Need Advice on Towing Performance

[mwnitz]

Hi there, boat experts. I am in need of some advice here. I am looking to slightly increase my boat’s performance towing a 3 person tube.

A little background: I have a 2006 Ebbtide 18‘ I/O bowrider. It has a 3.0 L 4 cylinder MerCruiser with an Alpha One stern drive. I’ve owned this boat for almost 16 years and religiously maintained it. This year I replaced the spark plugs, rebuilt the carb (again!), and replaced the fuel filters. I say filters because I installed an additional fuel/water separating filter. She starts fine and purrs like a kitten, so I don’t believe I have anything wrong with the performance of it.

What I do think is I’m trying to do is to get a 4 cylinder to perform like a 6 cylinder. Let me start by saying I know this is unreasonable. But I think there are a couple of things I can do to tweak this boat. I now use the boat differently than I used to. I now have 4 adults and 3 shorties on it, and the shorties absolutely love my 3 person tube. If I had 2 adults on board, she planes off no problem. With 4 she really struggles. I have to catch the conditions just right or she won’t plane off. The wind, the direction, calmer waters… all of that has to be just right in order to plane off.

I really don’t want to buy another boat for the one week a year I go through this. Have you guys seen boat prices lately??? I love my boat and know it like the back of my hand at this point.

Besides lightening the load as much as possible, does anyone have any ideas on just a little more power forward to plane off? She’s real close.

Some of my thoughts:

1. Invest in a stainless steel propeller. I’m thinking it has less flex than aluminum, and might be just the “push” she needs to plane off.

2. Get an adjustable pitch propeller. I had one in the past and experimented with it. After a day of changing the pitch to every setting, I found that the original pitch from the factory was perfect, so I got rid of it. But now is a different situation. I’m thinking a pitch with more torque and less speed would be prudent for this one week while towing. However, this will be a slight pain in the butt as I’ll have to adjust it for cruising. I have to remove the propeller to adjust the pitch, at least if that’s how you still do it.

Edit: I found a #3 on ideas. I found an article on 4 blade stainless steel props instead of 3 blade. The seem like a great idea just for the one week I’m doing this towing.

Does anyone here have any ideas/thoughts/comments on my dilemma? Thanks in advance for your help.

 

[Bondo]

Ayuh,..... Yer askin' alot from a 3.0l motor,....
The best easiest answer for a short term cure is to drop 2" of pitch on the prop for the week yer overloading it,.....
Switching to stainless isn't going to help, without also droppin' the pitch,....

 

[tpenfield]

Agree on the propeller ideas, probably go down a notch in the pitch and maybe go 4 blade. Just be careful with light load that you don't over rev the engine.

As for the future, your 4 cylinder boat might be short-lived if you have a growing family, have more friends on-board, etc.

 

[youmansjason]

Agree on the propeller ideas, especially going to a 4 blade.

Also, make sure all 4 adults aren't sitting in the back of the boat. Have 2 of them sit in the bow, and that should help the boat get on plane.

 

[Scott Danforth]

On my 3.0 powered boat, I needed 3 props. A 19p, a 17p, and a 15p

The 19p was used for long cruise trips with only 2 people. Could get 41mph at 4600 rpm

The 17p was used when there were more people on board or pulling tubes. Would hit redline before 38mph

The 15p was used for skiing, and trolling. Would hit redline by 34, however could have 4 adults on board and a slalom skier in the water. Could also troll at 1.5mph at idle in gear

You need more motor if you only want to use one prop for everything.

Otherwise get a few props with lower pitch

 

[Alumarine]

What prop do you have on now?
What's your rpm at WOT with that prop?

 

[stresspoint]

ever hear the saying " you can put a fur coat on a pig ,but it will still be a pig".
please don't take that the wrong way , this is not at all implying your boat is a pig ,sorry to say its the little baby motor it has that is a pig,
the 4 cylinder 3.0 is not a towing motor, its designed to get a light boat on a plane , set at a cruise speed and lug away for hours whilst giving good fuel economy thats it.

what will happen if you change stuff to make it pull harder it will create reliability issues that you don't want , propping it to gain more RPM will put stresses on crank bearings , drive etc .

my suggestion is you may want to consider running the boat lighter when you are intending to tow heavy loads or lots of people rather than make modifications to a motor that is already straining on its power limit.

propping can be done , however ,keep that 4 banger motor in its specified RPM range and don't lug along with heavy loads or it will break.

 

[JASinIL2006]

Other than the ideas re: the prop, something that might help is something like SmartTabs. My boat isn't underpowered but it would have difficulty holding plane at the lower ranges of tubing speed (18-20 mph). Once I got up to 22-23 mph, it planed fine. Adding SmartTabs force the bow down enough to allow me to stay on plane at 18-19 mph.

 

[QBhoy]

Hi. The hi 5 propeller is absolutely useless at absolutely everything…all apart from the one thing it can do. That is exactly what you are chasing. Ideal for allowing a boat like yours to pull people out the water well. A friend had one on an 18ft maxum 3.0. It was actually amazing how it was able to do just this. Rubbish at anything else. But if that’s just what you want most of the time and don’t care about efficiency or other ability. You’ll be pleasantly surprised. Then you’ll eventually just dig deep and get a boat that’s designed for the job. Like a mastercraft.

 

[ScottinAZ]

ill echo what a few others here have said. For the "one week" you may want to drop a pitch on the prop. just as a tow vehicle works better with different gears than one that just cruises, you need to change pitch some for towing. Its either that, or get all your passengers, and yourself to lay off the desserts a bit, and that isnt likely to go over well.... . As long as you observe the WOT RPM limit, and dont over-rev the engine when not towing, or heavy, you should be fine. Its all controlled by the right hand on the throttle.

 

[stresspoint]

ill echo what a few others here have said. For the "one week" you may want to drop a pitch on the prop. just as a tow vehicle works better with different gears than one that just cruises, you need to change pitch some for towing. Its either that, or get all your passengers, and yourself to lay off the desserts a bit, and that isnt likely to go over well.... . As long as you observe the WOT RPM limit, and dont over-rev the engine when not towing, or heavy, you should be fine. Its all controlled by the right hand on the throttle.

that's funny , but it will be an easy fix to the problem of an under powered boat.

FWIW ,my modded 4.3 in my Maxum has a bit of trouble keeping a plane towing with a boat full ,so i just evict a few passenger's..

 

[Pmt133]

I agree with swapping props... Mine had a 3.0l in it forever. While not the best performer... and loud... it did it. It would do it with a boat full of people, and there were a few outings where while under weight, I really didn't think it would plane. It wasn't happy, but it did it. Every time. I also didn't bother much with swapping props, the boat was heavy enough it didn't make much a difference. My always on it prop was best all around, I went down two inches in a 4 blade and lose everywhere but gained a ton of RPM so I got rid of it.... Wide open was about 33 mph no matter the load, prop, or fuel and it cruised at 23-25. It hardly used any fuel and you always knew when you turned the key you were getting home or going out. Never gave me any problems. I've since repowered to a 4.3l and even with a full boat, it just hops right on plane. (well it did until the engine died) Ultimately if your use drastically changes and you are doing this often, more power is the only long term solution.

 

[Scott06]

Hi there, boat experts. I am in need of some advice here. I am looking to slightly increase my boat’s performance towing a 3 person tube.

A little background: I have a 2006 Ebbtide 18‘ I/O bowrider. It has a 3.0 L 4 cylinder MerCruiser with an Alpha One stern drive. I’ve owned this boat for almost 16 years and religiously maintained it. This year I replaced the spark plugs, rebuilt the carb (again!), and replaced the fuel filters. I say filters because I installed an additional fuel/water separating filter. She starts fine and purrs like a kitten, so I don’t believe I have anything wrong with the performance of it.

What I do think is I’m trying to do is to get a 4 cylinder to perform like a 6 cylinder. Let me start by saying I know this is unreasonable. But I think there are a couple of things I can do to tweak this boat. I now use the boat differently than I used to. I now have 4 adults and 3 shorties on it, and the shorties absolutely love my 3 person tube. If I had 2 adults on board, she planes off no problem. With 4 she really struggles. I have to catch the conditions just right or she won’t plane off. The wind, the direction, calmer waters… all of that has to be just right in order to plane off.

I really don’t want to buy another boat for the one week a year I go through this. Have you guys seen boat prices lately??? I love my boat and know it like the back of my hand at this point.

Besides lightening the load as much as possible, does anyone have any ideas on just a little more power forward to plane off? She’s real close.

Some of my thoughts:

1. Invest in a stainless steel propeller. I’m thinking it has less flex than aluminum, and might be just the “push” she needs to plane off.

2. Get an adjustable pitch propeller. I had one in the past and experimented with it. After a day of changing the pitch to every setting, I found that the original pitch from the factory was perfect, so I got rid of it. But now is a different situation. I’m thinking a pitch with more torque and less speed would be prudent for this one week while towing. However, this will be a slight pain in the butt as I’ll have to adjust it for cruising. I have to remove the propeller to adjust the pitch, at least if that’s how you still do it.

Edit: I found a #3 on ideas. I found an article on 4 blade stainless steel props instead of 3 blade. The seem like a great idea just for the one week I’m doing this towing.

Does anyone here have any ideas/thoughts/comments on my dilemma? Thanks in advance for your help.

Had a very similar size sea Ray with same engine

Try a lower pitch 4 blade. I used Michigan vortex 4 blades, 16” for skiing and 18” for genera cruising and tubing

As the kids got bigger ended up buying a 21 ft with a V8 …

 

[JPonLKN]

Sounds like your issue is getting on plane, and weigh distribution is huge on pulling and getting to plane. The boat will pull out of the hole and plane quicker when it is weighted a bit heavier at the front. Not enough to push the bow under the water or other wakes/waves, but enough to keep it from rising when the throttle is pushed. I have a Sundeck 210 with 5.0, and with 4 people in the cabin, it will not pull a skier, and struggles getting on plane. The Sundeck line is weight biased to the rear, more so than a typical bowrider. Plenty of power, but with weight in the wrong place, the power is useless for pulling and planning. Not fun telling the larger ladies to move out on the bow seats, but it works. You are the Capt'n, move the passengers around to get a good even to slightly forward weight distribution. I also found that a mild turn to the right (I think...been a while since I have pulled a big skier...could be left) would also help. Trim all the way down.

I also had a small scarab with a 4.3L V6 years ago, again, weight distribution heavy to the rear of the boat. Without the ability to push weight forward on the closed bow, I used a "whale tale" to help out. Slows the boat a bit, but it helped get on plane when pulling a skier, and also settled the chine walk around 60 mph to something manageable.