Porpoising

[laxoholic93]

I just got back from a great day running my boat, but whenever it began to get up to high speeds, the boat began porpoising (the bow was bouncing up and down) and i had to slow down to maintain control.

Any suggestions?

[Diesel6401]

I just got back from a great day running my boat, but whenever it began to get up to high speeds, the boat began porpoising (the bow was bouncing up and down) and i had to slow down to maintain control.

Any suggestions?

Tuck the rudder forward (negative) and verify that your trim tabs are completly flush with the bottom of the hull and that they are completly neutral (use a straight edge to do this, don't eye ball). If problem persist tilt the trim tabs a bit down (negative). Remember small adjustments and one at a time. Happy boating

[laxoholic93]

Thanks man, I'll make these changes before i go out again tomorrow and report back

[Drewmugx5t]

I did the above and moved my batteries really far forward, like beside the motor. Today was the first day that it ran smooth at speed. I'm very happy with the boat and all the help from the nice people I have met on the forum

[wizard122]

Good setup tips

Thanks man, I'll make these changes before i go out again tomorrow and report back

Hi did you remove the battery trays and replace them with Velcro this will move the cg forward be careful with the trim tabs if you haven't installed adjustable brackets and just bend them you can brake the transom so you may have to remove them first. Post some photos of your boat and if I can help let me know. check out my Thread http://forums.offshoreelectrics.com/...ad.php?t=11601 theres lots of photos of my build I've learned a lot a long the way and am very happy with the latest set up.

[laxoholic93]

Just got back from some good boating. I did move the rudder to a more negative angle than before and flattened out the trim tabs. It made a HUGE difference but the boat would still begin to bounce at high speeds and usually flip And today the boat began to cavitate much more before getting up on plane than usual.

Everything I have is stock and I have decided that I am going to get turn fins for both sides. I use 2 Turnigy 2S 20-30C 5000mAh LiPOs.

Here is a video of today's run, but i never went to full throttle in it

http://www.youtube.com/watch?v=sRjmbAjYuqc

I really appreciate the help guys

[Diesel6401]

Just got back from some good boating. I did move the rudder to a more negative angle than before and flattened out the trim tabs. It made a HUGE difference but the boat would still begin to bounce at high speeds and usually flip And today the boat began to cavitate much more before getting up on plane than usual.

Everything I have is stock and I have decided that I am going to get turn fins for both sides. I use 2 Turnigy 2S 20-30C 5000mAh LiPOs.

Here is a video of today's run, but i never went to full throttle in it

http://www.youtube.com/watch?v=sRjmbAjYuqc

I really appreciate the help guys

Cavaitaing is because of your prop. The stock 3 blade prop has a higher top end but it's downfall is getting on plane. Buy a grim 42x55 prop and hold on cause it's going to be fast. The flipping issue is related to your cg, lipos are lighter weight. First thing you need to do is pull off the battery tray wood and move your lipos forward so that the leading edge of you lipo is inline with the forward edge of your rails. Thanks for posting the pics because we can tell now by looking that your problem is with your battery placement.

[boatman cmbc]

get the trim tab adjusters at kintec racing.com . crank them down and start back up u will find the sweet spot. my sv has been gpsed at 39.5mph ridin on the tabs and the prop. smooth as silk. also get the ss prather220 prop.

[boatman cmbc]

[boatman cmbc]

dont know if these pics came thru. but i sent pics of my sv

[wizard122]

Yes the problem is your CG the packs need to be move forward the stock prop slips a bit but works well a 2 blade prop will give you more bite My sons boat which is setup just like mine with 4000 30c turnigy packs ran 38 with stock prop batteries about 3/4" forward of motor mount. the port turn fin won't have any affect on porpoising just make it turn a little better to the left.

[laxoholic93]

So moving the batteries a couple cm forward should solve most of the porpoising problem?

[Diesel6401]

So moving the batteries a couple cm forward should solve most of the porpoising problem?

Moving the batteries forward will dramatically reduce the boats tendacy to bounce around at high speeds and flip so yes to your question. Adjusting the cg is one of the biggest changes you can do in a boat and aircraft for that matter. The only thing thats going to change the cavatation part and slow to plane is a new prop. Happy boating, by the way pay close attention to where wizard has his batts (notice the leading edge of his lipo is directly inline with the forward edge of the rails) because that is good battery placement.

[ms71171]

Jumping in on this old thread, but how did you guys remove your battery tray? Looks like there is glue or silicone holding it on? Dremel tool or just a hobby knife?

[Diesel6401]

Score with a hobby knife then pull off with pliars.