how fast

lobbers · 08-03-2005, 08:51 PM

can anyone shed some light on what sort of speed i may get out of my yam 200 prov with 21" prop please

Burty · 08-03-2005, 09:00 PM

If the sequel is a light boat a 21" may be alittle on the small side but i recon you should see at least around the 60mph

Cookee · 08-03-2005, 09:04 PM

It depends on the gear ratio of the gearbox as well.

Gav · 08-03-2005, 09:04 PM

Quote:

Originally posted by lobbers
can anyone shed some light on what sort of speed i may get out of my yam 200 prov with 21" prop please

Not fast enough cockwipe!!

lobbers · 08-03-2005, 09:06 PM

so what would be a better size prop to use

Gav · 08-03-2005, 09:08 PM

Quote:

Originally posted by lobbers
so what would be a better size prop to use

two bladed Seagull prop..........worked a little

lobbers · 08-03-2005, 09:10 PM

and stiil you would be following

Burty · 08-03-2005, 09:14 PM

Quote:

Originally posted by lobbers
so what would be a better size prop to use

Whats your gear ratio?
what rpm is peak power on your engine?
how high you running? i.e where is your prop shaft in relation to the bottom of your transom?

lobbers · 08-03-2005, 09:22 PM

not sure of any of that just brought engine cos looked good and prop is about 4ft away as not fitted it yet wanted to get as much info as poss before so to get it right when fitting it

Burty · 08-03-2005, 09:28 PM

if it the same sort of spec as a 200 merc with 1.87:1 gears and you are looking for top speed thus sacrificeing a little on pull out by mounting the engine high you may see the magic 70mph but you may find you need around a 23" prop to keep the revs down but best thing to do is find out where peak power is then run it with what you got and see what revs you get flat out then prop up or down accordingly.

lobbers · 08-03-2005, 09:34 PM

ok thank i,ll have to see how she goes know where there is a 4 bladed phirana 24" prop

Gav · 08-03-2005, 09:37 PM

Quote:

Originally posted by lobbers
ok thank i,ll have to see how she goes know where there is a 4 bladed phirana 24" prop

Feck off!

:hot:

lobbers · 08-03-2005, 09:49 PM

now thats not being very sporting is it

Jon Fuller · 08-03-2005, 10:40 PM

I think the Yam's are lower revving than Merc's, topping at summat like 5500

Steve · 10-03-2005, 08:02 AM

Running a Yam Pro V 200 on the back of a Ring 21E with a Yam 23" prop & getting just under 70mph @ 5800 rpm.

Have tried a couple of 4 bladers & gain on pull out but loose a couple of mph at the top end.

Not sure how the weights of the boat compare though.

Cookee · 10-03-2005, 09:06 AM

If you put all the data into this - speed calculator you will be able to work it all out!

Thunderbird Racing · 10-03-2005, 02:59 PM

i was running my yam 130 at 6400 no problem this year after cutting the rev limiting cable.

FrenchPhil · 10-03-2005, 05:30 PM

Isnt there a speed calc out there with boat weight ? It definitly has an impact on speed.

Cookee · 11-03-2005, 09:24 AM

No because there are other factors involved such as hull design. The prop calculator will give you a maximum possible speed or if you know that the amount of slip but that's all.

BluFin · 11-03-2005, 09:52 AM

Quote:

Originally posted by FrenchPhil
Isnt there a speed calc out there with boat weight ? It definitly has an impact on speed.

Correction is made under the slip of the prop,
identical set ups but with differing weights will have differing slip percentages.

There are a lot of questions on props must post my excel spredsheet. er Damm!! must make it a zip first !!