Not enough power?

[Cadeco]

Two weeks ago i went to the water w/ 7 people (total) and something did happen: My Islander has a F250 Yamaha ( of course 4 stroke) and With throttle down, around 5000/5200 RPMs I could not pass over 14/15 MPH., I called the mechanic and explain the issue, He told me that it should be a problem w/ the Hub on the propeller. I removed it and took to a propeller place to change the hub, today i got a call they told me that after putting pressure the HUB ( I guess this is how is called that rubber thing inside the propeller) It did not move and their opinion is that the hub is ok! What do you guys think about it? I don't think that 7 people would cause that problem, so, I will ask you guys for help. Has anyone had the same problem?
Thanks for all the incoming responses.

 

[white diamond]

Two weeks ago i went to the water w/ 7 people (total) and something did happen: My Islander has a F250 Yamaha ( of course 4 stroke) and With throttle down, around 5000/5200 RPMs I could not pass over 14/15 MPH., I called the mechanic and explain the issue, He told me that it should be a problem w/ the Hub on the propeller. I removed it and took to a propeller place to change the hub, today i got a call they told me that after putting pressure the HUB ( I guess this is how is called that rubber thing inside the propeller) It did not move and their opinion is that the hub is ok! What do you guys think about it? I don't think that 7 people would cause that problem, so, I will ask you guys for help. Has anyone had the same problem?
Thanks for all the incoming responses.

You are way under powered, especially for 7 people. That boat is rated for at least 400 horse power.

 

[glacierbaze]

Why are you duplicating the exact same post that you made on Friday, which already has 20 responses?

 

[family affair]

I read the other post. I can tell you with 100% certainty that 50% of the problem is your prop and 50% of the problem is your engine. Change one or the other and your problem goes away.
The smart option is to buy a spare prop of the same type and size but 2-3 pitches lower and only use it when you have 7 people on board.

When I had twin f150's the boat was a lot slower to plane with 7 people and full tank. That was with a total of 5.4 liters of engine displacement which = way more midrange power than a 3.3 liters of f250.

The part I'll guess about is the alarm. My guess is all the fuel you were forcing into the overloaded, over propped engine pushed you to an overheat condition. But it's just a guess.

 

[Ekea]

even with 7 people on a possibly underpowered boat, he should still be doing more than 15 mph with the engine running 5200 rpm. i dont think power is the issue. if power was the issue, he wouldnt be able to hit those rpm. assuming the boat is propped correctly, it does sound like a spun hub to me

 

[family affair]

Yes, he is at 5200 rpm, but the prop isn't biting. With my previous set up I could be at 28 mph at 4k rpm or 28 mph at 4700 rpm depending on how the engine was trimmed. The overload condition and possibly other factors are causing slip, ventilation, cavitation, traction loss, or whatever you want to call it.

 

[brdawg2001]

7 people these days is like 11 people 25 years ago....underpowered as well..

 

[Ekea]

7 people these days is like 11 people 25 years ago....

well, i will not argue that, haha.

still, turning over 5k, he should be doing better than 15mph.

 

[Cadeco]

Why are you duplicating the exact same post that you made on Friday, which already has 20 responses?

I received responses on my e-mail and tried to reply. Somehow a new post was opened.

 

[Halfhitch]

Don't sweat the double post Cadeco, one or the other will fade away.

When you say, you can only reach 15 mph but the engine is turning 5200rpm, is the bow pointed very high or has it climbed out of the hole and broken over into a planing attitude?

Just to give you some comparison numbers, my boat weighs a little under 5000lbs, so that gives me a little over 20 pounds of boat weight per HP. With less than 1/2 tank fuel, 2 people and moderated gear, calm saltwater I see 36 knots at 5900 rpm. Hardtop and no curtains.

 

[deepdesire]

I have an Islander. I would like to know where you can put seven people?

 

[Beyond A Wake]

If the motor revs that high the prop should push you faster. If the motor revs that high doesn't mean the prop is turning. You said they verified that the hub was not slipping. Something is fishy. Can you Detect cavitation? Meaning prop is not gripping as the water is "boiling" around it.

I have had underpowered boats, ex a 33ft Wellcraft that had difficulties planing with 10 people onboard, but the engines(inboards) were not revving high.
Pushing the load forward and "wiggling" the boat it came up and stayed there. THe deep V was one reason.

Good luck finding a less $$ solution

H

 

[Cadeco]

I have an Islander. I would like to know where you can put seven people?

I do not understand the question. For the size of the slander I guess it can handle seven people. I friend of mine can handle the same on a 23 Seafox, so, why not my boat?

 

[Ekea]

I have an Islander. I would like to know where you can put seven people?

helm chair, mate chair makes 2. you can put 2 more on the transom seat, thats 4. then 3 people on bean bag chairs or deck chairs and you have 7 with nobody up front or in the cabin. and that doesnt even use the backwards facing "jump seats"

 

[efx]

What year islander?

 

[Mustang65fbk]

I have an Islander. I would like to know where you can put seven people?

I've got a 228 Seafarer and have seating for 6 people, as well as have had over 10 people out on it at one time. Didn't feel at all unsafe or dangerous to me, but there are the two seats at the helm, the two rearward facing "jump" seats behind those, and then the two seats at the stern to the sides of the livewell. You could easily have 2-3 more sitting up on the bow cushions, another sitting on the livewell itself and so forth. No reason why one "couldn't" have 7 people on the boat at one point, though whether they "should" is a different story, especially depending on conditions.

 

[Mustang65fbk]

What year islander?

In a different post the OP mentioned he's got a 1998 model year, of which per the archived brochures, the last year for the 268 was 2001 and then it was changed over to the 270 in 2002. The maximum horsepower rating for a 1998 GW 268 Islander is 400 hp, but if the OP is only at just over half of that with a single F250 and also has 7 people onboard the boat, then I think that could definitely be a contributing factor to the equation. To the OP, I'd suggest going out by yourself and see what difference there is between just you being on the boat and having 7 people total onboard. If she runs and drives fine with just you out there, then I think you'll have found your problem.

 

[Cadeco]

What year islander?

1998

 

[Cadeco]

In a different post the OP mentioned he's got a 1998 model year, of which per the archived brochures, the last year for the 268 was 2001 and then it was changed over to the 270 in 2002. The maximum horsepower rating for a 1998 GW 268 Islander is 400 hp, but if the OP is only at just over half of that with a single F250 and also has 7 people onboard the boat, then I think that could definitely be a contributing factor to the equation. To the OP, I'd suggest going out by yourself and see what difference there is between just you being on the boat and having 7 people total onboard. If she runs and drives fine with just you out there, then I think you'll have found your problem.

You're correct 7 people is not absurd, but as you said" The specs are 400 hp. I was thinking of getting another 250 and be done, but the insurance would not like it! So, I'm in the process of looking for a pair of used 150's/175's or 200's (looking at 2 strokes for less maintenance and weight reduction)_

 

[Mustang65fbk]

You're correct 7 people is not absurd, but as you said" The specs are 400 hp. I was thinking of getting another 250 and be done, but the insurance would not like it! So, I'm in the process of looking for a pair of used 150's/175's or 200's (looking at 2 strokes for less maintenance and weight reduction)_

So have you been back out on the boat with only yourself? Also, I wouldn't necessarily turn a blind eye to a single 350 like a Suzuki or a Mercury, especially if you're considering brand new. A single Suzuki 350 is approximately 727 lbs, compared to twin 150 Mercury's which will be your lightest twin setup at 455 lbs a piece, or over 900 lbs total. I'd save the 175+ lbs as well as likely save a bit of money going with a single motor as opposed to twins, and go with a single Suzuki 350. Just my opinion, of course. A single Mercury 350 outboard is even a few pounds lighter than the Suzuki at around 695 lbs.