Sea Ray 280 and acceleration problem

[oysteinhermansen]

Hello. I live in Europe (Norway) and have a Sea Ray 315 (280 in the US) with a Volvo KAD 300 diesel engine. And I think the engine might starting to get breathing problems.

The boat has standard equipment (no generator) but with the following extra:
- 2 extra 110A batteries installed in the engine room
- windlass, anchor and 50 meter (150 feet) of chain

The boat uses about 40 seconds from 0 to 20 knots. It planes at 18 knots at this takes about 35 seconds. I have to move the trimtabs all down and trim the sterndrive all down to get enough lift.

Does a Sea Ray 280 with a gasoline engine behave in the same way ? Can anybody with a Sea Ray 280 with a Mercruiser 350 MAG MPI (which I guess is kind of comparable with the Volvo KAD300) tell me if their boat behave the same way ?

Has anybody installed bigger trimtabs then the ones that comes with the boat. I think they are 24x12, but Bennett also delives 30x12 for better lift.

I did the test with approx 85% (320 liter) of fuel and 60% (60 liter) of water). There were 2 people in the boat.

The Volvo KAD 300 has 285 hk and weight of 550 kg with the sterndrive.

Hope someone can give me some input and numbers before I do any more repair work.

Thank.

 

[Dave S]

You don't have any growth on the bottom of the hull or outdrive do you? If you do, I would try cleaning it off because the drag caused by bottom growth can cause a lot of problems. Has top end also dropped off on your boat?

I don't know whether there is an adjustment on a Volvo Outdrive to tuck the outdrive down a bit further. There is such an adjustment on the Mercruiser Bravo 3 and it helped me out immensely when I had a planing problem. You can look at this thread for more information on that. http://www.clubsearay.com/forums/viewtopic.php?t=3512&start=0

 

[Lady Renee]

I'm fairly new to the 280 group, yet I beleive that your diesel power is not so common here in the USA. We operate the Lady Renee (with Twin 4.3L V6 gasoline engine and Alpha 1 drives) in San Diego Bay.

With the same loading you describe, L.R. reaches plane speed, with zero trim tab and zero drive trim, in about 15 seconds/16mph. It takes another 8 to 10 seconds to get to 30 mph. I rarely retain WOT, generally I pull back the power at about 21 mph while continuing to accelerate. I continue to retard power hoding about 3750 rpm to reach and maintain 28/30 mph.

I realize these figure do not apply in your case. As I said I'm a novice, however I am of the opinion that trim tabs (on the 280 with OEM gas engines and their various power/weight ratios) are not very useful in attaining plane speed. From information I gathered, trim tabs are most useful for adjusting craft attitude (port/starboard - bow up/down) after reaching plane.

I find that 2 to 5 degrees of drive trim is very useful for maintaining crusie speed at lower RPM/fuel consumption.

I do find the 280 to be sensitive to fore and aft weight distribution.

I recommend trying zero trim on the tabs and full down on the drive while moving people to different fore/aft positions.

My two cents worth.

Ed

 

[Lady Renee]

280 Acceleration

I'm fairly new to the 280 group, yet I beleive that your diesel power is not so common here in the USA. We operate the Lady Renee (with Twin 4.3L V6 gasoline engine and Alpha 1 drives) in San Diego Bay.

With the same loading you describe, L.R. reaches plane speed, with zero trim tab and zero drive trim, in about 15 seconds/16mph. It takes another 8 to 10 seconds to get to 30 mph. I rarely retain WOT, generally I pull back the power at about 21 mph while continuing to accelerate. I continue to retard power hoding about 3750 rpm to reach and maintain 28/30 mph.

I realize these figure do not apply in your case. As I said I'm a novice, however I am of the opinion that trim tabs (on the 280 with OEM gas engines and their various power/weight ratios) are not very useful in attaining plane speed. From information I gathered, trim tabs are most useful for adjusting craft attitude (port/starboard - bow up/down) after reaching plane.

I find that 2 to 5 degrees of drive trim is very useful for maintaining crusie speed at lower RPM/fuel consumption.

I do find the 280 to be sensitive to fore and aft weight distribution.

I recommend trying zero trim on the tabs and full down on the drive while moving people to different fore/aft positions.

My two cents worth.

Ed

 

[Lady Renee]

280 Acceleration

I'm fairly new to the 280 group, yet I beleive that your diesel power is not so common here in the USA. We operate the Lady Renee (with Twin 4.3L V6 gasoline engine and Alpha 1 drives) in San Diego Bay.

With the same loading you describe, L.R. reaches plane speed, with zero trim tab and zero drive trim, in about 15 seconds/16mph. It takes another 8 to 10 seconds to get to 30 mph. I rarely retain WOT, generally I pull back the power at about 21 mph while continuing to accelerate. I continue to retard power hoding about 3750 rpm to reach and maintain 28/30 mph.

I realize these figure do not apply in your case. As I said I'm a novice, however I am of the opinion that trim tabs (on the 280 with OEM gas engines and their various power/weight ratios) are not very useful in attaining plane speed. From information I gathered, trim tabs are most useful for adjusting craft attitude (port/starboard - bow up/down) after reaching plane.

I find that 2 to 5 degrees of drive trim is very useful for maintaining crusie speed at lower RPM/fuel consumption.

I do find the 280 to be sensitive to fore and aft weight distribution.

I recommend trying zero trim on the tabs and full down on the drive while moving people to different fore/aft positions.

My two cents worth.

Ed

 

[goblue]

150 feet of chain?!!!! How much does that weigh?

 

[oysteinhermansen]

Thanks for all feedback. I will try the "have trim tabs to zero and use only drive trim" advice. I think that is the only one I have not tried.

I have also found out that the Sea Ray 280 is sensitive to weight back/front when it comes to loading the boat. I always ask people to move forward before I plane.

When it comes to "150 feet of chain" which equals 50 meter in Europe, it is very common in Norway and Sweden to use chain. The chain is a 6,5 mm chain and its used to anchor the boat with the bow towards all the small islands that we have. We can not use the anchor in the frond. The drive/propeller would hit botton long before we could go to dry land. A 6,5 mm chain weights abount 1 kg (2,1 lbs) per meter (3 feet). So 150 feet would have a weight of approx 50-60 kg. And then you can add a 15 kg (33 lbs) anchor and windlass.

I have checked with the local distributour in Norway and the say that a lot of people change the propeller after a year or so. They change to a propeller (duoprop) with smaller pitch. This descreases the top speed with 2 knots (29 instead of 31), but it also makes the boat accelerate alot faster. So I am going to try this as well. The sad thing is that Volvo duoprop is still under copyright and costs $2000 (no 3. party models).

Does anybody knows if bigger trim tabs will made the boat "not so sensible to loading" ?

 

[Dave S]

The sad thing is that Volvo duoprop is still under copyright and costs $2000 (no 3. party models).

Instead of buying new props you might try talking to a prop shop about changing the pitch on your exisitng props. I am sure that would be considerably less expense.

 

[smanier]

I have a hard time believing with two persons on boards that it is a trim problem. Is the problem new?

I am on plane with 3500 RPM in under 10 seconds, no trim, and usually my whole family on board (wife and five kids). I also get a top speed of just over 40 MPH.

 

[Presentation]

.....I.. have a Sea Ray 315 (280 in the US) with a Volvo KAD 300 diesel engine.....Mercruiser 350 MAG MPI .

Sorry for the editing…..but I am trying to get to the heart of this.

Are you saying you have a 280 sundancer with one engine and it’s a 5.7 liter?

This small of a engine was never offered in the USA. For a short time they offered a high RPM small block V8, known as a 6.2L but it was very underpowered so they don’t even offer it anymore.

I think the smallest engine in the 280 Sundancer is the 496 cubic inch / 8.1 liter big block V8.


Did this boat ever get on plane at a lesser time or did you just buy it?

 

[Presentation]

I have a hard time believing with two persons on boards that it is a trim problem. Is the problem new?

I am on plane with 3500 RPM in under 10 seconds, no trim, and usually my whole family on board (wife and five kids). I also get a top speed of just over 40 MPH.

This is what I would expect.

I am surprised at the 15-20 seconds with twin 4.3L Alpha's comment.

 

[beachcombersc]

I am surprised at the 15-20 seconds with twin 4.3L Alpha's comment.[/quote]

If your thinking this is long, I can smash this time!!! With 3/4 fuel, full water, and 5 aboard, I can amost run the thing out of the water...

Tab down just a tad, drives tucked full, and punch it!!!

280 w/4.3 alpha's with no bottom paint...

 

[oysteinhermansen]

Sorry for the editing…..but I am trying to get to the heart of this.

Are you saying you have a 280 sundancer with one engine and it’s a 5.7 liter?

This small of a engine was never offered in the USA. For a short time they offered a high RPM small block V8, known as a 6.2L but it was very underpowered so they don’t even offer it anymore.

I think the smallest engine in the 280 Sundancer is the 496 cubic inch / 8.1 liter big block V8.


Did this boat ever get on plane at a lesser time or did you just buy it?

The engine in my boat is a Volvo KAD300 diesel with a Volvo duoprop sterndrive. The engine has 285 HK and a torque of 570 nm at 3400 rpm. The weight of the engine and drive combinded is 550 kg. The engine has a volum of 3,6 L and has a supercharger and turbo.

I asked if someone with a Mercruiser MAG 350MPI (or any other single-engine installation) had numbers compared to mine.

 

[oysteinhermansen]

I thought I will just give an update (for other users who search this forum).

I have replaced my propellerset from Volvo C4 stainless to Volvo C3 stainless. This improved my accelleration dramaticly. I now only use half the time from 0 to 20 knots compared with my C4 propellers.

Here are some numbers for you.

RPM.............Speed in knot with C4......Speed in knot with C3
3000..............20,9.............................18
3500..............26,0.............................23,5
3750..............29,5
4000................................................28,6


Accelleration from 0 to 20 knots
With C4: From 30 to 35 seconds
With C3: From 15 to 20 seconds

As you can see the engine need more rpm's to get the same speed. But top speed is only 1 knot lower (but RPM is higher). I do not know how this will affect the usage of fuel since the rpm is higher but the engine has "an easier job".

Since I prefer accelleration compared to top speed, and think that I will stay with my C3 propellers.

 

[fc3]

I'd say your boat was excessively stern-heavy and possibly over-proppted. What is an 110A battery? I could not find them with Google. How much do they weigh? Sounds like with your stern mounted anchor and chain you have about 75 extra Kg aft. If the batteries are also very heavy, that would reinforce that the boat is stern-heavy. Asking people to move forward also confirms the boat is stern heavy. I would recommend moving weight forward or reducing weight aft before changing props. Not only do you lose top speed with the C3s instead of the C4s, but you may also lose some economy.

Best regards,
Frank

 

[oysteinhermansen]

I'd say your boat was excessively stern-heavy and possibly over-proppted. What is an 110A battery? I could not find them with Google. How much do they weigh? Sounds like with your stern mounted anchor and chain you have about 75 extra Kg aft. If the batteries are also very heavy, that would reinforce that the boat is stern-heavy. Asking people to move forward also confirms the boat is stern heavy. I would recommend moving weight forward or reducing weight aft before changing props. Not only do you lose top speed with the C3s instead of the C4s, but you may also lose some economy.

Best regards,
Frank

The 2 ekstra batteries (2x100Ah) and the stern mounted anchor (with 50m chain) has a combinded weight of about 150 kg (approx 330 US pounds). So I do agree that the boat is stern heavy. But do you (or any other) have any suggestion about where I can install the batteries ? But since this boat also is delivered with a generator as an option (I do not have it) I assume that the boat must be designed to support this weight. A boat with double engine installation has more weight in the stern then mine (single installatition).

 

[Dave S]

The 2 ekstra batteries (2x100Ah) and the stern mounted anchor (with 50m chain) has a combinded weight of about 150 kg (approx 330 US pounds). So I do agree that the boat is stern heavy. But do you (or any other) have any suggestion about where I can install the batteries ? But since this boat also is delivered with a generator as an option (I do not have it) I assume that the boat must be designed to support this weight. A boat with double engine installation has more weight in the stern then mine (single installatition).

The 280DA is an interesting boat when it comes to the weight in the aft section. Because of the various engine and outdrive combinations available, the weight varies greatly. You should look at this thread where we had a discussion on the matter and where some weights are given based on the combinations of engines and outdrives. http://www.clubsearay.com/forum/showthread.php?t=2928

The only thing not covered in that post is the deisel option but if you can find the weight of your outdrive and engine, then you can compare it to the other weights of the various gas powered combinations shown here.

 

[Nehalennia]

After looking at some of the data on Mercruiser's website, I would think that for the
280DA the 4.3L twins are the most efficient package. The power to weight ratio is better and the fuel burn should be better at a common cruising speed. The best part of the 4.3's is the torque is very good for size. I would think though that with your deisel configuration the C4's seem to show better numbers all the way around, but for the weight of your engine/outdrive configuration + the extra batteries and chain/anhor, drops that power to weight ratio very low prompting the C3's just to get out of the water. Then once on plane you're just burning more fuel.
Best of luck.

 

[oysteinhermansen]

After looking at some of the data on Mercruiser's website, I would think that for the
280DA the 4.3L twins are the most efficient package. The power to weight ratio is better and the fuel burn should be better at a common cruising speed. The best part of the 4.3's is the torque is very good for size. I would think though that with your deisel configuration the C4's seem to show better numbers all the way around, but for the weight of your engine/outdrive configuration + the extra batteries and chain/anhor, drops that power to weight ratio very low prompting the C3's just to get out of the water. Then once on plane you're just burning more fuel.
Best of luck.

The engine (inkl duoprop sterndrive) has a combinded weight of 580 kg (1280 lb). This is approx the same as the Mercruiser 6.2L MPI with Bravo-III drive. Does anybody on this forum have this combination ? Can you give me some numbers (times) from 0 to 20 knots (23 mph) and maybe time to plane ? (The KAD300 has 285 hk and 570 nm/420 lb-ft torque at 3400 rpm).

It is correct that the C4 might be a better alround propeller for my boat. But using 35 seconds from 0 to 20 knots, and about 30 seconds to plane, is not a option. With C4 propeller my boat did 31 knots at max. With the C3 is does 29 knots. I know that the engine will run at approx 200 more rpm to get the same speed, and therefor use more fuel. But then again the engine will need less power to drive the propeller (less resistance) so I think that I will not see the "full picture" until after next season.

And if it turns out to be a problem I can install the C4 once again and use the C3 as backup.

 

[Nehalennia]

The 6.2 with BIII is 1019. The 6.2 has 320 hp but the torque will be good. That's 260+ lbs more you'll have. I don't own a 280DA but have done a little research before buying a 260DA(sale pending) on the 28DA. I just found that a 280DA should have twins. I think Doug's dream 6.2's would be ideal for that boat but fuel burn may be cost prohibitive so the 4.3's seemed to me to be the next best setup.
Hopefully you'll find your new setup to benefit you as you hope. Best of luck