tbaysal2000

Has anyone experience with stepped hulls for fairly wavy conditions at sea or big lake?

I just opened another thread on MHZ Colibri 52" but decided that this should be another topic. I tried search but so many replies confused me so if there was already a healthy discussion, please direct me with a link.

Looking at the pictures of Colibri, besides being stepped, the bottom is not sharp but flat like one inch. Is this same for all stepped hulls and any specific reason for this desgin? Would this add better performance at still conditions and disadvantage for wavy as it will not carve into the wave?

Slow Motion

Stepped hulls are designed to airate the water on the running surface, freeing up the hull. There is little advantage when running in chop or wavy water, because the hull isn't stuck down anyway. The 1 " surface of the keel is called a ride pad. It's designed to get the hull up on top of the water, just like a ski. NOT what you want for rougher water. They can be fast, but can also be very unstable.

tbaysal2000

In this case it has to be my spare boat for the very still times of the water. I wish someone had a built one similar to this to show how to make all the set up with a modified zen. Any chance on this as I think it is not only MHZ making this type of hull. Even the photo from MHZ Usa shows 2 different set ups at the back. Both not familiar to me [&o]

Slow Motion

Many years ago, I scratch built a wood V hull with a 1" ride pad. It was fairly light. With the drive down low, as in the pic of the yellow boat, that thing would ride so high out of the water, that I could hardly find calm enough water to run it on. The point I'm trying to make is, with the ride pad, I think you should run the drive higher than that pic ( C/L of prop shaft 1/2 " from bottom of ride pad ), so the eng. will unload ( higher RPM ), and you will have a little better handling. The rudder I like 2 1/2 " to starboard, and deep enough to turn well to port. If your straight line handling ( high speed ) needed more stability, I would go with two trim tabs mouted fairly close to the ride pad. Keep the bottom surface of the pads about 1/16 " up the transom. Angle the pads down very slightly to stabilize the hull when it's right up on the pad. Those tabs in the pics, are only going to do anything when the hull is already banked a way over ( too late ). Ride pad hulls don't always turn well at full speed, so you will probably need turn fins mouted at the chine line, mounted 90 deg. to the hull bottom.

tbaysal2000

Slowmotion, I would never be able to figure out all that, many thanks [sm=thumbup.gif].

I am short on budget so I am looking to complete my project with parts which boaters don't need. So all part offers to complete this budget are welcome from engine to propeller, all but new or almost new.

For engine and pipe, I wanted a new one and hoped the sikk package was still available at Oneillbrothers but they are out of stock. $370 seemed to be a good price for new parts. I am not going to join a race but hope to have fun and exceed 50 mph. So all hardware offers are wellcome. I am also checking Jim's Dock. You can contact me from my email: [email protected]

More contributions are welcome naturally

martno1fan

im also open to freebies too lolololim also thinking of taking a vacation soon but i dont fancy paying so all donations gratefully received many thanks lololol

tbaysal2000

martno1fan, I am not expecting any parts for free, probably I couldn't express my self. I just wanted to say that I am open to offers but don't expect a guy with deep pockets (or expect a guy with deep but almost empty pockets ).

tbaysal2000

Which type of drive would be best for this type of hull?

- Just a standart drive
- Stinger
- Piranha
- RCM

If there's no impact on performance then I would prefer the cheapest set up. But as this hull is confirmed to be fast but unstable, besides the trim tabs and fins, can the drive choice be of help for stability.

Ultimate48

My Feedback: (1)

The RCM drive " fourth pic " will slow the boat down some, that drive is for a scale look!

so if you looking for speed the " first pic " would be your best bet!

fourth pic is my boat and I'm not looking for speed, going for a scale looking boat !

Just my opinion. hope this helps you!

Steve

Slow Motion

I have to agree with Steve, that a Stinger ( 1 st. pic ) or strut drive with extended rudder is the way to go. For the best control and handling, it's very important to have the leading edge of the rudder blade, even with, or slightly behind, the trailing edge of the prop, with the starboard offset as I mentioned above. It's also important to limit your rudder swing ( left and right ) on a high speed hull. So many boats can't make high speed turns because the rudder throw is too severe. The boat ends up hooking, flipping, and swapping ends, instead of carving a nice high speed turn.

martno1fan

just go with a flex cable and a strut set up much cheaper than a stinger too.also that stinger in the first pic blue one isnt a good one its a cheap chinese one i beleive?.heres a cpl of pics of the set up id go for.

yeeharacing

That piranha drive is very cool looking.
Looks like it's pretty heavy though.