Princess 30DS speed

[snowbird30ds]

I have recently aquired a princess 30DS with a pair of TMD41A's @ 150HP each and need some ideas of what speed I should get from it, I've given it a few full throttle runs and only had 16knots, both engines run up to 3900 as they are rated and sound properly under load so I don't believe there's any issues there but I would have thought nearer 20knots would be reasonable.
It has a bar keel added to the bottom (with beaching legs for drying moorings) as seen in the piccie below, I know it will be adding a fair bit of drag but would like an idea of how much difference it would make and wether it's worth taking it off.

 

[Latestarter1]

Jersey keel will cost you AT LEAST 4 knots and with about 140 proper hp on tap your 20 knots is not unreasonable.

 

[snowbird30ds]

Double post removed, oops.

 

[snowbird30ds]

Interesting that you call it a 'jersey keel' as it has spent time in jersey, do you know any more about it? I have a drawing but no company name on it.
It has the beaching legs to go with it as well but I doubt I will ever use them.

 

[Divemaster1]

Think that keel is playing havoc with your hull hydrodynamics .....and to reach full RPM dragging that stuff through the water, you may well not be on original propellers ... if you were, you'd be overloading the engines...

Here's one advertised as managing 21 knots with same engines and also with shafts...

http://www.yachtworld.co.uk/boats/1989/Princess-30-DS-2910953/Spain#.Vv0a2E8rLcs

 

[snowbird30ds]

I'm always a bit iffy about accepting quoted speeds when it's in sales pitches, they are understandably biased in their favour along with economy figures, I'm looking for info from current owners that are not on a sales drive.

 

[CX54WEK]

I doubt that boat ever reached 20 knots when it was new, never mind now with that keel addition.

A pair of 150's is never going to make a speed boat with a heavily built hull like that.

 

[Divemaster1]

I cannot say anything actual on the DS, but in the 80's I had an Apollo 32 with 2x120 hp on shafts... clean bottom and lightweight in the early spring before all cruising gear came onboard, she did 20 knots (high cruise at 16 fully laden... and measured over a 100 NM stretch, not GPS) .... and the neighboring DS30, with 2x150's on shafts was faster than us... So whilst not being an owner, I do have some real life experience with the DS30 Boat/hull/engine configuration.... but not a keel like yours though... ... which will create significant drag both in direct resistance in increased surface, and a non-smooth water flow between the supports.... and I'd also hazard to say that it is un-likely that the propellers are getting smooth water with the aft keel support V disturbing the water right in front of the propellers.

In accordance to the bible "25 years of motor-cruisers 1960 - 84", by Alex McMullen, she did around the 25 know mark with 2x130's AD40's ... so 20 + with 150's on shaft is very probable....

 

[snowbird30ds]

I think it may well come off next winter and maybe add an inch of pitch to the props as it revs to the max with keel on so probably over-rev without the extra drag, hopefully it will get a good run round to wells from gt. yarmouth on the late may BH so see how it handles.
It has to be better than slogging around at 6-7knots in the old tub.

 

[CX54WEK]

We might well see you at Wells that week

 

[snowbird30ds]

We might well see you at Wells that week

I know, Luke told me....
Used to be the old RLM31 'Leo Magill' @ 6 knots.

 

[CX54WEK]

16 knots should feel like your flying compared to Leo

 

[myultrasound]

Hi, Tamd41 engines are 6 cylinder 200hp.. Not 150hp

If that is the case, you should be pushing 30knots.. My boat has AD41's in a Princess riviera and and does 30knots with ease.
Are you sure of the engine model? AD31`s are 150hp..

I see your hull is clean, so no problem there.. My advice is get the boost checked on both the turbos..


Thanks!

 

[snowbird30ds]

Mine are TMD not TAMD, no aftercoolers in the system, I'd love 30 knots but with 100hp less I doubt it will happen, especially with the spare metalwork underneath.
I think the decision has been made that the keel is coming off.

 

[myultrasound]

Mine are TMD not TAMD, no aftercoolers in the system, I'd love 30 knots but with 100hp less I doubt it will happen, especially with the spare metalwork underneath.
I think the decision has been made that the keel is coming off.

Ah yes, my mistake.. Yes remove that metal from underneath.. Also you could try some extra big trim tabs.. If you can get it to 20knots.. Then that is respectable enough and will be planing perfectly..

Good luck

 

[QBhoy]

Is it possible the propellers have been changed for a lower pitch to give better or easier slow speed cruising and manouverability on canals or water ways ?