samuelmerry

My bristol/Bath chat was going off topic so i have started this new one.
here are the pics i have posted so far....

samuelmerry

ran for the first time today!!! went well!!!!
need to make a wedge to fit under ther rudder mount as they are kicked under the boat due to the angle of the transom and are pulling the hull under in the turns. also tourquing over in turns, probably worsened by the rudder issue.

martno1fan

Might be best also to ditch the double rudders and go with a standard single offset one,less weight less drag also.Sounds like your getting prop walk veering to the right? if so a sharpened balanced prop will help how sharp is yours.As regards the wedge it doesnt take much at all ive slipped a piece of ali bar under the bottom of the bracket drilled for the bolts to go through before now and that seems to work.
Mart

samuelmerry

it is not veering to the right, just pitching to far over when turning left. have been talking to Phil Locke who races in OMRA series and he seems to think that it may all be due to the rudder angle...

martno1fan

If its running straight and not prop walking then it might be the rudder angle as angling them in will lower the bow in turns but also your turn fins may also be the problem where theyre situated.You will also find this boat runs much better when its choppy than if its flat calm in fact its amazing what difference it makes .
Mart
heres a few videos of others who have built this boat.

flat calm conditions
http://www.youtube.com/user/wayneuk#p/u/9/5qQviWVdD2Q

Isle of wight harbour red hull
http://www.youtube.com/user/bertybas...24/Ekeu06FST-k

same place black hull
slightly rougher conditions
http://www.youtube.com/user/bertybas.../5/_4mMHkhO-5c

same day trimmed in better
http://www.youtube.com/user/bertybas.../2/gS3HpJfiKvI

samuelmerry

once i have the rudders shimmed square then i will try with and without turn fins, with twin rudders i may not even need them. i think with the position they are in i could easily switch them for some trim tabs for some additional tunability.....

martno1fan

You should find once you get the rudders sorted you wont need trim tabs,turn fins are great for keeping her smoother in turns as she can be liveley in a turn so also make sure you dont have too much rudder throw .Once you find the best settings shes a joy to run and makes a great sports boat in any conditions as you can see in the vids.
Mart

samuelmerry

thanks again for the info, possibly some of the best aftersales ever, even when i bought the hull over a year ago!!!

martno1fan

Thanks for that Samuel,means a lot to me .
I allways try to help if i can,keep us posted on your progress and above all have fun.
Mart

samuelmerry

You dont happen to know a precise figure for the angle of the transom on the hull (see picture) do you? that way a can get the machine shop where i work to make a very nice spacer for me....

samuelmerry

Update....
I have added a wedge spacer to the rudder mount and also added spacers to the turn fins to bring them closer to the chines....
hopefully these mods will help with turning performance.
also, during the first running i was using a tank of water for ballast, which has now been replaced with stick on wheel weights.

samuelmerry

pictres of above...

samuelmerry

First vid,

http://www.youtube.com/watch?v=RNVnbdxzMaQ
its a bit short but my brother did not have much space on his phone, need to sort some better equipment..

am getting some touquing over in a straight line, any ideas? I am thinking it is the prop, currently running an x470 and not sure where to go from there?

martno1fan

Hi Samuel,
is the prop sharp and balanced?,next question is did you offset it to the right a bit ?1/8-1/4 is usual.Both these things will help eliminate prop walk which causes the boat to veer to the right which sounds like whats happening.
Mart

samuelmerry

Hi Mart,
The prop is sharp and balanced and i am not getting prop walk. The boat is leaning over to the right as the revs increase, if this is normal then i will just have to get used to it! this is my first gas boat after all so do not have that much experience......

on another note I did some runs without turn fins and turnng was a lot more controlable without them, maybe i dont need turn fins with the twin rudder setup?

samuelmerry

Had a second look at my prop, looks like it is not as sharp as it could be, it also looks like i have picked up a little damage on the leading edges, this is problably because i have had it for so long whilst building the boat and to be truthful i have no stored it in perfect conditions.
I have never tried to sharpen/balance props myself, is it a simple process? i have read plenty on it but have never fancied doing it....

samuelmerry

forgot to mention it is a fairly cheap (£16ish) aluminium prop, so i could always go for an upgrade....

Dreamin Hemi

Read through these pages...lots of information.

www.rcuniverse.com/forum/m_3120686/tm.htm

samuelmerry

going to have a go at re-sharpening it, have also ordered a new prop in case i mess it up!!!

samuelmerry

update,
during the running in which the video was made the collet connecting the prop shaft came loose, have just taken it apart to check it and a few of the outer strands of the flexi shaft have broken where the friction cut them, new flex shaft methinks.

i think i did'nt tighten it up enough, i will know for the future, at least i didn't lose the prop, drive dog etc...

martno1fan

That may be so m8 ,ive been running my navaho this week and to be honest it handles great and no fins or tabs at all,everyone seems to just put them on without even trying a boat without them.I allways try boats without either and see whats what before i install anything that may not be needed .If you boats just leaning over due to torque of the engine you can offset that by installing some weight on the left somewhere near the engine ,some lead weights or similar will do,try it first before sticking them in permenantly.
Mart