Help with cougar cub modifying

Hi guys ive got a cougar cub that im looking to mess with. I know a bunch of you will say dont bother and just get a new boat but my hobby is messing with stuff and trying to make them better.
so the boat in question is a cougar cub 10foot, it was powered with a merc 25hp (Stock) but i just picked up a lil force 50hp for nothing and decided im going to chuck it on. But there is a few performance problems that it had already with the 25 which will now be worse with the 50hp.
The hole shot on these is terrible, It just wants to mono all day and you pretty much have to stand on the deck so ive played with a few ideas and just wondering if you guys think it will work.

DONT LAUGH LOL


Reason for this is i like to take the little boat out cause a day on the water in this only cost $30 in fuel and it can ski with the 25 but its not legal as its only a 2 seater. so with these modifications i can make it a 3 seater and maybe improve performance at same time.

 

or would this work better???

 

Your hole shot will be pretty dramatic with the 50HP engine. Get the trim angle right and hold on when you advance the throttle. The difference in weight of the engines may become a problem because the transom and aft sections of the boat can support a limited amount of weight.

Be sure that your insurance premiums are up to date and then have fun.

 

furious cub - your Cougar Cub is a nice little tunnel boat. 50hp might be lot's for it, so check out your balance situation, particularly with your planned added passenger/payload. You should be able to make the hull perform well, with proper modifications for the new hp.

 

jim boat just the man i wanted to see reply to this.

Im thinking of also adding some flotation pods to help with hole shot and also supporting the added weight of the motor and thinking to build up the cabin sides an extra couple inches to stop backwash hitting on shutdown.

once the transom and deck is redone i plan to flip her over and blueprint the hull bottom and maybe add some choke to the tunnel (opinions)?

And messabout good thing the new motor has trim control the static trim was such a killer for performance but i still managed to get a 130kg guy up on a kneeboard.

 

furious cub - what do you mean by the 'floatation pods' and 'choke' to tunnel? This boat's performance will be very sensitive to weight. Performance can be predicted, though.

 

Jimboat.

I mean pods on the back with foam inside them to help me plane out quicker.
And i had the wrong name for the (choke) venturi throat i believe is the correct name.
Its where the tunnel slightly comes in towards the transom to increase lift.

These will both be quick removal mods so if they dont work ill just remove them.

 

furious cub - by "pods", do you mean an extension to the sponsons aft of the transom? As for your "venturi throat" tunnel configuration, if you mean that the inside edge of each sponson "comes in" (not fore/aft straight), then i would not recommend this approach. But maybe i don't understand your idea. Give me a call or PM or email me, if you want to discuss your mod's and performance expectations.

 

Furious cub: why not add a small set of tabs to the back of the boat that will aid in initial planning and help with your hole shot on popping up a skier.

I just started an idea on wanting to build and maybe produce 16-18' mini-cats of the LARGER offshore boats like what cougar did with you cub and a few other companies during the 80's.

I love the fact that you have an original cougar cub. I had a Baja skat cat with a 35 Merc and it flew. I know the planning problems on that somebody was hanging on to get the darn thing to plane but once up it was the ****!!!

Here's a pic of the boat that I want to upscale to royghly 17' a MHZ Mystic

 

4Fx i could add tabs but i think the pod/extension would be a safer idea. As they will help hold the transom up higher when stationary/on shutdown. Ive also heard that they help hole shot dramatically.
They will be angled upwards so once planing they shouldnt touch the water at all.

Jim boat yes i mean an extension to each sponson. So i can step on them as its so hard to get on the boat if a skier comes off. Like i said above i will angle them upwards so they wont be in contact while on a plane.
As for venturi throat ive decided lifting strakes on the inside of the tunnel would be a better option.
And i would love to call but im from Australia. And if i called i can foresee my bill coming in upwards of 200$ cause when im learning i can talk for hours.

Ill draw up some designs so u can see what i mean.
None of them will be put into place untill after i redo transom to hold the power and a float/plane test so i can get the WL

 

4Fx. That boat looks sick do u have a pic of the planing surface?
After im done with these boats. Cougar cub/stiletto.

I will have a shot at designing a boat i just want to learn what works/dosnt on some existing hulls first.

 

Love those cougar cubs. Back in the mid 80's I worked on a research project for the US Coat Guard trying to find a better way to determine horsepower for outboard boats. (didn't work out well) One of the boats we tested was a cougar cub with a 35 hp merc. That thing was a lot of fun, but at 35 hp and full throttle it was really squirrely. The only guy who could handle it was a professional race boat driver.

There is a reason why, in the USA those little thrill craft are limited to the amount of hp they can handle while being run through a specified test course, and 40 hp is the max allowed by law here. There is also a good reason they were called "thrill" craft.

Anyway I think 50 hp may be way too much, and way too heavy. A 50 Hp weighs almost 100 pounds more than a 25 so you may have a serious problem supporting the weight, even if you make the boat several feet longer.

 

My 50hp motor weighs 110lb i have cruised around with 4 people squished in the boat and the boat had no problem supporting the weight. It may be a different story at full speed but there is another guy whos cougar cub does 53mph with a 50hp.

 

Update.
So ive finally come up with a practical way to design the interior and add some flotation.
So here it is tell me what you think

 

Ok so now ive started to get to work after a while of planing.
So the last couple of days ive started to gut the interior and remove all floatation foam which was surprisingly quite dry in most areas except on the tunnel.
And ive also ripped out my old transom which was a death trap waiting to happen...
See pics.