What Motor Would you Recommend

[k225]

:confused: In a weak moment I bid on a boat and won at an auction at our last club meeting. I am now the proud owner of a 32 inch scratch built boat with a 11 1/2 inch beam. It was well built many years ago by a hobbist I respect in the club who is now 83 and has decided to retire from the hobby.
It is a glassed plywood hull with twin 2 inch brass props, and has a belt drive 1:1.5 reduction. It is powered by two Robbe EF 76 II 6 - 8 v motors. The hull is certainly not a light weight.
The first time out I ran it on a 6v 5 amp battery, initially it ran well, however I found the bow had a tendancy to dig in and while the speed was probably scale I would like to speed her up. I could add another batterry of the same size to give me 6v and 10 amp.
Any suggestions from the group on what motors might be able to give her a better burst of speed. I'd like to keep the belt drive and two inch props.
Also I suspect the bow digs in because of the angle of the prop shafts would adding weight to the rear help?

[Ron Olson]

You do need to move some weight around if you can. As you said, it's heavy so you don't want to add any more weight to it. Whatever weight that you can get rearward will help with speed and handling. You should be able to get some hotter motors for it, maybe upgrade to larger Graupners.

[k225]

Thanks Ron I have to agree, would the Speed 600 be adequate or do you think I should go bigger?

[k225]

I've tried the Speed 600 combo with the weight shifted more to the stern and it has shown a marked improvement in performance. I am running the dual motors through a single Proboat ESC, it heats up quickly and shuts out suggesting there is too much current draw. I would suspect this is due to the large props, my options would appear to be go a smaller prop, or possibly water cool the ESC?

[Climate]

If your ESC is shutting down due to thermal or current overload, it is too small.
Water-cooling will help slightly with the heat, but do nothing for the current carrying capacity.
The Proboat ESC's are pretty low current, high resistance units. Try smaller props. You may find they work better as they let the motor unwind and reduce the current they draw.

Peter R.
www.climatemodels.com

[k225]

Thanks Guys
I remotored her with two 540's from an airpump (cost $8.99) which included the 5 :1 gearing. I am using a 12 v 7 amp battery with a homemade single ESC driving both motors. . This combo with the existing props doesn't make it a speed boat but she does have a realistic speed on the water. Nice solid well handling boat.
The color scheme was inspired by the gentleman who I bought it from since he was an WWII RCAF vetran the lines reminded me of the RCAF Marine section crafts from the 60's, the plus was it added a bit of colour. There was a real M537 the RCAF Arrow which was actually a craft used in WWII to service radar stations and coastal watch stations on the Pacific Coast.
The advice from the board and the fellows in my local club helped me out. She's nothing fancy but a reliable fun boat for a first time effort and as has proved a valuable learning tool.

[Ghost 2501]

use an electronise speed controler, not for reasons of quality, as they are as good as any other on the market, BUT, they are quite heavy, place one of them in the vessel amid ships, and transfer some of the heavier items aft.

Part of the reason that I think that you are digging in at the front, is because of the weight of the cabin. so move as much as possible aft, so that the boat sits slightly stern down, that way she will rise easier at lower speeds

[jmolwitz]

Ditch the lead acid battery , to heavy. Try a nimh pack of the same voltage and watch as your boat lifts out of the water and goes . Better yet try lithium batterys if you have some . A lighter boat will pop up much easier. How much does your battery weigh? A 10 cell 3000mah battery weighs 23 oz . 1lb extra in my 24" work boat means it runs like a workboat get rid of the weight and she flies .