400hp 6.2m sharkcat

[drg001]

I have recently blown up a 150hp salt water series yamaha on my shark cat (6.2 metre Rebelcat), thats the bad news, the good news i am now running a pair of low hour 200hp optimax's. Here goes the dumb questions. The yamaha's when pushed would do 86klm/h (gps) @ 6400rpm running 17 pitch stainless props. I intend on buying a pair of Mercury Enertia X7 alloy props 21 pitch, taking in to consideration i have increased the pitch by 4 degrees and i now have another 100hp will this cat do the ton / 60mph. And no i will not be running these motors past 5800rpm

[Wahoo]

I have recently blown up a 150hp salt water series yamaha on my shark cat (6.2 metre Rebelcat), thats the bad news, the good news i am now running a pair of low hour 200hp optimax's. Here goes the dumb questions. The yamaha's when pushed would do 86klm/h (gps) @ 6400rpm running 17 pitch stainless props. I intend on buying a pair of Mercury Enertia X7 alloy props 21 pitch, taking in to consideration i have increased the pitch by 4 degrees and i now have another 100hp will this cat do the ton / 60mph. And no i will not be running these motors past 5800rpm

HI DRG
have a chat to Ken Reeves https://www2089.ssldomain.com/propgo...ent/index.aspx

the Enertia props are a bit funny to work out
i was running a lazer ll 19p and WOT was getting 5750rpm 52mph
changed to a Enertia but still 19p WOT 6000rpm 55mph
i ordered a 18p which should be here mid nextweek, this should get my revs to where i want them

the good thing about merc props is you can keep swaping the props till you get it right
make sure you dont scratch / mark the props thou
i put up a thread a few weeks ago and posted a few pics on the laser ll and the Enertia props, both 19p and yet both very different looking
give Ken a e mail he is very helpfull


Daz

[Kerry]

....will this cat do the ton / 60mph

Do you really want to find out ????????????

[OPTI]

hi wahoo,yes should do 60 mph easy,i had a pair of 225 opti on my last boat 24 haines cat,it ran 64 mph with 21p on the limiters.i would try a pair of mirage 21p by 14 &5/8 dia the mirage is a better bow lift prop,i would also consider the new revolution 4 these give stern lift as well as bow lift but might not lean the boat over as much during cornering .stick with the larger diameter 14 & 5/8 on both types i think you will be happy with the outcome.
regards opti

[Noelm]

got the same boat, and if you prop them correctly I reckon you will be pretty close, had an old 23 sharkcat with 275's and it easy hit 60 the guy that built your boat, Barry Lawrence is quite a nice guy and will give you all sorts of info about it, they had two different types of pods on them as well , by the way, how is the stern with that much weight?

[fishingrod]

Are you asking a question (for advice) or just making a statement on how fast its gonna go?

Ive run a 7m SharkCat with twin 175hp Saltwaters. Im pretty sure it was on the bog standard factory props. Saw a EASY 44-48 knots (via GPS) with a full belly of fuel. Had seen 52knots with full tanks, a bit of trimming and a decent stretch of straight water.

I was never comfortable driving it over 35-40 knots in the river or calm offshore days. It just felt like it was a lethal weapon and i shuddered when i thought what type of accident it could cause. (EG: a tinny pops out that you didnt see and you have virtually nil chance of a emergency manourver. You could not tell investigators you were travelling at a safe speed)

Where as at the helm of a Signature 1750R runabout at 40 knots it felt a flightly but more in control as the boat is smaller and more agile.

I just dont want to see anyone get hurt in the need-for-speed.

Rod

[Noelm]

not trying to tell you how to set it up, BUT make sure you can at least get to 5,800RPM, regardless of the size props you choose, you do not have to run it there, but it must be capable of max RPM (whatever that is on your motors) especially on a Cat as they will "lug" a motor and cause early failure (maybe what happened to your other motor?)

[Noelm]

nope, sorry,just reread your first post, your old motors would go to 6,400RPM so no lugging there!!

[Wahoo]

not trying to tell you how to set it up, BUT make sure you can at least get to 5,800RPM, regardless of the size props you choose, you do not have to run it there, but it must be capable of max RPM (whatever that is on your motors) especially on a Cat as they will "lug" a motor and cause early failure (maybe what happened to your other motor?)

what Nolem is saying here is correct, WOT on this Opti is 5750rpm, set your props to at least get 5650rpm WOT

Daz

[wessel]

Are you trying to compensate for something?



W

[drg001]

Do you really want to find out ????????????

91klm/h @ 5300 rpm in choppy conditions with a handful of revs left in her, so yes i guess i'd be interested to know. thanks.

[drg001]

[quote=Noelm;651244]got the same boat, and if you prop them correctly I reckon you will be pretty close, had an old 23 sharkcat with 275's and it easy hit 60 the guy that built your boat, Barry Lawrence is quite a nice guy and will give you all sorts of info about it, they had two different types of pods on them as well , by the way, how is the stern with that much weight?[/quote It sat low with the 150's and it's a fraction lower with the opti's so i'm just more aware of raising the donks when we come to a stand still and i would probably put some tape over the exhaust outlets if i was leaving her in the drink overnight. cheers. ]

[drg001]

Are you trying to compensate for something?



W

yes, except my motors came off a much larger boat so there goes your theory cheers.

[drg001]

Are you asking a question (for advice) or just making a statement on how fast its gonna go?

Ive run a 7m SharkCat with twin 175hp Saltwaters. Im pretty sure it was on the bog standard factory props. Saw a EASY 44-48 knots (via GPS) with a full belly of fuel. Had seen 52knots with full tanks, a bit of trimming and a decent stretch of straight water.

I was never comfortable driving it over 35-40 knots in the river or calm offshore days. It just felt like it was a lethal weapon and i shuddered when i thought what type of accident it could cause. (EG: a tinny pops out that you didnt see and you have virtually nil chance of a emergency manourver. You could not tell investigators you were travelling at a safe speed)

Where as at the helm of a Signature 1750R runabout at 40 knots it felt a flightly but more in control as the boat is smaller and more agile.

I just dont want to see anyone get hurt in the need-for-speed.

Rod

Rod my theory is the higher the top speed the higher the cruising speed so speed goes up and range improves?

[drg001]

nope, sorry,just reread your first post, your old motors would go to 6,400RPM so no lugging there!!

yeah but that was running 17 pitch ss props on 150 yamahas