vamp131

Hi im running a 61 having problems as usual lol

okay i have a 11 by 8 prop on my boat I have reinforced my engine mount

nice bits of steel not move now! Or so I thought still cut into my hull right thro fibre glass resin too!

now i have a 10 by 7 3 blade prop that rick gave me but boat is not as fast as a 11by8 prop

so what is the difference in say a 11by 8 to an 11 by 7 prop or an 11 by 6 prop would like use a 10"prop but the 10 by 8 i have the engine over revs and top speed down as well I look forward to your reply's kind regards Stewart ps my last run went fantastic 6 full tanks of fuel came home then noticed that the prop had cut thro the hull again at least i didn't have to walk in the water to get it back lol making another air boat tested it in the bath to make sure it sat okay it did at the bottom too heavy lol going to try make it lighter put my Irvine engine into it the ripmax one way to heavy lol

here is the boat with the 11by 8 http://www.youtube.com/watch?v=tEmBp...e=user&search=

DONS BOAT WORKS

My Feedback: (3)

I think your engine mount is flexing.
Make the pylons wider at the bottom, and move them forward.
Mount the engine on the pylons.

Don M.

playtime56

My Feedback: (1)

Could also make a bracket pair 1/4" to 3/8" taller. Or 7 to 10 mm

89ram

after reinforcing the mounts, you could also make a shallow groove for extra prop room on the deck if necessary.

vamp131

Hi thats a great idea got a brand new prop today the only problem is the top of the hull is made with very thin wood i cannot get in under it to make a hole for it !! see how my reinforcing works 1st thank you got a 11" by 7 prop give that a go

vamp131

Thank you for your thought the problem is it is a wooden boat and i cannot change the place where the engine mounts are the metal i have put on should stop it flexing the plastic engine mount is the only part that has a bit of flexing just the way the boat was designed hopefully the new metal will suport the engine okay took it out tonight for a test run but forgot to bring glow start test it at the weekend thank you for your time and the drawings kind regards stewart

TERBObob

My Feedback: (21)

I think that the metal that you have for the engine mount is NOT enought strength for the motor mounted up front like that . Meaning , if you took the prop of the engine , and move it up or down , it should NOT move . I think your metal is not firm enough .
Just curious as to why you did not use the four mounting holes in the base of the engine , rather than the backplate mount , as you did ?

vamp131

Hi the new mounts I made worked a treat the new 11 by 7 prop made it go like a bat out of hell but could not control it too well did a nice flip and turned upside down middle of the water

next time i took it out went too near the bank propeller snapped in two so got a 11 by8 a wee bit slower but i can control it lol i get a spare 11 by 7 keep it till i get a big bit of water try it when the summer comes hopefully soon never seen so much rain here well it is Scotland lol