glastron sx195 5.0 merc

[lucky7]

hi all and happy winter. i am a nube at prop science, maybe someone can piont me in the right direction. i have a 19.5 foot sterndrive, came with a 21" aluminum prop, runs right to the top of recomended rpm, maybe 100 rpm above with just me in the boat. {4900} 56-57mph on the gauge. with max load she would only pull up to 4200. issues i would like to address in my next prop : is it possible to keep the boat on plane at a lower speed with a different pitched prop? seems to fall off plane around 19 mph, with the kiddies kneeboarding and learning to ski, a slower plane would be nice. would a 4 blade prop be good for this? thanks for any insight you can give.
jay in snowy nh.

 

[Bondo]

Re: glastron sx195 5.0 merc

Ayuh,...

I'd leave the Prop alone,+Add a set of Smart Tabs.....

 

[Tail_Gunner]

Re: glastron sx195 5.0 merc

Trim tabs will lower your planing speed as Bondo suggested above....However they have a very negative effect if you choose to wake board.....They perform so well your left with little or no wake.. i should add Nauti trim tabs does have a system which will allow you to mechanicaly unlock them but then your right back to where you started..

Stilletto makes a 4 bladed line of props called BayPro 11, a 18 pitch will provide you with all the low midrange tourqe and hole shot you can get from a prop...there are very good props....A 20p will probably be a bit to much when your under a heavy load.....but with 2 people it would be a kick.

Wha type of drive...Merc or Volve...

Just a thought....if your boat can achieve 55mph plus and the boat does have a 20 degree v hull trim tabs might be a very good ideal....At those speeds with deep v and the lifting quality of baypro's you might experience chine walk at WOT...the tabs will help with the side to side wobble...been there done that...and at lower or wake boarding speeds Nauticus does make a system for disabling them...the best of both worlds....Now the 18 will probably not get you there but the 20....will take you to at least you old speed and probably beyond due to the fact of less wetted surface...yes the baypros do lift a 19' 3000lb boat up that high..

 

[lucky7]

Re: glastron sx195 5.0 merc

its a merc alpha 1 gen2.
would a 4 blade prop or any prop affect minimum planing speed?

 

[Tail_Gunner]

Re: glastron sx195 5.0 merc

Yes quite bit if you use a Stilletto baypro 11 in a 18p which would be the correct pitch for carryin heavy loads....now to or three people a 20 would be in order.....actaully Stilletto does have a exchange program so can experiment in the real world..

 

[tmh]

Re: glastron sx195 5.0 merc

I have a 19' bowrider with a V8 and bought the Bay Pro 2 last season. Great prop. You may be a bot of a "tweener" on pitch. Previous advise of 18" if more load likely and for water sports, 20" if lighter loads or cruising. It's Stainless Steel you you'll have great performance. I'd say my min. plane speed went down maybe 2 mph from the 3 blade to the BP2 4-blade. I do have smart tabs though. We don't wakeboard so I can't comment on how the tabs effect it.

The BP2 picks the boat up very nicely - the stern and bow. I do get some chine walking at top speed, but not wild.

 

[propmann]

Re: glastron sx195 5.0 merc

We put a ton of 4 blade stainless Powertech props on that type of boat. I would put a 17 pitch 4 blade on it if you are wakeboarding alot with 4 or more people in the boat. A 19 if you are doing watersports with 3 or less people in boat. Powertech makes some if the best stainless props out there. If you would like to learn more about them leave me a message.

 

[lucky7]

Re: glastron sx195 5.0 merc

saw this posted up on craigslist near me, the guy said its a few years old but in fine shape, 100 bucks, has anyone used this pitch 21" stainless mitchigan 3 blade on my combo of a 19.5' glastron with the 220 hp 5.0?
i am thinking it might be fun for going fast,{60mph?} but maybe my motor hasnt got the ooomph to spin it? i can bounce the rpms off 5000 with just me in the boat, pulls 4300 when loaded to capacity with the stock 21" alum.

 

[JJJ]

Re: glastron sx195 5.0 merc

I am going to guess that your rpms drop so much loaded because you have much more hull in the water. Your 21P prop just doesn't have it to lift the boat.

I have a 20' Cobalt with the 4.3 in it and my rpms vary about 100-150 between fully loaded (9 people and coolers) vs. just me. The stock 13.75 X 21P prop didn't do it, so I am running a Solas 15.3 X 19P alum. prop. - the difference is amazing.

I too wish to go to SS but haven't gotten any input on what to try. I had a powertech 4 blade and it didn't have the lift either - felt like it might have lifted the stern but pushed the bow down

 

[Action]

Re: glastron sx195 5.0 merc

saw this posted up on craigslist near me, the guy said its a few years old but in fine shape, 100 bucks, has anyone used this pitch 21" stainless mitchigan 3 blade on my combo of a 19.5' glastron with the 220 hp 5.0?
i am thinking it might be fun for going fast,{60mph?} but maybe my motor hasnt got the ooomph to spin it? i can bounce the rpms off 5000 with just me in the boat, pulls 4300 when loaded to capacity with the stock 21" alum.

I have got a GXL 185, very similar performance to your boat but I would say mine can hold the plane at a bit lower speed. Have you thought about A merc Laser II prop? Maybe a 13 7/8 x 21p? I guess you have to decide what you want. You go to a 4 blade 20pitch perhaps, you'll probably get a better hole shot but probably lose on the top end. I think for what you have the performance sounds spot on....I have a buddy with an ssv 195 glastron with a 4.3L LX in it....he can probably hold a plane at about 17 mph, but then again he doesn't have a heavier 5.0L V8 in the back...

 

[lucky7]

Re: glastron sx195 5.0 merc

thanks for the input, i think im going to try a 4 blade alum maybe 19 pitch. not sure which one. anyone have an amita?

 

[JJJ]

Re: glastron sx195 5.0 merc

I looked at the Amita (since I run the 3 blade Amita), but opted to try the Volvo QL 4 blade 19P. I haven't put it on yet, so won't know how it compares to the big Amita 3 blade until July 11-12th.

 

[Tail_Gunner]

Re: glastron sx195 5.0 merc

http://boatpropellers.iboats.com/Me.../1143/?**********=635107800&*******=373183150