Targa 34 performance

[Harpergreg]

Can anyone help
I have a targa 34 with kad 300s
Everything seems to be running sweet, but only getting 27knots at 3700 rpm
Instead of I’m guessing 37knots
I’m carrying a bit of stuff and 3/4 water and fuel. Anti fowl recently done.
It was on the Thames before i brought it.
Now on the Solent. Would props maybe be different?
Any help appreciated

 

[Harpergreg]

This was mine, and a pic of one for sale on the net

 

[volvopaul]

Can anyone help
I have a targa 34 with kad 300s
Everything seems to be running sweet, but only getting 27knots at 3700 rpm
Instead of I’m guessing 37knots
I’m carrying a bit of stuff and 3/4 water and fuel. Anti fowl recently done.
It was on the Thames before i brought it.
Now on the Solent. Would props maybe be different?
Any help appreciated

What size props do you have ? Seems very underpropped to me as it’s a 40 knot boat .

 

[Harpergreg]

What size props do you have ? Seems very underpropped to me as it’s a 40 knot boat .

not sure, i think i have a picture. let me see

 

[Harpergreg]

not sure, i think i have a picture. let me see

not sure, i think i have a picture. let me see

Pictures won’t load, but can’t see markings. What should they be, any ideas

 

[volvopaul]

Pictures won’t load, but can’t see markings. What should they be, any ideas

Should be stainless props the numbers are on the hub , Starts with aC

 

[petem]

Can anyone help
I have a targa 34 with kad 300s
Everything seems to be running sweet, but only getting 27knots at 3700 rpm
Instead of I’m guessing 37knots
I’m carrying a bit of stuff and 3/4 water and fuel. Anti fowl recently done.
It was on the Thames before i brought it.
Now on the Solent. Would props maybe be different?
Any help appreciated

Does sound like props.

How recently was the antifoul done?

 

[Momac]

Sounds like non standard props may have been fitted for use at the slower speeds on the river.

 

[ari]

Everything seems to be running sweet, but only getting 27knots at 3700 rpm
Instead of I’m guessing 37knots

Another vote for props being pitched for 'lower gear' running. Think of it like a car, should do (say) 100mph at 5,500rpm in top gear but in third it's getting the 5,500rpm but that only equates to 70mph. That's effectively what you are experiencing.

 

[stelican]

Are the props clean?

 

[Harpergreg]

Are the props clean?

YES,FEW LITTLE DINGS

 

[Harpergreg]

Another vote for props being pitched for 'lower gear' running. Think of it like a car, should do (say) 100mph at 5,500rpm in top gear but in third it's getting the 5,500rpm but that only equates to 70mph. That's effectively what you are experiencing.

understand what your saying, but not sure why I'm not getting up into the mid thirtys at them revs.

 

[Harpergreg]

What size props do you have ? Seems very underpropped to me as it’s a 40 knot boat .

c 6

 

[Harpergreg]

Does sound like props.

How recently was the antifoul done?

c6 stainless

 

[Harpergreg]

anti foul done 5 weeks ago, so pretty clean

 

[PaulRainbow]

understand what your saying, but not sure why I'm not getting up into the mid thirtys at them revs.

If you're not sure why you don't get into the mid 30's you don't understand what Ari wrote.

Lets say at 4000 RPM your car does 120 MPH in 5th gear, 100 MPH in 4th gear, 80 MPH in 3rd etc. Your boat will do 40 kts with the correct props, but if someone has changed them for smaller ones, or a different pitch, it's like changing down a gear, or two. The engines run at the same RPM, but the speed is slower.

 

[petem]

C6 are the correct props so that's not the cause.

 

[Harpergreg]

Must be geared differently in the leg maybe

 

[PaulRainbow]

C6 are the correct props so that's not the cause.

Could be re-pitched.

 

[Harpergreg]

Hopefully steel developments can sort it once i get them off.