Finding a balance point & balancing a boat .....

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  • gsbuickman
    Fast Electric Addict!
    • Jul 2011
    • 1292

    #1

    Finding a balance point & balancing a boat .....

    After reoutfitting my mean machine with a 3656/m442 and posting this 2nd video after a strut adjustment, I still had work to do. As pointed out by flraptor she was running wet (too nose heavy) which also cost on speed. She was also pulling to the left but that's just a rudder adjustment....

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    I got my cooling sleeve in today for my 3674 (2350kv) so I went back to work on it for another go round. Here is how I find my balance point on this hull. Everyone has a little bit different idea on how to do it but this works for me. I just thought some people might find this useful since I don't recall seeing an actual thread on how to balance a hull.

    Start by outfitting your boat just as it would be as if it were in the water with the batteries, floation foam, hatch and everything else in it that you need to run. Then find out where your starting point should be. Then get a wooden dowel or in this case a broomstick and find your balance point as if it were a teeter totter.



    I use a measuring tape to break this hull up into percentages ie: 25%, 50%, 75% & 100%. In this case this hull is 29" long, so from front to back 25% is 7.25", 50% is 14.50", 75% is 21.75" & 100% is 29".. I can subdivide the percentages from there.



    With this stepped Hull, I want to start with a 70/30 split front to rear, so the balance point is on the last two steps when its on plane. This is pretty close to start with.




    I pulled the 3656 & bolted in the 3674 (2350kv) and swapped in an m445 prop too. I fixed the rudder and slid the lipos back a few inches. Here's the layout.





    Here's the battery placement if your wondering, from the sponson tip.



    If I have time after Easter services tomorrow, maybe I can test her out & see how she runs now. If you have any tips on how you balance boats, chime in, I'm sure a lot of the new guys that have showed up here recently would appreciate it. Thanks :
  • boredom.is.me
    Senior Member
    • Jun 2009
    • 595

    #2
    The general rule of thumb is 30% from the rear of the ride pads, which is the same as 30% from the transom in this case. That would be about 10" here.

    Where did you get that awesome cooling jacket from?! Glad to see it being put to use instead of sitting in a box.

    Comment

    • Luck as a Constant
      Make Total Destroy
      • Mar 2014
      • 1952

      #3
      Finding a balance point & balancing a boat .....

      The second step is the best place for them.

      Sent from my iPhone using Tapatalk
      There's a hole at the center of earth where the rest of the world sinks but i stand still...

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      • greenblast
        Senior Member
        • Apr 2007
        • 292

        #4
        30% is a great starting point. i have a meanmachine that i have set with up with everything from nicad to twins to 40/82 brushless and the balance point is always the same. i hope you support that motor before you run. happy easter to you and yours. cool paint b.t.w

        Comment

        • srislash
          Not there yet
          • Mar 2011
          • 7673

          #5
          I have stuff to add, I made this hull balancer one evening with some spare Ranger board that I had leftover. Works great on monos and on cats as long as it is made wide enough


          Comment

          • TheShaughnessy
            Fast Electric Addict!
            • Mar 2011
            • 1431

            #6
            Not balance related but, there are 5 connections from each battery to esc, I would do something to alleviate that issue. You will likely end up with some pretty hot wires and connectors. Also those pacs don't look like they are up to the challenge of supplying that 3674 with adequate power. Just my .02 though, you might not have any issues.

            Comment

            • ls1fst98
              Senior Member
              • Oct 2009
              • 859

              #7
              my mean machine balances perfect at 30%, its like 9,75 inches or so. and it runs great, turns on a dime and gives 9 cents change. no risk of blow over and takes chop dead flat. your motor mount appears to only have 2 bolts holding it in place, that is worrying to me

              **edit** my packs sit almost at the transom. your balance point looks like its 18 incehs forward, this is way to far forward and will be very wet
              Last edited by ls1fst98; 04-20-2014, 11:44 AM. Reason: additional info
              HPR 135 redemption, HPR C5009, modded zelos 36, 32 boats and counting.
              Flier ESC dealer, pm me for details.
              https://www.facebook.com/groups/EliteRCBoats/

              Comment

              • gsbuickman
                Fast Electric Addict!
                • Jul 2011
                • 1292

                #8
                Originally posted by srislash
                I have stuff to add, I made this hull balancer one evening with some spare Ranger board that I had leftover. Works great on monos and on cats as long as it is made wide enough


                Nice Shawn, thanks for sharing. I like it

                Comment

                • gsbuickman
                  Fast Electric Addict!
                  • Jul 2011
                  • 1292

                  #9
                  Originally posted by TheShaughnessy
                  Not balance related but, there are 5 connections from each battery to esc, I would do something to alleviate that issue. You will likely end up with some pretty hot wires and connectors. Also those pacs don't look like they are up to the challenge of supplying that 3674 with adequate power. Just my .02 though, you might not have any issues.
                  Good catch bro . It's a 60A ESC; but the motor to ESC is 5.5mm, the ESC to series connector is also 5.5mm connectors. The only deans plugs is the series connector itself. Its just a sportboat, but I have an anchor for the front of the motor & some 40c packs for it. I posted this real early this morning b4 bed, I was too pooped to set them up too......

                  Comment

                  • gsbuickman
                    Fast Electric Addict!
                    • Jul 2011
                    • 1292

                    #10
                    Alright, I soldered up a series connector on 10awg lead with 5.5mm connector's, so I can run my thunder power 3850!mah 4s cells.





                    I also rebalanced it on the second step @ 9.75" w/ the 4s cells.



                    Comment

                    • gsbuickman
                      Fast Electric Addict!
                      • Jul 2011
                      • 1292

                      #11
                      I put the front anchor on the motor, unfortunately the 3674 is 1/8" - 3/16" too long for this motor mount. I dropped the rear motor mount to the middle bolt hole, now the rear of the water jacket is sitting right on the Hull but it's bolted down. this lets the front motor mount set squarely in the saddle, since those bolt holes don't line up anchored it with gap filling medium CA glue, across the top., back & front. it feels rock solid I can't budge it, I hope it holds alright ....






                      Comment

                      • greenblast
                        Senior Member
                        • Apr 2007
                        • 292

                        #12
                        i think your headed for trouble with that set up. i always try to imagine a bullet traveling up my stuffing tube and i want it the bullet to leave the center of the rear bearing. you looks like it wouldnt hit the rear of the can.it changes direction between the stuffing tube and coupler

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                        • gsbuickman
                          Fast Electric Addict!
                          • Jul 2011
                          • 1292

                          #13
                          [QUOTE=greenblast;561347]i think your headed for trouble with that set up. i always try to imagine a bullet traveling up my stuffing tube and i want it the bullet to leave the center of the rear bearing. you looks like it wouldnt hit the rear of the can.it changes direction between the stuffing tube and coupler[/QUOT

                          In this case looks can be decieving mesa' thinks. I think its the piece of fuel line I have squeezed in between the stuffing tube & Collette that makes it look off. Its straight & spins free w/o wobble or resistance.

                          Comment

                          • Luck as a Constant
                            Make Total Destroy
                            • Mar 2014
                            • 1952

                            #14
                            Are you not concerned about running a 60amp esc on a 3674 2350kv on 4s with m445?


                            Sent from my iPhone using Tapatalk
                            There's a hole at the center of earth where the rest of the world sinks but i stand still...

                            Comment

                            • gsbuickman
                              Fast Electric Addict!
                              • Jul 2011
                              • 1292

                              #15
                              [Be as a Constant;561368]Are you not concerned about running a 60amp esc on a 3674 2350kv on 4s with m445?


                              Sent from my iPhone using Tapatalk[/QUOTE]


                              Not really. There are a couple 29" Geico's here running this same setup on 4s w/ 80A esc:'s, Since I don't have an extra ESC at the moment, I back cut the prop a 1/16" to cut down on low & mid throttle amp draw. it doesn't matter one way or the other I'm upgrading to a better ESC anyway.

                              You ever think about being a food critic ?? ......

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