Advice sought on performance of Ford 145hp diesel

[Duster]

I am currently chosing between two similar US built sports/fishing boats , whichever one I chose , I will have to convert it to diesel as waterside petrol is unavailable in my boating area.
The smaller one is 21.5ft , weighs 1.6tons and is offered with a choice of 3.0l (135hp) or 4.3 (220hp) Mercruiser petrol.
The larger is 23.5ft weighing 2.1 tons and is offered with the 4.3l (220 hp) or 5.0l (260 hp) engines.
Both are fitted with the Mercruiser Alpha drive and have a similar deep v hull.
I have spoken to Lancing Marine re their 2.5l (145 hp) Ford . They were extremely helpfull and suggested that I should expect around 27/29 knots from the smaller boat and 23/24 Knots from the larger.
My preferance is for the larger boat - for more room and a better ridebut I am concerned as to how well it would perform / handle - would it struggle to stay on the plane? The speed would be adequate for me as long as the boat was not struggling. The smaller boat would obviosely be fine with that amount of power.
To go to a more powerfull diesel would mean a big increase in weight and cost plus the Alpha drive may need changing for a Bravo - even more weight and cost.
Does anyone have an opinion or better still experiance of a 23/24 ft boat of around 2.25 tons with the Ford diesel fitted.
Regards mikej

<hr width=100% size=1>

 

[stamfordian]

Hi Mike,
i run a ford 2.5 normally aspirated ford(75hp) in a 23fter though an out drive,with a semi-displacement hull... flat out she does 12knots in semi diplacemant mode and somtimes falls over to plane(currently fitting trim tabs to provide lift to the rear so planes at low speed).So Lancing figures seem to be in the ballpark.
Hope this helps a little(pictures of boat via link below)

<hr width=100% size=1><A target="_blank" HREF=http://www.arweb.co.uk/argallery/stamfordian>http://www.arweb.co.uk/argallery/stamfordian</A>

 

[Duster]

Thanks Trevor , that sounds very promising. With a boat of similar length and weight to yours ,but double the power ,it seems as if I should hold the plane comfortabley. Lancing were certainly helpfull and seemed proffesional .My existing 15ft boat seems to plane comfortably from 16 knots I was just unsure of the drop off speed of a longer boat.
Regards mikej

<hr width=100% size=1>

 

[tico]

Hi
I've got 2 Lancing 140hp units in my 26' 3.5ton cruiser, so having had the experience, i wd say that Mike knows wot hes talking about.
1 engine shld give about what he says, in terms of whether it'll stay on the plane, will depend to some extent on the hull form, but answer is probably fine.
BTW, the characteristics of the diesel mean that it stays up better as the ooomph is more constant (greater torque) and allows it to power thru waves rather than being knocked back by them.
Would recommend that you discuss with Mike the prop needed, thats the critical bit, PS his prop program is spot-on

<hr width=100% size=1>Been there, done that, got the oily T shirt

 

[martynwhiteley]

Don't overlook the Mercruiser D120.

I'd bet good money that if your boat was fitted with either the D120 or the Ford 145, the D120 would not be the slowest. The D120 only weighs about 200kg, and one in my 3.5T 27ft cruiser does 20 knots and stays on the plane no prob.

The D120 will also be more economical, quieter, and far less smokey I suspect. There was a new one advertised recently for less than £5K plus vat. They are matched to the Alpha drive, so no prob there.

It's well documented that the D120 will ALWAYS outperform Merc's own 3 litre 135hp petrol. At smaller engine sizes, the advantages of higher torque and flatter power spread tip the scales very much in diesels favour. If I'd fitted the 135 petrol, I doubt whether my 27 footer would lift onto the plane.

<hr width=100% size=1><font color=blue> <A target="_blank" HREF=http://www.mboat.org>http://www.mboat.org</A></font color=blue>

 

[Duster]

Hello Martyn,
Your reply, based on practical experiance, is very encouraging . It would appear that either boat would be fine with either the Ford or the D120 . The smaller of the two boats is now offered with the D120 but I am unlikely to find one in a used boat yet ( particularly as I am planning to do a personal import from the US). The main reason I favoured the Ford was the extra 20ish HP and the fact that it was a 2.5l rather than a 1.7l. Based on your findings I will certainly consider the D120 especialy as it would be an easier swap.
Thanks again mikej

<hr width=100% size=1>

 

[Duster]

Thanks Tico ,
I had no doubts about Lancings info, they do seem very proffesional, it was just I was unsure how well the boat would plane at that speed. Martyns reply seems very reassuring.
Regards mikej

<hr width=100% size=1>