ideal cg point for mono??

[wayne middlemiss]

im setting up a new boat from my own molds to which i purchased 46'' kingkcraft molds.

would i be correct @ 28%-30% from transom . what are your thoughts.

 

[Ian Inverarity]

27 to 28 percent was pretty standard for the Kingy's.

 

[wayne middlemiss]

thanks ian so my thoughts are fairly right. also im thinking of using surface drive units instead of a strut. are they a good option, and im thinking of the shaft line to be higher up on the transom instead of being on the keel line 3-16/ 1/4'' higher.

 

[mark voorhies]

thanks ian so my thoughts are fairly right. also im thinking of using surface drive units instead of a strut. are they a good option, and im thinking of the shaft line to be higher up on the transom instead of being on the keel line 3-16/ 1/4'' higher.

Wayne, you have a good perspective on a surface drive mono hull with the shaft coming out at 3/16th above keel on center,

on the last mono I set up, which was a Cal-Craft, with a strut, and set at 1.5 negative degrees. CG was 34% of hull from

transom, the more power you have , the more % from transom, to keep the hull level. Don't know about Kingcraft hulls,

just a note on what I have done in the past.This is for a heat race boat set-up or rough water.

 

[Rickard Andersson]

My thoughts: +30% but,,,,,,,

What kind of Engine aim to use?

Pics of hull, (bottom) would help! (Shape, strakes)

Rickard

 

[Ian Inverarity]

thanks ian so my thoughts are fairly right. also im thinking of using surface drive units instead of a strut. are they a good option, and im thinking of the shaft line to be higher up on the transom instead of being on the keel line 3-16/ 1/4'' higher.

Wayne,

I cant really help there, I always used struts rather than the stinger type drives, but always surface drive. It is so long since I ran one I dont know about the strut depth, make it adjustable! The Kingcraft is too pointy at the front for more modern CG settings.

 

[dwilfong]

30 to 33% is the best setup. use a strut with a oval hole in the transom this will make setting up with different props easy.

On bigger boats raising the strut and using larger props works good.

A prop that will not run low to the keel will come alive if you raise it just running on the tips.

You will pull more pitch and run faster.

Make sure when you put the radio box in the boat you leave room to raise the strut and tube up high.

Put the eng in flat and as low as can go. this way it is a strait shot to the strut no bend in the tube.

Use a Tbar in the front.

That is why thy call them surface drive. Run it on top of the water not dragging it thew it.

Don't be afraid of running a high lift prop. With the right strut angle it will balance out the boat.

You know it is right when you launch the boat it takes time to get up. The prop will not hook up right off the bat.

Once you get up on it, it is good to go. when you mill it will spool up then bite giving a great hole shot.

This is different than most will recommend. But then again that is what it is. works for me.

David

 

[wayne middlemiss]

building 2 boats , one is being fitted with picco 90 pumper its nib, second will be done with 260 zenoha,

ian i am going to give the surface drive units a go they look user friendly to setup nothing to loose i suppose.

its been long time since i have personaly had a mono , something different for me.

mark im aiming for heat race setup on them ,straights are the easy part, corners are the bad part, just need a good setup all round for good package.

rickard they are simalar to the cal craft style hull if that helps you any , typical oval mono i suppose.

 

[wayne middlemiss]

30 to 33% is the best setup. use a strut with a oval hole in the transom this will make setting up with different props easy.

On bigger boats raising the strut and using larger props works good.

A prop that will not run low to the keel will come alive if you raise it just running on the tips.

You will pull more pitch and run faster.

Make sure when you put the radio box in the boat you leave room to raise the strut and tube up high.

Put the eng in flat and as low as can go. this way it is a strait shot to the strut no bend in the tube.

Use a Tbar in the front.

That is why thy call them surface drive. Run it on top of the water not dragging it thew it.

Don't be afraid of running a high lift prop. With the right strut angle it will balance out the boat.

You know it is right when you launch the boat it takes time to get up. The prop will not hook up right off the bat.

Once you get up on it, it is good to go. when you mill it will spool up then bite giving a great hole shot.

This is different than most will recommend. But then again that is what it is. works for me.

David

thanks david as you have mentioned are the aim but im not real sure about the suface drive unit or spd as refered to as opposed to strut and braket mounts.

 

[Tim_Duggan]

Hi Wayne,

I still have my Kingy that Dale Heiler set-up. photo attached of the stuffing tube position. I believe it was quite critical. It's offset about 3mm off centre and the bottom of the tube is about 7mm up from the bottom.

https://www.intlwaters.com/gallery/displayimage.php?pid=18078&fullsize=1 I can take more pics if you need them, just let me know. It's just here collecting dust!

I (really) vaguely recall 28% as being the CG number but the engine mount and engine have been removed so I can't confirm.

 

[wayne middlemiss]

thanks tim i should be right with it all .......... im juggling around with engine rails to get it up front a bit more on the zenoha setup before they get fixed in the hull. dale never said much about setup ,but dont matter realy.

 

[John Finch]

Just a suggestion.......31.5 percent cg with bracket strut 5/16ths center of shaft to keel and 1/4 inch right of centerline. Put rudder 2.5 inches to right of strut. Go have fun!

 

[Tim_Duggan]

thanks tim i should be right with it all .......... im juggling around with engine rails to get it up front a bit more on the zenoha setup before they get fixed in the hull. dale never said much about setup ,but dont matter realy.

No worries Wayne. If I recall correctly - when I asked Mike Gillman about how far forward the Zenoah should go I think he said get it as close to the deck opening as possible but still able to grab the pull start. I got a 231 and mount to put in to mine after taking the K90 out, but never got around to it - mono's just don't do it for me I'm afraid. Not enough sponsons I suppose....

 

[wayne middlemiss]

thank you for your input john im not sure i would get 31.5 % cg deck gets in the way a bit.

 

[wayne middlemiss]

just a bit of difference for me tim on the mono as i have the mold other wise would not even thought of one, its true what they say tim if want to go racing get a hydro mono's are for fish'n lol. i might use the idea of ballast tanks like ski race boats use in conjunction with trim tabs with out adding dead weight .????