powering large boats with electric

[Mel279]

I haven't got the pictures at the moment as I've send the boat to my friend to be replaced with a new drive system, as the stock one couldn't handle the power of the 10s setup. I have a video on youtube, just search epv 135 penaga if you interested to see it. Great built though

[expresscraft]

well here is the cut down boat, and a std MTI.I think the lower profile will help the boat get those higher speeds that the electric motors will achieve.plus the cut down airfoil should really come into play over that 60 mph mark.

[expresscraft]

Ok, I also cut down our 62" MTI for a customer. I'm pretty happy with how well everything lined up. It makes for a faster looking sleeker hull.Here is more pics of real cut down MTI's as well.

[expresscraft]

there is a thread on here about our seam work,so i will address it here on this build, this boat is cut down, and there are some gaps where the deck and hull where not ground down perfect,we do not spend a lot of time on this step, these hulls are meant to be painted, as with all fiberglass there is release wax to be removed and the shine needs to be sanded off, on these boats the seam needs to be filled, and sanded block sanding at that, then primed and filled some more where needed, then sanded some more, then you can paint the boat.Our boats are are only a foundation to work with, they are very solid and so is the seam, that is joined with a layer of 1 1/2 oz mat and another layer of 5.8 oz carbon twill,any painter will regaurd this filling and sanding as pretty minor,and it is.unless modeling is just not what you want to do. and that is fine, our boats are not for everyone,mhz makes big boats with semi finished seams for twice the price,we feel the average modeler can not scratch build his own boat, but can however fill and sand the seam.as you can see not having a overlapping deck that you get with a shoebox fit seam, the pay off is in the finished model.

[slowride]

I have two Expresscraft hulls a 36 and a 41 monos . As with many bare new hulls there was some refining to the seams needed before paint, but for the most part the work to smooth it out took but a few minutes no big deal. For the price I was quite happy and the boats are fast and strong. When im ready for a new hull I have no problem with buying another Expresscraft. Thanks Tom.

[expresscraft]

well, i got one set of 12s and one set of 10s packs from Mark F,they are 50c and 5000mAh, mark was up front that there would be a little wait on the packs,I did some checking along the way and afer kicking a lot of tires on line I think <ark is a great seller and would recommend him to anyone. I have also not seen any feedback to over ride the thought of the castle 2028 and ice 200 HV esc's. so unless there is another motor you guys would recommend.that is the way i will be going.

[expresscraft]

ok, I got two 830KV 11Hp motors from Chris fine,he was very helpful,I think they are the protues motors, I am sure I have that spelled wrong,but you get the idea.I had seen a thread somewhere that said the batteries should be mounted on top of the tunnel,Is this correct? I can not find that thread again,my plan is to mount the two motors on the tunnel with the struts 5" apart,I will be using L and R x457 props, my thought for the batteries was on adjustable slides mounted on the tunnel to allow adjusting forward and back for the batteries,Am I right on the batteries being mounted on the tunnel or should I simply mount them low in the sponsons and move them as needed, which sounds like the right way to go.Except what I think I read in this thread that I now can not find,saying everything should be mounted on the tunnel for best results.

[expresscraft]

I have Chis at das boata props doing a set of L and R x457 props,I still hope someone will respond to the question of the motors and batteries on the tunnel or in the sponsons, seams like they should be low in the sponsons, except I thought I saw a thread saying that was not the case. I do want the motors on the tunnel to allow me to use standard struts with a center rudder, I think the props being closer together will allow the boat to turn better then if they are on scale drives 17" apart.

[jcald2000]

Motor on the tunnels are going to raise your CG very high, that why most every one runs the motors and batteries in the sponsons with the esc's on the tunnel. Corners MUCH better that way.
The stanard struts do give you more adjustabilty.

[Xcesive8]

If you wanna run motors up on the tunnel to get the desired exit point thru the transom so you can run struts and have props closer together, Mount motors up top, but put the batterys and esc in the tunnel to help combat the extra weight up top..
Make sure you make up some batterys trays to secure batts well, last thing you want is a batt going through the hatch.

[expresscraft]

the main reason I am asking is because it makes sense to keep the cg low, but I was sure I saw a thread where they where saying there is a problem with mounting the batteries in the sponsons,I know that a low cg is good, but I also know that sometimes things that sound good make very little difference,we run gas engines on the tunnels all the time with no bad effects, I am going to mount the electric motors on the tunnel 5"apart to keep my struts close for good turning, its more a question on the batteries,I would think low in the sponsons would be the way to go, except for that thread I saw that said no. I do not want to sound stupid, I for one can not see anything wrong with mounting the batteries in the sponsons.I just thought I read that somewhere.That it's a problem.

[srislash]

I run smaller hulls but mount motors and batteries in the sponsons,only my ESC's and radio gear is on the tunnel. On a larger hull you should have room to put everything in the sponsons. Though I do get you're idea about the central location of props allowing for better turning.Most of you're weight will be in the batteries so having them in the sponsons with the ESC's should be best.And should give you the ability to keep wires power short.
Shawn

[sundog]

If you are using flex cables you can mount the motors low in the sponsons and still use the strut arrangement you described. Just a matter of how the stuffing tubes are bent. It is not unheard of for stuffing tubes/flex cables to have two bends in them. Just food for thought. I'm also a fan of keeping the cg low in the hull for stability in turns, and motors can be quite heavy.

[expresscraft]

ok so I am making some progress now, I made a set of carbon rails,Chris sent me a set of motor mounts to use as guides, they where not perfect mounts for this motor and he sent them free and only as a service to me,the rear mount as you can see was over sized, I used a piece of radiator hose and trimmed it down to fit nice and take up the slack, The mounts where also meant for 5" rails,That was going to put my rails on the outside edge of the tunnel which is not what I wanted, so I am cutting them down, they are at 4" now. I might go a little more but 4" will probably work.

[expresscraft]

A few more pics,should start to come together pretty fast now.