Need Help

[T-BO]

I recently done my 1982 Prather offshore deep V 40" over to electric. Motor is a TP4050 1570KV, ESC Seaking 180A V3, Battery is a 5S 6000mah 50-100c. I'm running all the stock prather running hardware kit #1020. My problem is when I give full power it raises the back of the boat out of the water. I put the cg 12 inches from transom per manual which worked great with the 7.5 nitro engine. I moved the battery all the way back to make it tail heavy, Changed angle of strut and depth of strut. Nothing seems to work. These are some of the props I've tried X442, X445, detongued CNC42x67, Prather b220, X447. I've had this boat since 82 and just getting back into RC boats after 30yrs. I would appreciate any and all advice given.

[rol243]

well your issue is not the props used as there non lifting type. where does the prop shaft exit the hull ? at transom or under hull ? any trim tabs fitted ? your c.o.g sounds correct.

[T-BO]

The prop shaft exits under the hull 6" in from the transom. The flex cable is 1" from bottom of boat which is adjustable. I do have trim tabs on it which are 4" by 1-1/2" stainless bendable plate. I hope this will help.

[TRUCKPULL]

All the props listed above are surface props.
You setup as is, requires a submersible prop.

I would suggest you keep the props that you have and change your setup to a surface drive.

You will like it much better.

99.9 % of the boats on this Forum are surface drive.


Robert - where in NY are you?

Larry

[fweasel]

well your issue is not the props used as there non lifting type. where does the prop shaft exit the hull ? at transom or under hull ? any trim tabs fitted ? your c.o.g sounds correct.

I disagree, the Octura x series props can lift the transom. Perhaps not as much as some, but significantly more than a prop like an ABC 17/45 series. The bigger issue is that those props are designed as surface piercing props, intended to run only half in the water, at most. Installing them fully submerged under the hull is going to cause all sorts of issues.

I'm not familiar with that hull, but you'll likely be best served with redrilling the transom and running the stuffing tube and flex cable out through the back, approximately 5/16"-3/8" above the keel. You'd need to raise the strut to support the prop shaft at the new height, possibly even replace the strut with a different design altogether. Again, I have no experience with that hull or the hardware in place.

[rol243]

yes definetly remove the shaft log and re fit the shaft log so the shaft will exit out the back of transom as low as you can drill the hole, lets say the center of shaft log will be no more than 1/2 inch from hull bottom. you can then use your non lifting props to suit the power output / rpm,s of motor .

[T-BO]

Just outside Syracuse NY

[Fluid]

T-BO: as others have stated, you will have better luck with a full surface drive - things have changed in boat setups over the past 30 years. This change will reduce the transom lifting and allow the use of larger, more efficient props for more speed. A strut adjustable for height is best, but drilling the transom so that the cable exits about 1/2” above the keel would be a good place to start. This gets the prop out of the water so it can unload for less amp draw and more speed and will reduce transom lift. For a large hull like that I might have chosen a different motor/battery combo, but yours can be made to work.

The tiny props originally used will not work well with a surface drive. I would start with the x447 but you might be able to increase that to an x450. When testing props, only run for one minute, then bring the boat in and check the temperatures on the motor and ESC. Nothing should be above 110* F. That is a big boat for just a 6000 mAh battery, you may want to consider running two packs in parallel (NOT in series,) to increase run time and reduce stress on the ESC. Or not.

Oh, don’t forget to use a water tight hatch on the boat, Hyperformance Products may still carry them. Water and electrics do not mix well together.

Here are some reference threads:

https://forums.offshoreelectrics.com...hlight=Prather

https://forums.offshoreelectrics.com...hlight=Prather


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