AB Marine Intimidator Endurance Boat

[Peter A]

Burned up the motor on Saturday. I fitted some trim tabs during the week. To drill the transom I had to remove the rudder, but for some reason did not plug the cooling lines back in and totally missed it. 110*C on the motor and it is toast. Magnets are stuffed and wiring had that 'cooked' smell. On the up side the trim tabs did the trick and improved the ride and turning. Ordering a new motor today and I will be back on the water in a two-three weeks with this boat.

[tebby2]

Peter,

Sorry to hear about the cooked motor. It took me 2.5 months to receive my TP 4070 10Y motor after placing the order. Did you move the motor aft and shortened the length of the stuffing tube after installing the trim tabs, or did you keep the motor forward with the battery pack aft as in the picture?

Charlie

[Peter A]

Hi Charlie
I should have the motor in about two weeks. The first one took nearly a month due to Chinese new year. I have found TP pretty easy to deal with. Actually I have two motors coming as the one in my Q hydro decided to lunch it's rotor and take out the esc that same day as well.
No I have decided not to move the motor at this point, it is quite a lot of work. I have made up a new stuufing tube with teflon liner and will run oil instead of grease. I am thinking about putting bearings in the stinger instead of bushings also.

[Brushman]

Hello,

the TP 4070/440 can be used, but you have to optimize your boat until you get 70 KpH and 50A average, if the current is excessive, this motor is not the best and a larger one shoukd be used. You should also try a 4035/400 Xnova lightning, this is a good outrunner. But of course you need to reduce the amp draw before trying other motors. A video of your boat will help to see what should be optimized. About the liner, if you have a teflon liner, do not grease it, it is a cause of drag...

Vincent

[Peter A]

Hi Vincent
With the 4070 440kv motor the current draw is down to 52 A. While waiting for a new motor to arrive I have made and fitted a new stuffing tube with teflon liner. It will be lubricated with an oil feed. I will also do a little work on the prop and detongue it and that should bring down the current draw a bit further. I am ok with the current speed at 65 kph, any extra would be a bonus, however when the water gets rough you cannot use the speed anyway, and the gassers slow down also. Some of the boats I race against are 60+ inches in length, even up to 72", and can top out around 100kph. I will never be able to compete in speed, but I can on reliability and consistency.
I just need more time on water to test and tune.
Perhaps this hull is not the most efficient, if all else fails I can always put motor/esc into the Osprey and run that!

[fred 75]

Personnally, I believe in your Hull...
As you said, you just need more time to test and tune...It takes time to get a result...

[Beaux]

Nice job, those 10- 20 min runs are great.

[Peter A]

New motors turned up yesterday, but this Saturday is 2-laps and speed runs so it will be next week before I install the new motor in the boat.

[Peter A]

Well after getting the boat back on the water Saturday, it ran ok like before. However, the boat porpoises a lot due to the CG being too far back is what I thought. So to try and balance the CG I glued an 18 oz (420 gram) sinker in the front of the boat. It was a little too mouch wight and I had to move the batts back a bit but no worries there.
NO GOOD! the boat still porpoises, worse when it gets going. I think the weight has a pendulum effect, so it was hard going for a twenty minute race yesterday. With my first offshore race of the year this coming Saturday I have two choices. Try and remove the epoxied (that is I dropped the sinker in the nose and poured resin in around it!) sinker, or swap the motor and esc into my Osprey, which does run well and I think is a better boat for the job.
This boat I think needs to either be reconfigured on the motor mount/batt position side of things, or just put a bigger motor in and use for Oval racing. I think changing over to the Osprey is a smarter move at this point. I can get things changed over the next couple of nights and be ready for Saturday.

[tebby2]

Peter,

Did your trim tabs not work well enough to smooth out the porpoising? I sound like you hull have a slight "hook" deflection with a full load of 2 x 6s 16000 mAh batteries and equipment. It was my impression the AB Marine Intimidator 45" was a better boat to challenge after the gas boys rather than a light weight 42" Osprey hull.

[Brushman]

Hello,

the reason for porpoising can be the CoG position, but assuming it is actually around 30-35%, this is not the problem. I think you have to blueprint the rear section of your hull. look for a "deflection" upward on last centimeters to the transom. Use some filler and make surfaces flat. This can take a few hours but it worth it. Still I am not sure because I do not know this hull...
Good luck!

[srislash]

Peter, I had a heck of a time with a DF 35 getting it out of the same characteristic. I ended up with trim tabs. Just barely in water but it fixed it. My Pursuit hulls totally don’t need them.

[Peter A]

Ok so the hull is pretty good at the rear, to be fair it is probably better than the Osprey, but I will check it over still. It is a much larger hull overall than the Osprey, and I expect the Challenger 43. Those extra inches lengthwise and width make a lot more boat. What I have found is that is cavitates a lot getting up on a plane, and it really is designed to be running props in the 67/3 size range. A P245-250 is a lot smaller. I will see how the Osprey goes on Saturday but will probably continue with it for the season. I think I will be faster with better current draw/runtime. There is no point running a boat that is trouble. I will probably just put the TP 5680 motor I have in it and use it for oval racing and/or sell it on.

Shawn I have a DF35 also. I originally set it up for 6s but have changed it to a 4s setup. I set the motor quite far back and had a CG problem with the 4s setup so have a couple of fishing sinkers jammed in front of the battery tray under the pool noodle. Much better. At our 2-laps I just missed breaking my record set with a pursuit 4 years ago by 0.4 sec, but I did spin the boat before crossing the beam so lost a bit of time there. Now I have to prep another x447/3 as that prop got folded up on the side of a 72" 'ship' on Sunday. Fortunately I have two more of those props.

I have found from experience so far that 32% is the 'magic' number for CG. It keeps the boat flat when it jumps on waves and wakes. Too far back and the boat will come down on the back and dive the nose it, too far forward and it will bow steer and nose in. for flat water speed running the CG can come back a bit but this can tend to help induce chine walking.

[785boats]

Pete.
What is the angle of the strut in relation to the keel.
I find that a slight negative angle can get rid of porpoising.Sometimes the cog might need to be moved a tad further back too, with a slightly negative angle.

[Peter A]

Hi Paul
Now the boat is sitting up out of the way it is clear to see I had way too much positive angle on the strut. How ever I changed over to the Osprey and will run that again this year. I have the option of changing boats but I have to apply to the NZMPBA committee, however their condescending attitude (we allowed you to run electric (!!!), means I am not going there.

It was however a good move to run the Osprey, I took 4th overall for the day with 141 laps, that was behind 169-1st, 161-2nd, 146-3rd. I had a couple of glitches at the start of the first 20 min heat, the esc wouldn't arm and had to be re-calibrated to the tx, then the flex spun in the collet after half a lap, so after retrieving, fitted a new shaft and got 19 laps in. The next 20 min I managed 34 laps, only one lap behind the highest 20 min count on the day of 35 laps.

For now the Intimidator will get a TP 5670 650kv motor as I can bolt that in and run it as an oval boat, should help me retain back my open mono club title hopefully! Just need some more batteries!