18' bowrider porpoising

[JaCrispy]

I can't comment on the smart tabs, but the hydrofoils do what they are marketed to do. My boat came with one and never porpoised and you can tell it was keeping the bow down. I've since removed it because I feel better trim control at higher speeds, but I can't see over the bow anymore not on plane.

 

[dan02gt]

Porpoising is quite common on small v6 powered I/Os. This is mainly due the the 1000lbs+ of motor and outdrive placed in the stern of the boat.

I agree with everyone on the Smart Tabs. Install them and never look back. It will be the best money you will spend out your boat.

 

[gt2003]

Agreed! Smart tabs are inexpensive and incredibly effective. They made all the difference in the world on my 2007 Tahoe Q6, totally different boat after they were installed. Now, quit hesitating and go get some!

 

[Scubacruiser]

I'm winterizing the boat this weekend, so I'll shop for smart tabs over the winter and install them in the spring. There just isn't enough time to buy, install and try out this year.

Thank you all for the advice!

 

[Tnstratofam]

When you do get them post back and let us know if that helped, or fixed the porpoising.

 

[Tail_Gunner]

The first thing you do is take a true straight edge about 5' long and look for a curve from the transom forward...other wise known as a hook. If that's present it may have been built in to provide bow lift..or the boat hull may have sagged...either way its permanent. Tab's will be the least expensive way to control this.

On my tub there is built in tab's are the far edges of the transom...using a four blade it's a bouncing Betty any time on plane and high trim, 3 blades reduce it but the easy way out is trim on the outdrive or tab's.

 

[Scubacruiser]

I have the smart tabs ready to install, but I have a dilemma. If I install them as far out as I can, I can no longer use the ladder on the rear as it will interfere with the tab actuator. Not a huge big deal, I may be able to modify the ladder slightly to work. I will also have to move the trailer tie down buckles. Again, no biggie. With this configuration, the upper mounting bracket will end up slightly into the curved surface under the swim platform (moulded in). I'd have to trim a bit off the corner of the bracket to make it sit flat against the transom.

I could mount them closer to centerline but that would mean moving the trailer bunks out about 8 to 10 inches. Which would mean adding new tie down eyes in the transom. Otherwise the tabs would sit directly on the end of the bunks. The bunks protrude about 12 inches past the end of the boat. I'm thinking this is to provide more tongue weight.

To move the bunks would require launching the boat first and then working on it in the parking lot. I'm worried that the front of the boat might sit too low on the trailer after moving the bunks.

I'm not sure what to do.

 

[Scubacruiser]

Hello!
ScubaCruiser shared an album with you.


Here are some photos of the stern.
View Album, http://s646.photobucket.com/user/ScubaCruiser/library/Campion Allante

 

[batman99]

Here are some photos of the stern.
View Album, http://s646.photobucket.com/user/ScubaCruiser/library/Campion Allante[/QUOTE

Trailer's tongue weight should be between 10% -> 13%. Recommend filling your boat with gas (assume rear gas tank), filling your boat with average towing gear, place bathroom scale under its tongue and do some calculations. re: If loaded boat is estimated 3,000 lbs, then its tongue weight should be between 300 and 330 lbs. If needed, move boat forward or backwards - until optimal loaded trailer calculations are obtained. And if needed, move the front support post forward or backwards as well (based on new position of the boat).

With loaded boat with proper weight ratio on trailer, then re-visit the bunks. The bunk board should only stick out 1" past the stern (lower transom). Sticking out longer is a waste. If not sticking out at all, then boat isn't being properly supported on the trailer. If bunk board is sticking out too far, simply peel back its exposed rug and cut the board off (via hand saw). Then, take peeled back rug and wrap around the cut end of the 2xn (2x4 or 2x6) bunk board. Staple / galvanized nail the as required.

After above in completed continue the Trim Tab installs. To view my boat's bunk board positions, surf: http://i178.photobucket.com/albums/w251/Spike99-Pictures/Boat Pictures/IMG_0018.jpg


Hope this helps...

 

[smokeonthewater]

Yep... First step step is get boat and trailer sorted out... Ideally the transom should be directly over the last crossmember.... Is your axle position adjustable? If so that is where you get your tongue weight adjustment.

Nauticus can sell you some simple mechanisms that allow you to flip the tabs up before loading so they will be above the bunks.
As for location outboard vs inboard... They should have about the same effect on porpoising either place tho they would have a little less effect on side to side movement.

 

[Scubacruiser]

Trailer has no axle adjustment. The transom lines up with the rearmost crossmember. There are no weigh scales nearby so I can't weigh the boat.

The bunks cannot be cut off at the ends - the metal brackets supporting the bunks at the back come almost to the ends of the bunks.

How much above the bottom plane of the boat do the PR500 brackets lift the tabs? These are the top brackets that swivel the tabs up for trailering.

 

[smokeonthewater]

They lift the tabs to be parallel with the bottom I believe.... Nauticus is known for excellent customer service and they have a phone number on their web page... I suggest giving them a call.

 

[Stingray185GXi]

If you install the PR500 brackets you would be able to simply lift the tabs up so they were level with the bottom of the boat anytime the boat was on the trailer. This way you should not have a problem even if the trailer bunks extend past the hull of the boat.

 

[Scubacruiser]

The PR500 brackets are probably the way I'll go. But how do I install the tabs over the bunks? I'll have to jack the boat up off the back of the trailer I guess. I have a 20 ton bottle jack, hmmmm...

 

[poconojoe]

So, is your drive actually going all the way down? Did you jack the trailer up or hang the drive over a curb or something to see?

And as far as your up position not seeming to go all the way up, I'm going to ask a silly question so don't get offended. You are pressing the button for the trailering position, right? Because it will only go up so far for normal use, and then you can make it go further for trailering. You probable know this, but I thought I would mention it because it can be a little confusing.

 

[Scubacruiser]

The drive goes all the way down - confirmed. When raising it, there is no trailering button, just the up/down toggle. It goes up as far as it can. There is about 1/4" clearance to the underside of the swim platform.

 

[smokeonthewater]

Hook the trailer to your truck and hook the boat to a tree... Pull ahead a bit to pull the back of the boat off the trailer a foot or so.

 

[mattisonjr]

I've been using a Stingray hydrofoil. Definitely much better with than without. I've tried the "Smart Tabs", but, for wakeboarding, they completely flattened out the wake. Not ideal when trying to jump a wake that doesn't exist anymore. Removed them after one trip out. Although they did get the boat to plane quicker. For me, the hydrofoil was the only way to go (aside from buying a new v-drive wake boat)

 

[Scubacruiser]

Just to close the loop...The Smart Tabs made all the difference in the world! I can now trim up nearly all the way while under power. No porpoising and nearly instant plane.
Now I just need to figure out why my trim is going down over time. Pump or rams I suppose. Time for some troubleshooting.

 

[smokeonthewater]

Glad they worked out for ya... Now you can get on board and help up spread the word!