selecting the best prop??

[Spaniard Racer]

Hi guys needs some advice please .
I have a 21ft marshan with a merc 200 and am running with a laser II 28p prop i also got given another laser II prop but a 19p just need some info in what they both do in respect of which is quicker and which gives me better acceleration? and maybe oan overall best to use??

did try and google but got lost in the calculations of it all

hopesome can help??

[baj666]

Originally Posted by Spaniard Racer

Hi guys needs some advice please .
I have a 21ft marshan with a merc 200 and am running with a laser II 28p prop i also got given another laser II prop but a 19p just need some info in what they both do in respect of which is quicker and which gives me better acceleration? and maybe oan overall best to use??

did try and google but got lost in the calculations of it all

hopesome can help??

ive got a 19 marshan and even my boat would be a little over propped if i banged a 28p on it and thats with a healthy XR2..the main problem with our boats is there is very little bow lift with these heavy boats so its harder to find a good prop combo..atm ime tooting about with a 23p high five which gives me a little over 60mph but can also give good holeshot and thats with a 4" set back and the case 1" below ..hth

[Spaniard Racer]

The marshan world is hard work!

sorry i ment that i have a 27p prop on at the moment and with that i got 50 mph with 2 of us in it so if i put on the 19p will it go faster top end or just accelerate faster with slower top speed?

[rob m]

Originally Posted by Spaniard Racer

The marshan world is hard work!

sorry i ment that i have a 27p prop on at the moment and with that i got 50 mph with 2 of us in it so if i put on the 19p will it go faster top end or just accelerate faster with slower top speed?

whats your rpm when flat out with the 27p on

[Spaniard Racer]

will be honest with you as it was the 1st time i got that sort of speed due to good weather conditions i didnt even think of looking at my revs just the speed

[baj666]

Originally Posted by Spaniard Racer

will be honest with you as it was the 1st time i got that sort of speed due to good weather conditions i didnt even think of looking at my revs just the speed

need to see what rpm the motors pulling... ime still thinking your a little over propped for a marshan

[NIC SURRY]

Originally Posted by Spaniard Racer

The marshan world is hard work!

sorry i ment that i have a 27p prop on at the moment and with that i got 50 mph with 2 of us in it so if i put on the 19p will it go faster top end or just accelerate faster with slower top speed?

you need to find WOT-Wide Open Throttle revs that your engine is designed for (say 6000 rpm) and keep going up in prop pitch until you find you don't reach that revs if you can only achieve 5500 rpm in flat water then you have gone too a high a pitch.I would have thought a 19P would give good acceleration but get to max revs too quickly ie slow top speed.Buy my 21P Offshore on E bay as it was a great prop on my Phantom 20 200 Hp XR2-I found a High Five scary at high speed-Hope this helps Nic

[Spaniard Racer]

many thanks for all your help guys and i know its not easy as you didnt know what revs i run at. taking the boat out sunday so going to stick on the 19p and see what that does to me but will be keeping the 27p with me incase i feel like getting some top speed but all depends on the british weather! many thanks again

[Cookee]

That is a huge difference in pro sizes, I would suggest you'll probably hit the rev limiter or over rev the engine with that prop, so be careful when you open it up!

[rob m]

Originally Posted by Spaniard Racer

many thanks for all your help guys and i know its not easy as you didnt know what revs i run at. taking the boat out sunday so going to stick on the 19p and see what that does to me but will be keeping the 27p with me incase i feel like getting some top speed but all depends on the british weather! many thanks again

i have a 26p reworked to a 25p or so i was told. i am looking to try a few props so if you want to lend for a lend i will do that. i have had a 19p on my phantom and was over reving. the sharp 19 i had was hard work to get it going i didnt try a lot with it as i got rid so i could get the phantom

[Spaniard Racer]

so i have just got back from a day out on the boat and have some info that might help with my question

I got 52 nots today at 5 Revolutions per minute with my 27 laser II prop with 2 of us.

is this good?

[baj666]

Originally Posted by Spaniard Racer

so i have just got back from a day out on the boat and have some info that might help with my question

I got 52 nots today at 5 Revolutions per minute with my 27 laser II prop with 2 of us.

is this good?

you have at least another 1000 rpm to achieve peak power it seems...try going down a pitch or two if your able to borrow and where is your gear nose in relation to the boat bottom..

[OCRDA]

No !!
Assuming you mean 5000rpm I would suggest you come down to a 23" laser or a small hub 24 or 26 you really need to be around 5800rpm at least

Bob

[Spaniard Racer]

thought as much!

will hunt a 23 down and give that a try kinda want a good top end and good acceleration

not asking for much am I

[scarab racing]

No you dont 'just' want good top end and acceleration you want to over take me................ whats it like only seeing my boat from behind with that diesel smoke in yer face............