Yam F300 vs. Merc Verado 350 vs. 383 MPI

[Kola16]

Considering repowering my boat due to the constant troubles my engine has had. My boat is a 1979 Wellcraft Suncruiser 225, which is the boat in my avatar. The boat is heavy for 22.75 ft. at roughly 5000 lbs. with gear and without main engine or gas. It has a 22° deadrise at the transom without a reverse chine. In other words it takes a little bit to get on plane with the carbed 350 Mercruiser in it. Once it is up it does okay though. Tops out at 41 mph with a 4-blade, but a higher top speed would be fun....

So my question is this...What would you choose, all things considered, if your boat was an offshore fishing boat on the West Coast with the average trip about 100 miles roundtrip? Hole-shot is something to keep in mind with big waves, but other factors play in too. And yes, I realize there is an F350 and a Verado 300, but I am looking at price of the two...

What would be the hole-shot difference between the 3? I'm assuming the 383 with the Bravo III would definitely be the best, but by how much? And what about the F300 vs. Verado 350 for hole-shot?

Specs:
383 MAG @ 3500 RPMs ~11.5 GPH; 1,100 lbs. ------ ~$20,000 (engine and bravo III drive)

Yamaha F300 @ 4500 RPMs ~15.3 GPH; 580 + 200 (bracket) = 780 lbs. --------- ~$30,000

Mercury Verado 350 @ 4500 RPMs ~15 GPH; 670 + 200 (bracket) = 870 lbs. ---- ~$29,000

To me, it looks like the 383 is the clear winner in all aspects minus 400 extra lbs. Any ideas on the top speed or cruising speed though vs. the others? What about reliability on the sterndrive vs. the outboards?

Any other thoughts and opinions are appreciated!

 

[dingbat]

East coast offshore….My 226 Grady White is roughly the same size. A little heavier if anything. Has 154 gallon fuel capacity

Top speed is 35 kts with a 27 kt. cruise. Fuel consumption at cruise is 2 mpg per fuel flow meter.

My run to the fishing grounds is 40-90 miles each way. Average 150 miles per trip. Have gone as far 250 miles in a day.

I also fish a lot of bridge structures which requires instantaneous throttle response when push comes to shove. The Enertia prop I’m running gives me this and more.

Having said all this….I’m thinking of upgrading to a Yamaha F250 (currently 200 Ocean Pro) in the next year or two. Will increase both speed (~45 mph) and range.

Can’t see the need to hang anything bigger than a 250 hp and certainly not interested running a cast iron egg beater in any offshore boat.

 

[Kola16]

East coast offshore….My 226 Grady White is roughly the same size. A little heavier if anything. Has 154 gallon fuel capacity

Top speed is 35 kts with a 27 kt. cruise. Fuel consumption at cruise is 2 mpg per fuel flow meter.

My run to the fishing grounds is 40-90 miles each way. Average 150 miles per trip. Have gone as far 250 miles in a day.

I also fish a lot of bridge structures which requires instantaneous throttle response when push comes to shove. The Enertia prop I’m running gives me this and more.

Having said all this….I’m thinking of upgrading to a Yamaha F250 (currently 200 Ocean Pro) in the next year or two. Will increase both speed (~45 mph) and range.

Can’t see the need to hang anything bigger than a 250 hp and certainly not interested running a cast iron egg beater in any offshore boat.

Hmm maybe I am missing something. I would have better fuel economy, better cruising speed, and better top speed with an I/O, but the I/O is the cast iron egg beater? Can you explain this further?

I am certainly not interested in putting something less than 300 HP on my boat. I love wakeboarding and on rough offshore days there is a lot of coming off and getting back on plane with a boat load of gear, fish, and friends. Right now I have about 260 HP at the prop and would not blink an eye at anything less. I imagine a lot more torque than an F250 too, but outboard manufacturers don't give their torque curves.

 

[Kola16]

I just realized I put the Verado 400 instead of the 350...Whoops...

 

[dingbat]

Hmm maybe I am missing something. I would have better fuel economy, better cruising speed, and better top speed with an I/O, but the I/O is the cast iron egg beater? Can you explain this further?

General rule when comparing I/O to outboard power is a 25% HP advantage to the outboard for weight.

Your 260 HP is comparable to a 195 HP outboard.

You also list the bracket as adding #200 to the motor weight. In reality the bracket adds buoyancy, not weight to the boat.

So now the outboard has a #600 advantage over the I/O. Could run twin 300s at a comparable weight.

The outboard’s weight to HP ratio in this case almost 2:1 Don’t know how you could come to the conclusion that something double the weight for a given HP is faster and more efficient, especially in a boat

The truth of the matter is that I/O has no advantage over an outboard except initial purchase price.

 

[Scott Danforth]

the amount of work and cost to make your boat structurally sound for an outboard would automatically disqualify the outboard.

I would just get a 377 long block and swap over for your existing 350 long block and be back on the water in a weekend and only out $4200

 

[Kola16]

Your 260 HP is comparable to a 195 HP outboard.

Sorry, this is not right. I rented a 22' Hewescraft aluminum boat for a week with a newer F200. WAY lighter boat than mine with an offshore bracket and way less steep of a deadrise. The thing was a dog. Slower than crap. If I stuck that F200 on my boat, it would absolutely suck. My buddy has a F200 on his 21 ft. Striper and my boat is faster. Currently my boat is as fast or faster than most of the other boats on the way to my fishing grounds and I only cruise at 3500 RPMs, and I went down in pitch and added a blade to my prop even. Most of the other boats run 3 blade outboards. Your boat has a 200 HP 2-stroke (even lighter) and my boat is faster, so I am not sure why you are saying my setup is like having a 195 HP outboard I think you are thinking of I/O's HP ratings as being at the crank, but I listed mine as at the prop.

You also list the bracket as adding #200 to the motor weight. In reality the bracket adds buoyancy, not weight to the boat.

So now the outboard has a #600 advantage over the I/O. Could run twin 300s at a comparable weight.

I see what you are trying to say, but this is not correct either. In a boat that is setup for an outboard with the proper offshore bracket, it does add buoyancy. It does also add weight! Weight cannot be ignored for cruising and top speed! F=ma! For my setup; however, it most definitely does add weight and adds NO buoyancy. It adds buoyancy when the boat is not under way, but let's say I put an Armstrong bracket on my boat. As soon as I hit the throttle, the bracket is hanging above the water, since it is not at the baseline of my boat like it is on boats set up for an outboard. Additionally, that weight's center of mass is being added 5.5 ft. further back than an I/O's is, which torques the bow up (1400 ft*lbs. I calculated) versus keeping the bow down, so yes, weight is most definitely a concern. Also, I would be adding fiberglass to my transom.

The outboard’s weight to HP ratio in this case almost 2:1 Don’t know how you could come to the conclusion that something double the weight for a given HP is faster and more efficient, especially in a boat

GPH stands for gallons per hour. Therefore, the LOWER the GPH the better. Between the 383, Verado 350, and F300, the 383 is much more full efficient. I think your're too focused on the HP rating. Remember that boats need a lot of torque, and the easiest way to get torque is from displacement, not high-revving low displacement engines. That is why I have the Verado 350 in my mind and not the Verado 300 since the F300 has much more displacement ie. more torque than the Verado 300.
HP=(Torque x RPMs)/5252
This means your given HP rating is a lot more than what the final sticker says since boats move with torque. So if you have 300 HP, but you are doing that at 6000 RPMs (F300):
300 = (Torque x 6000)/5252 -----> Torque = 263 ft*lbs.

Now let's say you have 300 HP at 4800 RPMs (random 5.7L I/O):
300 = (Torque x 4800)/5252 -----> Torque = 328 ft*lbs.

That is an additional 65 ft*lbs of torque which makes a HUGE difference. That is why all of the cigarette boats had big blocks versus the small blocks. Sure you could get the HP close to the same, but it is the torque that makes the huge difference when it comes to boats.

 

[Kola16]

the amount of work and cost to make your boat structurally sound for an outboard would automatically disqualify the outboard.

I would just get a 377 long block and swap over for your existing 350 long block and be back on the water in a weekend and only out $4200

I'm not worried about the work or the cost. I like working on boats as a hobby and boating is what I spend my money on so just want to get the best option out there. I want to ditch the carb though.

If an outboard is more reliable or the weight savings is that much more noticeable, I would rather spend the money for peace of mind. I don't want to be 60 miles offshore and wish I had bought something else, due to the fact that I am floating dead in the water on my way to Japan (only a joke, I do have a kicker and safety gear).

 

[Scott Danforth]

Both I/O and outboards are prop rated after 1983

You really need to look at torque curves and prop curves. Also, you need to understand the force load path.

Modifying an I/O hull for outboard use is a significant engineering undertaking

 

[Kola16]

Both I/O and outboards are prop rated after 1983

You really need to look at torque curves and prop curves. Also, you need to understand the force load path.

Modifying an I/O hull for outboard use is a significant engineering undertaking

Ya I understand that. I am a mechanical engineer though so I would hope I would be able to figure it out

 

[flyingscott]

how much weight do you think you would actually save? The Verado set up at 870#s doesn't include the extra bracing you need for an Outboard conversion. Not to mention the repairs an a small block Chevy will be significantly cheaper than the Verado. Not to mention the small block will be simpler with no supercharger or fuel injection. And lets not forget that Mercury is already moving away from the Verado platform.

 

[Scott Danforth]

Ya I understand that. I am a mechanical engineer though so I would hope I would be able to figure it out

so am I and I know most of the engineers at Mercruiser (many worked for me at one time) , ilmor, Indmar, PCM, Cummins, CAT, and a bunch that used to be at Volvo, John Deere and Seven marine. I also have connections with many naval architects and engineers at most yacht builders and many boat companies including the guys at marine concepts

I still would not hang an outboard on a boat only designed for an I/O. not worth the time and effort. if this is the path you want to go down, sell what you have, buy a boat with an outboard

if you want to get on the water quick, simply get a long block and be back on the water. if you want to save weight, go with a marinized 6.0 LS with a heat exchanger
or build a 377 with aluminum heads, aluminum exhaust manifold and a heat exchanger. Heck, a big block with aluminum heads and aluminum manifolds with a Bravo will weigh less than the Verado

If you want to spend lots of money and time on modifying a boat vs using it, go ahead.

you already have a boat well past its design life. you may end up doing a transom and stringers once you dive in.

 

[Kola16]

I would have sold this boat a long time ago if I could have. The darned thing has sentimental value. My dad bought it new off the lot with his dad. My dad and I did a full resto on it a 5 or so years ago, which included new stringers and a new transom, so it should be sturdy. My dad used to build fiberglass boats so he knew what he was doing. My dad is gone now so this is what I have left! He loved this boat.

I have thought about the LS route too, but I am unsure about parts for it...I would like aluminum heads and manifolds if I stick with the I/O, which I am probably going to do. I kinda just wanted to see what people preferred and why.