1999-01 280 SS

dano ss

New Member
Jul 11, 2018
1
Boat Info
1999 Sea Ray 280 SS
Engines
Twin 350 mags
Own a 99 280SS with twin 350 mags. Only 120 hours, runs beautifully and fast - 60 mph. Sweet spot is about 3500 rpm @ 38 mph. Below that, she gets sluggish and wants to drop off plane. Is it possible to cruise at 30 mph? Because of the twins she's stern heavy. The bow rides a little high and will porpoise without constant trim adjustment. Has anyone had luck putting weight in the bow to even the ride? Is it possible to go slow in this boat? I know - tough problem to have.
 
Put an all chain rode in the anchor locker... it's like having a 180 pound passenger up there.
 
I rarely if ever use my tabs so I never think of them when trying to stay up on plane around 30 but you make a very good point. Trim in and tabs down should give the stern the lift it needs. Going to try next time out but I love cruising at 3500/38mph.
 
Absolutely - use those tabs - that's what they're there for. You may find that you can get more benefit by using more tab and less drive trim. Tabs won't scrub your speed quite so fast. Meaning, try putting your drives in a relatively neutral position - parallel with the hull (might be about 1/4 on the gauge), then use your tabs to fine tune. You should be able to run quite a bit slower yet still stay on plane. If you need to, put the drives negative, but try without getting too aggressive with drive trim.

Since it sounds like you're not too familiar with the use of tabs, it may take a little getting used to. But be patient - once you're comfortable with them you'll really like it. Try this, too - put the tabs and drives all the way down and watch how nicely the boat comes out of the hole.
 
Speeds under 25 are a challenge with a twin 280. Even with full tabs she'll squat and throw a huge wake. I can almost guarantee that you can make 25 and up work though. We have manitee zones/seasons with a 25 MPH speed limit. Faster is more comfortable, but I can maintain "legal enough" speeds and have never had to ask a passenger to move to the bow.
 
Dano has the 350 MAG's, so he likely has the Bravo drive. That "should" help him a little more, as well - being a Bravo prop and more HP.
 
300 HP compared to my 250 (I think), but torque would be about the same, no? I wouldn't think the ponies would do much at the lower speeds.

He also listed a Bravo 1 - that's a regular single prop. A better drive for sure, but again, I doubt much help at 25 mph?
 
He (Dano) didn't/doesn't mention if he has Bravo I's, but I believe that was the standard when the 350MAG was optioned. Alpha's are still used with 350MAG's, but in this case I think it was a "package" deal. Dano can clear that up.

I believe the Bravo prop provides a little more grunt/power/whatever you want to call it compared to an Alpha. I know it is quite a bit heavier/robust than the Alpha, but I think the prop also adds some performance gains (but only attainable with more power, to begin with). How much, I do not know.

Torque, in a marine engine, is one of those things I've been hard pressed to find numbers on. Strange, too, since torque is a "real" number and HP is a calculated number based on torque and RPM. I'm not positive, but I think the 350 "MAG" engine may use a different cam and have better torque, along with HP. The extra torque (and possible WHERE the HP comes in at... HP "curve") could provide the power for the bigger prop.

I'm skirting around the edge of my knowledge base here on props, but it seems to make sense. Or... I could be way off base! The only thing I can tell you, with certainty, is that (from running the same models of boats with different engines/drives over the years) is that there is a notable difference in what a 350 MAG provides over the 350 carb'd... or even the 350EFI (260HP). It's not something you would go and spend money on switching engines for - but it is noticeable.
 
He (Dano) didn't/doesn't mention if he has Bravo I's, but I believe that was the standard when the 350MAG was optioned.

I was looking at SteveRuss's info.

I'm not sure either. I would be surprised if a cam produces noticeably more torque, but that's just a gut feeling.
 
Own a 99 280SS with twin 350 mags. Only 120 hours, runs beautifully and fast - 60 mph. Sweet spot is about 3500 rpm @ 38 mph. Below that, she gets sluggish and wants to drop off plane. Is it possible to cruise at 30 mph? Because of the twins she's stern heavy. The bow rides a little high and will porpoise without constant trim adjustment. Has anyone had luck putting weight in the bow to even the ride? Is it possible to go slow in this boat? I know - tough problem to have.
I know this post is old but what props are you running just got a 01 28 ss
 
I know this post is old but what props are you running just got a 01 28 ss
Dano ss has not visited CSR since July 2018 when he first posted.

But best of luck and welcome to CSR!
 

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