PaulGooch
Well-Known Member
In all reality though, with twin 107's it really doesn't matter what the props are doing, as long as they are rotating lol
Enfield z-drive
- Thread starter topcat1
- Start date
MapisM
Well-Known Member
Dunno which hull shapes you're talking about.
I assumed we were talking of plain V hulls, in which case the pressure below the stern is higher with the props spinning out, because you have a slightly higher percentage of the prop pushing down, compared to the other side which is pulling down.
And it's the other way round with props spinning in - that's why they're considered to improve bow lift.
The bow lift created by the thrust is a completely different animal, which depends mainly on the hull characteristics (and obviously on the amount of thrust), but it's unaffected by the way the props spin.
moonraker 36
Well-Known Member
i'm with you paulgooch.
were talking about aboat that will be lucky to see 10knts with a following tide.
were talking about aboat that will be lucky to see 10knts with a following tide.
MapisM
Well-Known Member
Point taken, we went a bit o/t with the stern/bow lift debate.
But since the props spinning outward make sense first and foremost to improve maneuverability, maybe that is of interest for any boat, innit?
But since the props spinning outward make sense first and foremost to improve maneuverability, maybe that is of interest for any boat, innit?
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PaulGooch
Well-Known Member
I had with with twin Peugeot XUD9s and it was slower than a slow thing going slowly, 8 knots backwind. Bit of a lump and the tide against you she was easily down to 4 or so. Good solid boat though.
oldgit
Well-Known Member
Pix
Project 31
Princess 32
from 25 years of Motor Cruisers ibsn0-7-3459-6
Project 31
Princess 32
from 25 years of Motor Cruisers ibsn0-7-3459-6
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tichmarshjohn
Active Member
princess 32
Hi my 32 has twin 75 hp volvos with 270 out drives.NOW I AM PI****T OF The best i ever got was 11.9 knots off Orford Ness with a clean hull & 5 knot tide up my stern.Wats wrong i have rebuilt the engines &. injectors, if i spend any more. money on different props my wife will leave me.Now you tell me i should be geting 14 to 20 knots with twins Please tell me i have missed something very simple. Ps wy wife is 7st wet will it help if she goes over the side.
Hi my 32 has twin 75 hp volvos with 270 out drives.NOW I AM PI****T OF The best i ever got was 11.9 knots off Orford Ness with a clean hull & 5 knot tide up my stern.Wats wrong i have rebuilt the engines &. injectors, if i spend any more. money on different props my wife will leave me.Now you tell me i should be geting 14 to 20 knots with twins Please tell me i have missed something very simple. Ps wy wife is 7st wet will it help if she goes over the side.
PaulGooch
Well-Known Member
No chance of getting any more. You did well to get 11.9 knots. Hull speed is less than 8 knots through the water. SOG is hull speed plus or minus the speed the water is moving. Only way to exceed that is to get it on the plane. Not a cat in hells chance of getting a 32 to plane on four pot engines. Unless i'm mistaken, they will only plane with the 6cyl engines.
tichmarshjohn
Active Member
princess 32
Thanks Paul i ithought as much.Got to find a way to tell the wife i want to re engine.I am thinking putting a pair of Peugeot 2.5 turbos in i have been told Lancing Marine will supply a kit to cool the turbos and my existing manifolds ect will fit this engine.Got to do some more reserch on this but open to any advise.John
Thanks Paul i ithought as much.Got to find a way to tell the wife i want to re engine.I am thinking putting a pair of Peugeot 2.5 turbos in i have been told Lancing Marine will supply a kit to cool the turbos and my existing manifolds ect will fit this engine.Got to do some more reserch on this but open to any advise.John
oldgit
Well-Known Member
"11.9 knots off Orford Ness with a clean hull "
If it cheers you up my P33 has never done better than 17knots @ 3300 rpm 2 x 135hp with outdrive and that was 10 mins after going back into the water with new A/F and rubberware change and not much stuff on board.
If it cheers you up my P33 has never done better than 17knots @ 3300 rpm 2 x 135hp with outdrive and that was 10 mins after going back into the water with new A/F and rubberware change and not much stuff on board.
Divemaster1
Well-Known Member
Support this one ... the MD21's with 270 drives, would perhaps give 12 - 13 knots Max when new, lightly loaded, in salt water and a massive helium ballon in the cabin....
Got a neighbour in the marina who have fitted a single reconditioned four pot 110hp ...AD30 and duo prop drive.... He gets about 12 - 15 knots out of the boat.... but just isn't enough to get her holding on the plane unless WOT.... to comfortably get 15 knot plus cruise out of this hull, I think you need a single 160 hp of reasonably modern engine, or something like two 130 hp six cylinder TMD40 from the late 70's, which should make her cruise around 18...
Got a neighbour in the marina who have fitted a single reconditioned four pot 110hp ...AD30 and duo prop drive.... He gets about 12 - 15 knots out of the boat.... but just isn't enough to get her holding on the plane unless WOT.... to comfortably get 15 knot plus cruise out of this hull, I think you need a single 160 hp of reasonably modern engine, or something like two 130 hp six cylinder TMD40 from the late 70's, which should make her cruise around 18...
PaulGooch
Well-Known Member
I'd still be a little doubtful they'd be up to the job, at 103bhp. I think it'd be touch and go and if she get get out of the hole i think she'd only stay up at WOT or close to. If i was going to re-engine a 32 i'd have to be looking at 6 cylinder engines if i was using older lumps. I'd want at least 250HP from twins.
PCUK
Well-Known Member
My old Senior 31 could manage ten knots with twin 4107s although they did crack the heads, break the crankshafts and perforate the bores at regular intervals.
Dave_Seager
Well-Known Member
I have twin AQD32A/270 engines and drives in my Princess 32. These are the 6-cylinder Indenor engines rated at 106 hp.
Lightly loaded and in calm conditions she will do 16 knots flat out. In cruising trim she will still plane at about 14 knots but requires maximum power so we only use it for short periods and normally settle for cruising at around 10 knots.
If you want proper planing performance you would would probably need more power or less weight. More modern engines tend to have a better power to weight ratio so you might not need very much more power.
A friend had a Princess 32 with the 4-cylinder AQD21A engines. These would never get the boat onto the plane although they are lighter than the AQD32As.
Lightly loaded and in calm conditions she will do 16 knots flat out. In cruising trim she will still plane at about 14 knots but requires maximum power so we only use it for short periods and normally settle for cruising at around 10 knots.
If you want proper planing performance you would would probably need more power or less weight. More modern engines tend to have a better power to weight ratio so you might not need very much more power.
A friend had a Princess 32 with the 4-cylinder AQD21A engines. These would never get the boat onto the plane although they are lighter than the AQD32As.
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AndieMac
Well-Known Member
I remember the old Princess Alf, from last year, moored on the inshore berth, port-side to.
macnorton
Well-Known Member
Only if she takes the cooker, water tanks, cushions, bulkheads, food ect with her.
Mine has twin 107's and i did get the factory quoted 12 knots once, with a following tide and running very light. but in the rest of the 8 years I have owned it the max has been 10 but I rarely reach 8 knts.
I think the factory quoted speeds should be concidered factory hipe, look at the wording (speeds of 16 or 17 knots are possible) anyway why race? you will only spend longer at the other end waiting for the tide! and this boating lark should be about relaxing and not having your spine bashed by every wave and your eardrums abused!
moonraker 36
Well-Known Member
pair of 5.7l chevy lump's mercursier alpha 1 drives. job done!(520hp)
MapisM
Well-Known Member
If he has the room for the 350s, he could go for a couple of these more modern blocks as well, and get 800+ hps out of them!
Alphas wouldn't be good enuff though, but then again, I wouldn't want them on the 350s either.
tichmarshjohn
Active Member
Princess 32
I agree boating is all about relaxing & enjoying the trip We have crused the East Coast up as far as Hull & the Thames as far as Windsor.Its just at times its nice to be able to push on if the weather is closing in.I would very like to go Dutch but feel 8 knots is taking a bit of a chance,i know the yachties do it .Thank you all for your input.I sometimes think it would cheaper to change her, but i seem to have got attached to the old girl just like the wife John
I agree boating is all about relaxing & enjoying the trip We have crused the East Coast up as far as Hull & the Thames as far as Windsor.Its just at times its nice to be able to push on if the weather is closing in.I would very like to go Dutch but feel 8 knots is taking a bit of a chance,i know the yachties do it .Thank you all for your input.I sometimes think it would cheaper to change her, but i seem to have got attached to the old girl just like the wife John
moonraker 36
Well-Known Member
If he has the room for the 350s, he could go for a couple of these more modern blocks as well, and get 800+ hps out of them!
Alphas wouldn't be good enuff though, but then again, I wouldn't want them on the 350s either.
i have an 18ft s/boat running a mercrusier 5.7l tuned to well over 340bhp on a standard alpha 1 drive with zero problem's handles the power no prob's.
but it was light harted when i suggested the v8's