Propeller tunnel: yes or no?

[marcochi76]

load is % fuel used compared what’s available.
So if you divide the 193 into 240 ( est ? burn at WOT ) it equates to spot on near as dam it 80 % .
Thats about right .80 % load .

If I correctly read the MAN charts, the absolute fuel consumption at full load (red curve) at 1900rpm is approx 200 l/h.
Thus my 95% load estimation at that specific RPM.
Yes, it is 80% from max load at max RPM. But I was expecting that at a specific RPM, the load on the engine to be lower.





For example, my V39 at fast cruising speed of 27 knots at 3000 RPM, burns 51/52 l/h per engine.
The max fuel burnt at 3000rpm is 61 l/h.
This means that at 27 knots, by engine is at 51/61= 83% load for that specific rpm.
This tells me that the engines are running smoothly and without too much stress.

 

[marcochi76]

So think carefully over the 2 vs 3 + cabin conundrum…….you are left funding the berth + maintenance + and as you already have seen @ potential 380 L / h fuel bill cruising .

yes, 55 foots is certainly too big.
48/50 is to me is the correct size as you can find it with shafts and a nice full beam cabin. I do not need at all the third cabin.
Princess V52 is a good example but it is a BIG boat.

Pershing 50 is a nice alternative, but the layout too old fashion. It seems to run better with Shafts vs SD.

Rizzardi 48in or InFive seems a good contender. But I think 50foot is on the lower size limit for Surface Drives.

Pershing 5x very nice. I spoke with Pershing broker at Cannes and they confirmed me that they abandoned the Arneson option as it didn't run well. It works better with IPS.

 

[marcochi76]

Coming back to the topic discussion:
the Pershing 46, which I consider a high capable yacht, also has propeller tunnels:

 

[Sticky Fingers]

Coming back to the topic discussion:
the Pershing 46, which I consider a high capable yacht, also has propeller tunnels:

View attachment 165577

That’s a great boat

 

[jfm]

Coming back to the topic discussion:
the Pershing 46, which I consider a high capable yacht, also has propeller tunnels:

View attachment 165577

Very nice boat. Perfect 10/10 chocks too

 

[Bouba]

Coming back to the topic discussion:
the Pershing 46, which I consider a high capable yacht, also has propeller tunnels:

View attachment 165577

To be fair...they look like very shallow tunnels

 

[Portofino]

To be fair...they look like very shallow tunnels

Yes they don’t look like from that pic like full tunnels the topic of this thread .I mean 3/4 enclosed or at least 1/2 buried props .
I d call those semi tunnels but they are very shallow the props dangle nicely .
Note no added afterthought fixed flaps or Humphreys .A good sign .

Thats a great boat and seems to thus far best fit the Ops criteria .

 

[PowerYachtBlog]

The Pershing 46 is an extended 43 with a third aft cabin presented in 2005 she is one of the last aft cabin open cruiser or yacht from Italy.
A layout pioneered by Pershing with its first model the 45, which became a trade mark of the Italian open yacht after that 1985 revolutionary model.
She rides insanely flat, flatter then a 43, but is a bit of a wetter ride, unlike the 43 which is dry as you can get.
She reaches about 36 knots and was available with surface drives (I think only four made out of about forty). About 42 with Sds and Man R6 800hp.
Both 43/46 had smaller tunnels, a bit smaller to those of Fairline/Princess, and smaller to those of Sunseekers.
The Sunseeker one about 40% of a circle, FairPrincess would be about 30%, and Pershings are about about 20%.

If you could stretch your budget 10% mire I would always look at the 50 with line shafts which is a really great boat in its class.
Better then anything in its class, and worth to buy for the turning passenger settee in the large dinette.

 

[marcochi76]

PYB: Thanks for the detailed info. And yes the P50 seems to be a great boat!

These are the tunnel of the Princess V52:

 

[Parabolica]

My Pred 60 has tunnels (just stuck my head under the platform to check), and whilst i’ve been very happy with my boat, having now read this thread i’m feeling like i’ve been had over and must have bought a pig in a poke

 

[Portofino]

My Pred 60 has tunnels (just stuck my head under the platform to check), and whilst i’ve been very happy with my boat, having now read this thread i’m feeling like i’ve been had over and must have bought a pig in a poke

How s it ride ? Can you see out safely sat down on the helm seat ? Or do you have to stand up always when it’s on the plane , step on a shelf or box to see over the bow ?

If you can drive it sitting ( see out Fwds enough) then it’s ok imho .

I ve taken the liberty of assuming you don’t have a December seasonal job in pantomime along with 6 others of similar stature .

edit = stick a bowl of water on the cockpit floor and video it cruising .Post it on here nuff said !

 

[Parabolica]

How s it ride ? Can you see out safely sat down on the helm seat ? Or do you have to stand up always when it’s on the plane , step on a shelf or box to see over the bow ?

If you can drive it sitting ( see out Fwds enough) then it’s ok imho .

I ve taken the liberty of assuming you don’t have a December seasonal job in pantomime along with 6 others of similar stature .

edit = stick a bowl of water on the cockpit floor and video it cruising .Post it on here nuff said !

I can but then i am 6’8” so that’s hardly surprising. it doesn’t ride flat no, but is fine with the trim tabs deployed (non Humphrey’s).

i’ll do the water bowl test next time i’m out and see what occurs. Do i have to steal a dog though coz i dont have my own?

 

[Bouba]

I can but then i am 6’8” so that’s hardly surprising. it doesn’t ride flat no, but is fine with the trim tabs deployed (non Humphrey’s).

i’ll do the water bowl test next time i’m out and see what occurs. Do i have to steal a dog though coz i dont have my own?

6 foot 8 !!! are you the tallest forumite ?