Shark Cat 2800 engines

[SeaSaw]

Went for a fish in a Shark Cat 2800 on the weekend. Nice boat but conditions were so good I didn't get to see how it performed in the rough.

The owner is considering replacing the engines. It is currently powered by a pair of 200hp Yamaha outboards. I spent a fair bit of time driving it and I felt it could do with some more horsepower, but I am not use to such a big heavy boat. The 200's got it up OK. It was cruising at 17 to 18 knots @4200 rpm with these engines. To get the best out of it, my thinking was that it should be able to get 4 or 5 knots better at that rpm, so another 100hp would be good. i.e a pair of 250's. I reckon a boat of this caliber should be able to cruise at 25 to 30knots at cruising rpm - around 4500.

I don't have any other info, like top speed and rpm as the owner didn't like to run the engines any harder. The boat is a cabin setup, no flybridge, carries about 800litres of liquids.

So anyone with experience in the 2800 shark cat, can you advise what engines they typically have in an outboard setup and what to expect in terms of speeds and performance? I assume the weight of 4 strokes in a big cat like this would be OK.

Thanks,

Mark

[Grand_Marlin]

G'day Mark,

A lot of them had 200's on them.

Beats me why they didnt have bigger, as there are plenty of 23's that have 200's on them as well.

I suppose though, the 28's are a different feeling boat ... set them up at cruising speed and they will sit there all day in any conditions... whereas the smaller cats are more lively to drive - using the throttles a lot more.

Weight of bigger outboards wont hurt these big cats in the slightest.
The 28 I spent time in had twin volvo diesels in it, and it performed very well.
Diesels are way heavier than any outboards will ever be.

You just have to remember that the 28's are more of a cruiser, rather than a sports boat, so therefore the extra weight / power wont hurt it at all, but will it give it much more of an advantage?

Cheers

Pete

[snelly1971]

Our 27 foot Noosa cat...work boat is fitted with twin 225 yammie 2 s and by memory it approx 30 knots at 4400 rpm....

[snelly1971]

Ps...top speed is about 80-83 km /h if that helps...running 21 pitch props

[SeaSaw]

Thanks Pete, it did have that cruiser feel about it.

Are you suggesting that the extra power will end up costing more in fuel and a larger up front capital cost for little iimprovement in performance? I was thinking it should be able to get the sort of performance that Snelly is getting, but I would hate to suggest the guy spend the extra money and then find out there in no performance advantage.

Is it more about prop diameter and pitch with these big cats?

Mark

[snelly1971]

Hi Mark...i would only be guessing the amount of km travelled ....but the difference between the two cats here...one fitted with twin 225 yammie 2 strokes and the other twin 250 suzuki 4 strokes doing the same trip and working the same amount of time is approx 160 liters in the suzukis favor..it is something worth considering??

[SeaSaw]

Snelly, He will almost certainly go for a 4 stroke to get the fuel savings. I like the idea of the lower gear reduction and the bigger diameter pitch of the Suzuki's .... seems to be a good match for big heavy outboard powered boats like this cat.

Thanks for your replies.

Mark