Sailfish 272 with waterlogged foam?

DennisG01 said:
Compression is fine.

Dump the fuel filters into a clear jar (one for each filter). Let it sit for an hour and then inspect and post pics.

I assume your engine has some type of VST tank with a hi-pressure pump inside? Inspect the inside of the tank and, likely, some type of filter on the hi-pressure pump.

Pull the plugs and inspect.

Monitor fuel pressure while running.

For good measure... take a run with the fuel cap off.
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I can take a peak at the gas in the filters but I think the gas is getting through just fine since I was burning 40 GPH during the wide open throttle test.

Isn't the change is prop-slip percentage from 5% to 36% i smoking gun of sorts? If I think of a car analogy, prop slipping is like tires screeching rubber which is usually a sign of a healthy car engine. The prop-slip percentage change would seem to indicate a problem with the hull or the props and there is no visible damage to the SS props.
 
Duncan said:
I can take a peak at the gas in the filters but I think the gas is getting through just fine since I was burning 40 GPH during the wide open throttle test.
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As I mentioned earlier (I think), it may be about fuel QUALITY. Yes, a fuel water sep does exactly that... but not perfectly. Plus, using an ethanol additive can break down the water molecules small enough where they pass through. Generally, that's a good thing as it gets rid of minute amounts of water safely - but if there's a enough of it, it could cause running issues.

The point is, some investigation needs to be done - from what you have been writing, signs point towards fuel issues.
 
A bit of a pain with twins, but get a couple of external 6 gallon fuel tanks, and connect them as directly to the engines as possible (avoiding fuel lines and filters upstream of the motors). Run the boat on the portable tanks. This will at least eliminate a clogged inline filter, fuel line, tank pick up, or tank vent issue. Since you are seeing both engines with same issue, I'd be looking upstream for some sort of blockage. Running on a set of portable tanks will narrow down where the issue occurs.
 
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bad fuel would not make his prop slip go up 7x. it would reduce his ability to produce power.

your scupper drains look to be about right for that boat, many in that vintage sit lower.

it looks like i can see growth on the bottom of the hull in the pic (looks like barnacles). it could be an illusion, but to me, more and more signs are pointing to a dirty bottom
 
Ekea said:
it looks like i can see growth on the bottom of the hull in the pic (looks like barnacles). it could be an illusion, but to me, more and more signs are pointing to a dirty bottom
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I looked at the picture again this morning and noticed the barnacles on second look too, barnacles all over would definitely slow it down and impact the performance
 
Ekea said:
bad fuel would not make his prop slip go up 7x. it would reduce his ability to produce power.

your scupper drains look to be about right for that boat, many in that vintage sit lower.

it looks like i can see growth on the bottom of the hull in the pic (looks like barnacles). it could be an illusion, but to me, more and more signs are pointing to a dirty bottom
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We don't know that he has prop slip. He assumed he did - but multiple factors can cause a drop in RPM... one of them would be fuel quality.

If those are barnacles... yup, different story.
 
DennisG01 said:
We don't know that he has prop slip. He assumed he did - but multiple factors can cause a drop in RPM... one of them would be fuel quality.

If those are barnacles... yup, different story.
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but if he is only getting 28 mph at 5k, then its either prop slip or spun hub. a spun hub would likely allow the engine to reach full rpm though
 
Ekea said:
but if he is only getting 28 mph at 5k, then its either prop slip or spun hub. a spun hub would likely allow the engine to reach full rpm though
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Yeah, a spun hub would likely even result in over revving.

Now, admittedly, I haven't found a need to mess with prop slip calc's over the years, so please redirect me if I'm not thinking of this correctly... I "thought" prop slip calc's were really only helpful when switching props and trying a different design? In this case, prop change hasn't been done since he's still using the same ones?
 
I've been reading with interest and the only thing that would make sense is that the prop hubs are slipping. Both of them is plausible after all they have been through the same time/process. It is hard to test yourself for incremental slip so take them to a prop shop and test them.
Good luck finding the reason as you've been through most of it.
Or you have some hidden big weight onboard so weighing it all is one way but make sure you have a reference to compare with.
H
 
seasick said:
When the boat tops out at 5000 revs, if you run like that for a while do the revs stay steady or do they change up and down?
Something is just not seeming right to me. When you top out at 5k is the hull on plane? If not om plane I could understand the slip percentage but if on plane I am at a loss. Just to cover the bases again, are you certain that the hull is clean? Did you look at it?
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The revs stay steady at 5000 RPM. When I saw the large slip percentage I thought maybe the propeller hubs could be slipping but the RPMs are too steady throughout the operating range for that. (I do have another set of props but the pitch is higher (19" vs 17".)

Its on a plane at WOT and going 28 mph. It feels a little sluggish getting up on a plane but gets up okay. It is feeling like a heavy underpowered boat.

When I launched it the bottom was clean. There could be some barnacles growing on it now as noted above but it was clean when it went in.

I have a few phone calls in to marinas with travel lifts. One place said their scale is accurate to 100 lbs and I asked them if they could just lift it up, weight it, and put it back down. They call that a short lift and want $15/ft for that ($405). They say they may be able to do it tomorrow so I will just do it to see I can confirm or rule out the extra weight theory. I have a moisture meter and maybe I could use it when the have they boat lifted out of the water, or just give the hull some raps where the potentially wet foam is.

Thanks
 
DennisG01 said:
Now, admittedly, I haven't found a need to mess with prop slip calc's over the years, so please redirect me if I'm not thinking of this correctly... I "thought" prop slip calc's were really only helpful when switching props and trying a different design? In this case, prop change hasn't been done since he's still using the same ones?
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Yes - I am using the same props but comparing the prop slip numbers from 8 years ago to what I am getting today. The props haven't changed but the behavior of the boat has. The WOT RPM dropped from 5800 to 5000 and the top speed dropped from 48 MPH to 28 MPH. Hopefully I'll get the boat weighed tomorrow and that will shed a little light. Prior to weighting the boat, I will remove all the gear, tools, water, etc. and then repeat the WOT test one more time.
 
Duncan said:
When I launched it the bottom was clean. There could be some barnacles growing on it now as noted above but it was clean when it went in.

I have a few phone calls in to marinas with travel lifts. One place said their scale is accurate to 100 lbs and I asked them if they could just lift it up, weight it, and put it back down. They call that a short lift and want $15/ft for that ($405). They say they may be able to do it tomorrow so I will just do it to see I can confirm or rule out the extra weight theory. I have a moisture meter and maybe I could use it when the have they boat lifted out of the water, or just give the hull some raps where the potentially wet foam is.

Thanks
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im glad that you will be there, as i am sure you will be able to inspect the bottom for growth. it doesnt take much at all to slow the boat down. try to get some pics for us if you can.

as far as weight, the difference between a full tank and empty is over 1000 lbs and that wont change your WOT speed much more than a couple mph. think of how much weight you would need to loose 20 mph.
 
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With it being both engines - for it to be prop slip, would not the same change have to have happened to both props?

It is most certainly not weight, as several of us have pointed out. If there was so much extra weight to impact performace to this extent, the scuppers would be below water.

Unless there is a ton of growth on the bottom, this still feels like a fuel issue. It happens to both engines. Has to be something far more likely than both props going bad after storage.

Fuel restriction issues will sometimes cause a motor to put out limited power.
 
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Seems unlikely that you have spun both prop hubs exactly the same but easy while it is out of the water to replace those.

Even a little bit of hull junk can cause a huge loss of efficiency. Easy to have it cleaned while it’s out of the water. Might as well get your value with it hauled out. This could be the primary cause of prop slip.

I don’t know much about the ETEC motors but direct injection systems are very particular and further complicated by the system that mixes the 2 cycle oil. The DI fuel pumps run at really high pressure and are very sensitive. Just sitting for 2.5 years you can get corrosion and deposit build up. But since both motors seem to run the same probably not the primary cause of low rpm. Same for spark, the etec probably has multiple coil packs and a lot of engine management that might limit power if things are not exactly right but probably would not impact both motors at the same time.

More likely that when you drained the tanks (how did you do this) there was still fuel in the bottom that has varnished around a strainer or screen somewhere in the line. And empty tanks can still get corrosion. When you fill them up, a bit of that gets into the system and the screens/strainers and filters get jammed. Forget if you changed the filters again. Maybe a prior owner added a filter somewhere in the line. I’d think that both engines might be fuel limited as previously mentioned in another post.

Waterlogged? I guess you will find out when you weigh in, do you have a reason to believe the wrap was compromised? Fresh water in the bilge? I guess a slow leak somewhere could add up but would think that would be in an isolated area.

Good luck. Sometimes it’s not just one thing but you’ve already been thinking about that.
 
Seems unlikely that you have spun both prop hubs exactly the same but easy while it is out of the water to replace those.

Even a little bit of hull junk can cause a huge loss of efficiency. Easy to have it cleaned while it’s out of the water. Might as well get your value with it hauled out. This could be the primary cause of prop slip.

I don’t know much about the ETEC motors but direct injection systems are very particular and further complicated by the system that mixes the 2 cycle oil. Just sitting for 2.5 years you can get corrosion and deposit build up. But since both motors seem to run the same probably not the primary cause of low rpm.

More likely that when you drained the tanks (how did you do this) there was still fuel in the bottom that has varnished around a strainer or screen somewhere in the line. And empty tanks can still get corrosion. When you fill them up, a bit of that gets into the system and the screens/strainers and filters get jammed. Forget if you changed the filters again. Maybe a prior owner added a filter somewhere in the line. I’d think that both engines might be fuel limited.

Waterlogged, I guess you will find out when you weigh in, do you have a reason to believe the wrap was compromised? Fresh water in the bilge? I guess a slow leak somewhere could add up but would think that would be an isolated area.

Good luck. Sometimes it’s not just one thing but you’ve already been thinking about that.
 
DennisG01 said:
Can I ask... why have you convinced yourself there's a weight problem when there is no evidence to support that?
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Good question and a good time to summarize. I've convinced myself that the problem is the hull and not the motors. The primary reason is because the prop slippage had increased greatly from 5% to 35% during WOT testing and the WOT RPM dropped from 5800 to 5000. I did testing when I first put those props on and previously at 5000 RPM I was running about 41 MPH. Now it's only going 28 MPH at 5000 RPM so unless the props are slipping smoothly and the exact same amount on each motor (which seems unlikely) something about the hull has changed. The engines with the current fuel are turning the props at 5000 RPM but the boat is going (41-28 = 13 MPH) slower then years ago for the same RPM. That rules out the motors and fuel - the motors are doing their job, right? They are turning the props at 5000 RPM but the boat isn't moving like it should.

I noticed the change after launching in 2022 after having sat out the 2020 and 2021 seasons due to covid and other issues. The thing I noticed first was the drop in gas mileage from ~1.4 MPG down to 0.9 MPG.

I agree there could be something about the bottom contributing to this but nothing has changed with the way I use the boat. I have it hauled in the fall and pressure wash a layer of scum off the bottom and scrape off a few dozen barnacles. There is never any serious marine growth like green stuff hanging off it. In the spring I touch up the Hydrocoat bottom paint, wax the hull and launch.

The boat was shrink wrapped during the three winter layup. (I was surprised how filthy the boat was when I uncovered it.)The guy who installed the shrink wrap cut two U-shaped slices in the wrap on either side of the bow pulpit for ventilation. I guess it's possible that small amounts of rain water could have gotten in there and found its way into down into the hull somehow. Maybe thought the anchor locker?

Hopefully the travel-lift guy can accommodate me today to get it weighed and inspect the hull.

I appreciate everyone's help and suggestions and patience :)

Thanks,
Duncan
 
It's your money. Obviously we can't convince you that it is not weight that is your issue.

Your assumption that the motors are doing their job is not accurate.

I'm no expert, but anytime I've been in a situation where troubleshooting is needed, rule of thumb is to start with the easiest and most likely, then work to the unlikely and obscure. There are zero signs it is weight. Scupper level, to noted performance differences on other boats between running light and fully loaded.

Pages have been written about fuel issues on boats, particularly with the advent of ethanol fuels, and the long off seasons for boats.
 
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