Any advice on this design?

[Danielsan]

Hi all,

Have been drawing this cruiser for the past weeks.
As a result i get a 3000Kg boat = displacement 3000 kg or +/-3 cubic meters, LOA 7.42 meters, LWL 6.20 meters, draft 42CM?!?

I hope I get this right?
anybody can give me some advice? I think the boat isn't going to be deep enough in the water? Any idea about horsepower, pitch, blades, is welcome?

My first idea was putting in a car engine kind of BMW324TD, second idea BMW525TDS now I did end up with a 6cyl perkins +150HP but also a lot heavier.

Did draw this thing in solid works, before I found out about maxsurf it was a bit pain in the @$$

greetz,

Daniel Peeters

[yipster]

i sort of like that zipped bmp drawing...
your asking a lot i cant answer but at first glance your figgers look about correct exept for the power.
if you want that 3000 kilo drawing to plane i estimate at least 250 hp.

[Danielsan]

Thx for the prompt reply.

The engine is the only thing that keeps on my mind, once that's cleared, I can begin printing out the cut-outs and puting them on wood(MDF) to cut them out,...

Greetz,

Daniel Peeters

[Kreso]

Hi,
required power for planing you can check here :
Boat Design Forums > Design > Software
and than look for:

Savitsky Power Prediction

Kreso

[Danielsan]

Thx Yipster and Kreso (so I put it back on top)

The hp prediction seems to correspond even worse it should be higher, around 320hp

Honestly I expected much less, around 150-180hp as I wanted to put in a car engine. Now I still can and probably will do but it will be harder to find in diesel,...

Did post some other questions on other forums, like what with HP/torque for diesel and gas, what kind of prop, what kind of rpm?

any hints?

Greetz,

Daniel

[RANCHI OTTO]

According my own estimation system the speed vs power are as follows for a boat with a displ. of 3.1 t :

Vk > 24 > 160 BHP
27 200
31 240

RANCHI OTTO

[Danielsan]

THis thread is dead now, this was one of my first posts when I discovered this forum.
As in this moment I have done some redesigns and some more accurate estimations.

I end up wit a 7.42m x 2.55m x 0.40m draft boat. displacement of around 2,4ton. I dont have other numbers here.
http://www.boatdesign.net/forums/att...achmentid=3107
http://www.boatdesign.net/forums/att...achmentid=3106
http://www.boatdesign.net/forums/att...achmentid=3105

any more hints are allways well apreciated

greetz,

[yipster]

speed vs power are as follows for a boat with a displ. of 3.1 t :
Vk > 24 > 160 BHP
27 200
31 240

is that shaft hp?
our 3.1 t 27 ft sea ray sundancer with 2*220 hp EFI / BIII doesnt come out of the water on one cr prop...
on 2 engines wot fully loaded she goes 38 knt gps

[RANCHI OTTO]

If you have a look on my web, you will see the boat named "REFOLO" (video and pic's). This boat has an ASD hull shape and the performances were as follows:

1 x 205 BHP > 43 knots (Volvo)
1 x 225 BHP > 53 knots (Suzuki)
1 x 25 BHP > 25 knots (planing condition)

The hull shape ASD helps the boat to reach the planing condition in short time. Your boat with such power has perhaps the l.c.g. very closed to the transom. With the ASD hull shape the additional after water volume reduce the static long. trim angle and so doing the boat run paralel to water at low speed. (see video of the boat)

RANCHI OTTO

[yipster]

Your boat with such power has perhaps the l.c.g. very closed to the transom.

youre right OTTO, and sorry for my off data. didnt realise it makes that much difference and keep forgetting the new l.c.g. of our boat after the refit with EFI's, risers, BIII's. i see your point(s) and thanks for reminding me, i'll have to shift weight forwards (and get a new prop)

[RANCHI OTTO]

Dear Yipster,

I've found a picture of the "REFOLO ASD" equipped with 1 Johnson 737 developping 25 hp.
As you can see the boat is in full planing condition.

RANCHI OTTO

[RANCHI OTTO]

I've calculated the speed for a boat with displ. = 3.1 t and 2 x 220 hp.
I find a top speed of 40 knots that is not far from your 38 knots.

RANCHI OTTO

[RANCHI OTTO]

Dear Yipster,

The boat of Danielsan has 1 shaft + propeller + rudder. So I've understood.
For outboard engine the forecast is :


Vk>15> 160 hp
Vk>20> 200 hp
Vk>22> 240 hp

RANCHI OTTO

[jfblouin]

Very interresting design

What is the deadrise angle for the new design?

[yipster]

OTTO, much appriated and yes i like that ASD arrow bottom too...