2009 futura mk 2 hd with 50hp honda efi?

[mcpower5000]

Hi all,

I am new to this, I just purchased a 09 Zodiac futura mk2 hd, and planning on powering it with a 50 hp EFI honda outboard. Will I be overpowering the boat by using the maximun allowed power on the capacity plate. I am torn between getting the 40hp or the 50 hp, they both weigh 205 lbs dry, so I think that I would be better off spending the extra $500 to get the 50 hp. Any input would be much appreciated.

 

[nobrainsd]

Re: 2009 futura mk 2 hd with 50hp honda efi?

If the weight is the same and the price isn't a big issue, go with as much horsepower as you can. If you do a search you will see that a lot of people have issues with 4 strokes and weight because they are running older style zodiacs with the smaller tubes. Your boat is designed for a 4 stroke weight. I run a 40hp 2 stroke on an older Futura MK2. Zips along at 30 mph with a full load. I would be stoked to run a 50 hp on it. It is important to realize that you aren't going to get a lot more top end speed from that extra hp. A soft bottom hull, even with speed tubes, isn't exactly the most efficient planing surface. Drag builds up quickly as the speed goes up. You'll get a little more top end speed, but the extra horsepower will really help your hole shot if you tow riders. Nice to run at less than full throttle for the same speed too, less taxing on the outboard. The Futura can definitely handle the rated power.

 

[mcpower5000]

Re: 2009 futura mk 2 hd with 50hp honda efi?

Thanks for the info, I decided to get the 50 hp honda 4 stroke, it weighs 205 lbs, I took it out on the lake the other day and with 4 people aboard I got it up to 30 mph. I had a lot of splashing off of the motor, so I looked into the height of the anticav plate compared to my keel and it looks to be 2 inches below the keel. Where do you recommend I place the anticav plate, even with the lowest part of the keel or a bit above?

 

[nobrainsd]

Re: 2009 futura mk 2 hd with 50hp honda efi?

The general rule of thumb is to have the anti ventilation plate even with the keel, but on Zodiacs with speed tubes it is usually better to be set up an inch below the keel. But motor mount height isn't the only part of this equation. How you have the outboard trimmed will make a big difference in the splashing you get. When I first purchased my futura I was using the tilt trim to help the boat get up on a plane and decrease bow rise. The engine would be well forward to get the initial effect I desired and then had to be adjusted when the boat planed. Without adjusting the outboard I got a lot of splashing when on a plane. The water flow was hitting the prop, ventilation plate and shaft at a less than efficient angle. I installed Smart tabs on my mk2 futura so I don't have to adjust the trim of the outboard to keep the bow down. I have the trim set where the outboard is powering the vessel along and the motor is parallel to the flow of the water. Very efficient and generates minimal splashing. There is some spray coming up, but it isn't significant and it isn't coming into the boat. Without the trim tabs my outboard would often be tilted off the plane of water flow. Kept my bow down, but didn't help the flow of water past my prop and shaft. You should also look down at the anti ventilation plate while under way. The plate should be right at the surface of the flow of water off your hull. If it is above that flow or below it is not optimal.

 

[mcpower5000]

Re: 2009 futura mk 2 hd with 50hp honda efi?

I tried the boat out with the a/c plate even with the keel, seems to get up to plane much faster, but feels like it ventilated if i accelerate it to fast. Could you post a pic on how you mounted your trim tabes, I can see how It would make things a bit easier without having to adjust the trim after getting on plane.
Is it ok for me to store the boat for long periods(1 month or more) of time on a trailer fully inflated? or should I be deflating some?
Thanks

 

[nobrainsd]

Re: 2009 futura mk 2 hd with 50hp honda efi?

That's why I recommended have your anti ventilation plate 1 inch below the lowest part of your transom on your futura. It's not the anti cavitation plate. The anti ventilation plate on my futura rides nicely on top of the depression in the water off my transom when set up at 1 inch below the keel dip.

You may also find that stock props are not the best solution on an inflatable boat, outboards are set up for heavier displacement hulls. Mine was pretty close, but I changed pitch to get the right WOT rpm. Went with a four bladed adjustable composite prop.

Having the right trim sure does help. Part of that is trying to move some weight forward. Gas tanks, outboards, batteries and people at the rear of the boat are not an balanced load. Trim tabs sure do help. If you use the search function on this forum you will find pics and posts. I'll include a few anyways, but there is a lot of info available with a search.

Storing your boat partially inflated is the best option. Leaving it fully inflated is a mistake. The pressure in the tubes varies widely with temp and you need to have headroom for expansion if the conditions in storage change.

tab from above (even with a stainless tab an anode is required in salt water

Installation with optional pulley mechanism to raise tab

 

[mcpower5000]

Re: 2009 futura mk 2 hd with 50hp honda efi?

thank you for the information, I just took the boat out after adjusting the height of the motor. I checked out the anti ventilation plate while on plane, the plate is just under the surface of the water when the trim is level. I have even more splashing now then when I had the motor 1/2 inch lower, so I think that if i raise it 1/2 inch more I should be in the right ball park. I think that the prop is not ideal, like you said made for a heavier hull boat. The prop spins out very easy, I have to throttle up very slowly to keep it from over revving. What do you think of my issues, am I on the right track?
Thanks

 

[nobrainsd]

Re: 2009 futura mk 2 hd with 50hp honda efi?

Well, A little more information would be good. At WOT what is your rpm? Part of deciding whether you have the right prop set up is looking at how it fits the specs for your outboard. I guess the second question would be how much splashing you are actually getting. A light amount isn't worth worrying about. If your outboard is not giving you proper thrust and is truly cavitating then you do need to address the issue. The distribution of weight is the most overlooked aspect of performance in inflatables. In my experience the angle of the outboard to the transom has the most effect on splashing. Cavitation is height ,angle and prop dependent. Do you have a remote control outboard? If all the weight is at the rear you may have to ramp up on to a plane. In other words full throttle hole shots may be an issue.