and dings? bent blades? If its not in great shape, take it off and smooth any rough edges with sandpaper or file. Straighten any bent blades. A messed up prop takes a lot more energy to do the same job as a clean prop.

 

[mattkenton]

Re: Smart Tabs right for my boat?

I do need fresh plugs. They are atleast 2 yrs old and have been sitting for that long atleast as well. The prop is in mint condition. Ans there is no fuel filter on this engine. Suppose i should put one huh?

 

[NSBCraig]

Re: Smart Tabs right for my boat?

Isn't there a screen under the fuel pump cover thing. (Sorry for all the jargon)

Maybe it clogged up since you don't have a inline one?

Just a thought.