280 Sun Sport

T

toger13

New Member
Feb 21, 2015
5
uk
Boat Info
1998 280 SunSport
Engines
350 MAG Bravo 1
Hi guys

A bit of a random question here

I have a 1998 280 sun sport mine was a twin 350 mag model with bravo 1's I know this boat was offered standard with a single big block and twins was an option

Does anyone know how they balance the boat with the different engines putting more weight in the front on the twins or more weight in the rear or nothing at all?

The question comes comes about because I have swooped the engines for LS2 motors running 490hp each these engines are quite abit lighter been all aluminium so it's very nose heavy probably sits 4 inches higher than before judging from the antifoul line

It drives like a dream with 8-9 adults in and goes like a rocket ship but with just 2 people in it hits the wall at 50 mph gets there quick but struggles after that

So I was wondered if sea ray stuffed some weight in the nose some where lol

thanks
Si
 
Si, if it runs bow down ("nose heavy") that could be from swapping out the engines, but that is easily corrected by using the trim on the engines. The trim should be all the way down when you're coming from an idle or dead stop, then as the boat makes that transition from being in the water to riding on top of the water, that's when you want to trim up the lower units.

As you keep trimming them up you'll hear the engines start to run a bit smoother and your speed will increase without any increase in throttle. Then you will find a point (as you keep trimming up) where the boat starts to porpoise; that is the point where you've gone too high and it's time to trim it back down a bit.

Listen to the engines as you're trimming up. They'll tell you where the sweet spot is. BTW, that sweet spot varies with your passenger load, fuel load, etc. Just get used to listening to what your engines are telling you.
 
Hi

thanks for the reply

ye I have tried trimming out like you say but doesn't seem to have the levrage to un stick the bow

I different prop may help I'm running a rev 4 at the moment which I believe is a stern lifter? But could be wrong

Thanks
Si
 
I've never seen SeaRay compensate or balance for different engines. That doesn't mean they haven't, but the 400DA was available in gas and diesel and I can tell them apart from 100 yards by the way the stern sits.

I can't distinguish between a twin or single 280 from a distance though, which is interesting. Do you have an estimate of how much lighter your new engines are? I would also think that carrying full fuel would make a difference. As far as I know, your tank in the SS is in the same place as the BR - right up against the aft bulkhead. If I needed ballast, I'd be tempted to stuff a couple of extra batteries on the shelves alongside the engines...

I'm confused that you can't trim up. It sounds simplistic, but have you confirmed that your tabs and drive trim are as operational as you think they are?

Can we see some pictures of these beasts?
 
Boat porn - that's awesome. I could see the pictures, but couldn't play the video.

We can carry 800-900 lbs of fuel... Have you run her with the fuel topped off? I'm not sure water would make much difference, being at about amidship and a small tank. Does the SS carry more water than the BR's 24 gallons?

Group 31 batteries are about 70 lbs each. The good thing about those is you can put them far back and they're not just dead weight - the power could come in handy. Up that stereo amp a few sizes, or x10. Install a inverter and get a really big blender...
 
Hull design plays a very important part in how fast a boat can go. Even with more horsepower, the hull will only yield so much speed. The 280 is very wide and not so long so you are not going to get much beyond 60 - 65 no matter what the power is. Look at all of the go fasts, they are missile shaped for a reason. I can't understand you hitting a wall at 50. My sea trial with 5.7 efi B1s, 1/2 tank of gas, 2 people and no bottom paint we hit 56 on GPS. after paint, I've topped out at 52. Lose the Rev 4s. Definitely costing you top end. You don't need any hole shot help with that power. Mirages would be better. Don't use your Bennetts for anything but load balancing when necessary. Change your antifouling to something that can be burnished or designed for go fasts.
 
Thanks for the replys

i will do some more testing and see how I get on

With 9 adults aboard when I was running it in a quick blip showed 58.5mph on the gps no trim but with just 2 in you can be flat out and trimmed for a few mins and I think my max was 52mph

I have just antifouled it with the international Vic offshore so hopefully that's ok

Shame you can't see the vid it's like days of thunder lol

Cheers
Si
 
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