Hi this iss a question i cant asere. my mates hull a 60inch mono hull.
his boat becomes verry un seady and unpredictable at speed it rocks side to side at speed. and also realy seems to track when cornering wants to keep going around . the main problem is the boat gose good till about half speed but as soon as you open up the throtal and it incresses speed the hull realy seems to run on the front of the keel and rocks side to side and gests verry loose in the rear and realy unpredictable .
the engine mounts were put in buy the manufator and is set up as thay sugested . the only diffrence is thay only runn this with a stock motor and only runn it at say 70klm (not miles), and we are running a mod omtor . it seems like the hull once we open it up over that speed gets realy out of control and totaly unsteady when running in a strat run . if boat is run in a ark /slit turn it seems to runn a little better but as speed increases it gets verry unpredictable . and this stupid rocking for side to side at speed or even half throtal.
we have tryed difrent adjusments added trimtabs , we are useing a abc 2814-3 that was ment to help keep the transum from lifting but it still seems to run on the keel. the hull has a stepped hull and verry deep keel at the bow of the boat with 2 rather large steps from half way back. would these steps be creating to much lift in the rear making boat runn on the bow more and thus making the boat seem lose at speed.

enny idears .
as he and i have given up tryin to resolve it .
also when turning and comming of throtal the hull just wants to ceep tracking into a sharp corner .like it runss on the deep keel at the bow rather then the transum....

enny one want a expensive:silly: boat cheep.

This may sound odd Try adding some weight to the hull.
A good way to fool with this is simple water bottles on the outside of rails either side of engine.
You can more them forward and back changing the CG, but what it sounds like is the LIFT of hull is excessive for the weight and speed your running at.

Scott wrote:
scott you are thinking just what i have been thinking . i was goin to add weith to the hull at the rear . and as you say the speed yes when running at say stock motor speed say or half throtal goes ok sort of . but give it a boot full and it realy is not good ,haha .
i do beleave the steps are way to large and for the weith in the hull it creats way to much lift in the rear.and has a keel on it the front looks more like a yaght or a deep sea cruser.

well my frend has disided to bench the boat and . is awaiting the arival of a 56 apache same as i run. as we realy cant get oner how bad this other boat runs. i gess this boat is just a crusser and not one for running at speed or it might be sutted for a much heaver motor set up . or running in large chop at half pace.
ill sugest that we mix up some concreet and add to the hull. haha....

might one day try the lead weits or the water bottles...

cheers..

I think Scott has the right idea with one exception. I would think you would want the extra weight as low as possible in the boat, so outside the stringers would not be the right place. I would use flat fishing sinkets held in with a small amount of rubber cement. By using rubber cement, you can easily add or remove the the weights. I would start with 1 pound ( 4each 4 ounce weights 2 either side of the shaft ) right bebind the engine. Good Luck.

Steve Seebold wrote:
Steve is correct ONCE you have a clue how much and what location (CG) is actually required to get hull settled down.
* Thus the wording used in my original post ... A good way to fool with this is simple water bottles on the outside of rails

Did this start out as one of the ready to run Bat Boats? I don't know the real name but they have some Batmobile fins on the sides near the back.

Ed Sidders wrote:
haha , no mate this is not one of those china cheep boats . just a large mono. that needs sorting out . but will be put on the chelf for a whylle as it looks good but just not what he wanted ...

those bat looking boats are shall i say bat ugly... even the full size ones of them ar ugly as....haha//

Check the hull for a hook as well, we had a repaired mono that did what you are talking about, narrowed it down to a hook in the hull. At low speed it ran OK, but as the speed came up the boat would stick to the water rock side to side then the prop would try to surface due to loading and the boat would get very squirrely.
Just another thing to check.

mike sr

hi there no the hull dosent have enny hook . but if you run a strate edge under the hull from 2/3 back where the step is to the transum there is nearly one cm drop . also the two steps in the hull are as nearly deep as a thum about 3/4 of a inch deep and about 1-1/2 long. thay realy seem way to big for this type of hull . so you have a normal but still deep keel towords the bow of the boat and the these to large steps . the hull is 17inch wide also so fearly wide and with that extra lift in the rear just seems to make it verry unstable . unless you use a stock motor for crusing around or running half pace in realy ruff water . or and a tone of ballast , that realy seems a wast of time . i recon the hull would be great if it dident have these large cut out steeps in the hull and such a deep keel towords the bow more like a motor yacht.
....put it this way you can stick your thum into the steps there that big. i say this hull is made realy for just crusing around with stock motors or heave twin set up.
not to worry this hull is now beeing used as a decoration .and will be sold latter on . and awaiting a new diffrent tryed and trusted hull to fit out for him....