44 Sedan running slow

[Ray K]

I'm looking at a 44 Sedan with QSC500s. The WOT rpms get up to about 2650 but the speed is only a little over 31mph (26.9kn). At around 2100rpm it's only doing around a little over 21.5mph (18.6kn). I think from all the review info I've looked at plus having driven a friends 44 Sedan recently the speed should be much better. Around 35mph (30.4kn) WOT and 25mph (21.7kn)at 2100. The boat was recently hauled and is clean with fresh bottom paint. Could there be an issue with the props? I thought that if the pitch was off it wouldn't reach WOT rpms, but it does. Could the props be off in such a way to still allow them to spin up to WOT but the thrust not being where it should be due to a few blades being off on both? The sync was off and one engine got about 30rpms more at WOT so they were close. I didn't drive the boat so I can't comment on whether it was trimmed out properly.

 

[swaterhouse]

2650 is not enough, QSC500's should be able to easily spin 2665 and load should be well under 100% at that RPM especially if running light with a clean bottom as it will only get worse from there.

Props need to be reworked to increase RPM.

What was the condition of the bottom?

 

[Ray K]

The boat had just been hauled, surveyed, bottom cleaned and repainted. I agree I would like to see 2680 at WOT on both. It still doesn't explain why it's only going 31mph at 2650rpm and 21.5mph at 2100rpm. If these numbers were in knots it would be dead on I think, but not when in mph. I didn't mentioned it before but this boat does have a hydraulic lift, however it was unloaded as well as the boat is a dealer boat so it's not full of personal gear. I've been on a 44 Sedan and driven it. It runs the same if 1 or 2 people are on it or 6 so I can't see an empty lift accounting for the difference.

 

[Converse48]

As I recall, at 2680 you should see 29 knots on that boat. If the bottom was clean, it sounds like a prop issue. Under-propped maybe. Were you able to get to 100% load?

 

[Ray K]

It was burning 26gph (52 total) at WOT so that would almost be 100%. I did speak to another owner with a hydraulic lift and he said he lost close to a knot after adding the lift. This boat didn't have any gear on it, but the empty lift weighs about 600lbs. Maybe having the props checked and altered would gain a little. Since it can't quite reach 2680rpm though I would have to remove a bit of pitch which I'm afraid might lose more speed.
The odd part is that the one with the 480CE engines can hit 30 knots. Maybe this model is very sensitive to the weight of the swim platform. I wouldn't have thought this the engines and fuel tanks are midship. Express cruisers with V-drives and fuel tanks more aft seem to usually be more sensitive to adding weight at the stern. One thing I should mention if that's the case the boat with the 480CE had about 600lbs added by Sea Ray under the port bed in the guest stateroom to counter act the slight list to starboard this model has. Wonder if the weight further forward and to port is actually helping the balance of the boat.

 

[Ray K]

bottom was clean and just painted.

 

[tcourtney]

Ray how much fuel was in the boat how much water also and was tide and current going against you. I have same boat and I have all the numbers from my sea trial a year ago mine was 27.8 knots at 2660 starboard and 2640 port. I though it also was a little low too and bottom was clean and after I bought the boat I cleaned props and shafts and got 2680 both motors and 29 knots with all my kids and wife's stuff on the boat love the boat doesn't have a hydraulic lift tho but am thinking of putting one on what kind of lift is on boat your looking at.

 

[Ray K]

The boat had 1/2 fuel and not much gear as it's a dealer trade. I don't recall how much water. It was on an inland freshwater lake so no tide or current to deal with. I have a friend who can hit 30 knots with his with the 480CE motors (2006). His cruise is 21 knots at 2100. I've driven the boat so I know it's true. I've also go a bit of info from a few others now as a result of my query. It seems most can't hit 30 knots. 2 others have come in at 28.8 and 28.5 knots at between 2650 and 2700rpm. Another reported a slight drop in speed (about 1 mph) after adding a hydraulic lift. So maybe this boat I'm looking at could gain a little by tuning the props so get 2680rpm. My friend who gets 30 knots did have his props tuned a few years ago but he got the same after. He also had Sea Ray add the ballast fwd to correct the starboard list when new mentioned above. Maybe that helps. Maybe this boat is too empty. Most of the weight you would add for personal belongings is in the galley, staterooms etc. The water tank is more forward as well. This boat also has the 1/2 hardtop option. It's not that big so I can't see it adding much weight and the steeper angle of the front isenglass with this option can be creating that much wind resistance. I'm glad to get a bit of feedback for a few owners though so at least I have some first hand info to compare this boat to.

 

[480ces]

I don't think you'll see much if any gain from tuning the props. If anything you'll see a loss in speed if the engines load at a higher RPM.

You may may see a gain going to a better prop (CNC'd like Acme), budget ~12k.

I'm betting the difference is in the hardtop and general weight gain boats see model year to model year.

Other things to look at though...

Have you you played with the tabs at all? There may be a knot or so there.

Was loading or fuel burn the same on both engines?

Other areas to look at would be the shafts (alignment, cutless), rudders (alignment), even year to year underwater exhaust changes could cost a knot.

 

[Alex F]

I know the model very well. You've received few good points from others. I know there are number of variables involved here, but before I can comment on possible causes, I have to ask what props is she swinging (dia/pitch/cup)?

Also, what was the buddy and conditions of water you've tested in? Biggest reason I ask, b/c you could be in the calmest river, but going against 3-4kts current (and possibly against 15kts wind on top of it) will do the trick on screwing up your numbers.

My first reaction, QSC500 with fresh bottom, 1/2 fuel, no lift with a heavy tender on it, not much gear and people......26.9kts....yeah, that's on the low end.

As others said, as soon as you touch the pitch to gain extra RPMs, you will only loose more speed. Yes, ideally you want to see as close to 2700RPMs as possible. But, 2650 is not so bad as long as you see this number all season long you'll be fine.

Tabs - critical part of the test. You'll need about 1/2-2/3 down. Fully deployed will cost you couple knots when doing WOT test.

 

[Ray K]

tcourtney, Missed one of your questions. I've look at 2 with different hydraulic platforms. One has the Sealift single cylinder type with about a 3 foot long deck. The other one has a GHS dual cylinder one with about a 4ft deck.

 

[Ray K]

jmwarren, I wasn't driving the boat so I can't comment on the tabs. I know that makes a bit of adifference on most boats. It did on my last one but maybe a knot or so like you suggest. Fuel burn was 26gph on both at WOT. If I get that far with this one I'll definitely look at the underwater gear when out of the water.

 

[Ray K]

Alex F, According to the data I have they were the stock props 26 x 27. I can't comment for sure about cupping but a friend 44 has cupped props I know for sure. The run was in an inland lake. I was not present for this test. This was just the broker offering some initial info when the boat was traded in. I'm not that far along yet. If I pursue this boat further I'll have a close look at the bottom gear and I think due to the difference in the WOT RPM from port to starboard the props need to be looked anyways. If I am driving it I would also be checking tab position as well. On my last boat not enough or too much tab would loose speed.

 

[Alex F]

Alex F, According to the data I have they were the stock props 26 x 27. I can't comment for sure about cupping but a friend 44 has cupped props I know for sure. The run was in an inland lake. I was not present for this test. This was just the broker offering some initial info when the boat was traded in. I'm not that far along yet. If I pursue this boat further I'll have a close look at the bottom gear and I think due to the difference in the WOT RPM from port to starboard the props need to be looked anyways. If I am driving it I would also be checking tab position as well. On my last boat not enough or too much tab would loose speed.

I understand the situation now. That explains a lot. Broker's info is good, but I would never use it as my driving factor, especially outdated info. Unless you or a hired professional on your behalf is present during the test, while the boat has clean running gear and the bottom, we can speculate all day long. Based on the info you've provided, I don't see any reason why this boat can't get to 30kts at WOT. It's either some piece of info missing or something was off during the test.

 

[Ray K]

It was burning 26gph (50 total) at WOT so that would almost be 100%. I did speak to another owner with a hydraulic lift and he said he lost close to a knot after adding the lift. This boat didn't have any gear on it, but the empty lift weighs about 600lbs. Maybe having the props checked and altered would gain a little and even them out from port to starboard. Since it can't quite reach 2680rpm though I would have to remove a bit of pitch which I'm afraid might lose more speed as some of you have thought as well.
The odd part is that the one with the 480CE engines can hit 30 knots. Maybe this model is very sensitive to the weight of the swim platform. I wouldn't have thought the 44 Sedan with the engines and fuel tanks midship. Express cruisers with V-drives and fuel tanks more aft seem to usually be more sensitive to adding weight at the stern. One thing I should mention if that's the case the boat with the 480CE had about 600lbs added by Sea Ray under the port bed in the guest stateroom to counter act the slight list to starboard this model has. Wonder if the weight further forward and to port is actually helping the balance of the boat. That was a fix from Sea Ray as apparently they all list slightly to starboard especially if low on water.

 

[bmac]

I don't know about them all listing....mine did not. Also, fuel flow is not necessarily a good indication of engine load. I'd bet a prop tune up brings all the numbers in line.

 

[Ray K]

Alex F, The one other boat I'm comparing too was run in one of the Great Lakes so no current is an issue. This one had 26 x26 props and the 480CE engines. The boat I'm looking at has 26 x 27 props which I believe were standard with the QSC500 engines. The other 2 I compared to also had QSC500 engines. The odd part is that the one with slightly less HP is faster, however it does not have a hydraulic lift or hardtop. The boat I'm looking at was tested in a river but based on the info I have was actually going down river which doesn't help the slow situation. Currently we are going to try and see if we can negotiate an agreeable price on the boat and then I can go and run the boat myself. As you mentioned the tabs play an important roll in all of these boats. I have no idea how they were setup and cruise or WOT. I'm concerned that with the current cruise numbers it uses about 15% more fuel. I don't want to be chasing an issue like this after I buy it only to find out it's as good as it gets.