Silent Thunder repair
#1
Thread Starter
Registered
Joined: Aug 2019
Posts: 55
Likes: 0
From: Rhode Island
I’m looking for any suggestions/advice on repairing our silent thunder platform on an 87 242ls. The rub rail no longer stays attached. I’m thinking of removing the platform at the end of this season.
Also, any information or thoughts on switching to. four blade stainless prop. Currently using a three blade 14x21. I’ve read that you normally drop down one pitch when switching to a four blade prop. The 242ls has the 454 with after market intake an d carb. I think the 19 would give me a little better low end performance out of the hole. I’d rather sacrifice a couple of mph top end. I know the 242ls is not a speed demon.
Many thanks for reading,
Tony S
Also, any information or thoughts on switching to. four blade stainless prop. Currently using a three blade 14x21. I’ve read that you normally drop down one pitch when switching to a four blade prop. The 242ls has the 454 with after market intake an d carb. I think the 19 would give me a little better low end performance out of the hole. I’d rather sacrifice a couple of mph top end. I know the 242ls is not a speed demon.
Many thanks for reading,
Tony S
#2
Registered

Joined: Apr 2014
Posts: 650
Likes: 123
From: North Florida
I think a 20 p Revolution would be perfect for your app. I will warn you that this is a somewhat pricey wheel, but the control and manners are super. Does your platform have rail rivets? Mine did. I drilled the rivets out and reattached the rub rail with #10 stainless oval head screws. Be prepared to find more work if you take things further apart. As far as your hull not being a speed demon, well that just depends on how you motivate it. There have been a few 242’s on this board that I would absolutely call speed demons. It all depends on how fast you want to spend. Good luck and great boat!
#5
Thread Starter
Registered
Joined: Aug 2019
Posts: 55
Likes: 0
From: Rhode Island
Thanks for the quick reply and suggestions and recommendations on propellers. My son in law and I may tackle a rebuild of the ST platform at the end of the season here in the northeast. Local marina will to a repair to get me through the season. Do you have any info on Solas, Turning Point or Bravo props. I know revolution props are pricey. What diameter should I look for with the 20 pitch..The drive is an Alpha 1. I’m new to this I/O world being a two stroke guy for many years. Always wanted the older Formulas the 242 ls. It is a great boat.
Thanks again for your help,
Tony S
Thanks again for your help,
Tony S
#6
Junk the pos platform. They can and do cause transom rot. I love you Formula but that was an absolute crap design. I know there are purists out there that say removing the platform takes away from the look. I say good luck with transom rebuilds. A tubular platform looks good on them especially if color coordinated.
Ditch the platform, your 242 will thank you.
I have nothing to add on propellers other than the say a 26P Bravo is not enough prop for a supercharged 242.
Ditch the platform, your 242 will thank you.
I have nothing to add on propellers other than the say a 26P Bravo is not enough prop for a supercharged 242.
#10
Registered
Joined: Sep 2009
Posts: 419
Likes: 14
From: Lake Winnipesaukee, NH
No one has asked what RPM you are getting from the 21. If it's getting where it should a 20 or 19 will be nice with the extra blade. But if it's held back bay the high 21" pitch you might need to just go all 19. I have a 19 Mirage Plus and it revs out well, I also have a 21 and it still gets 4550 or so.
An Alpha1 behind a 454 is a potential weak link. I have one in back of my 383. My engine probably doesn't make near the torque yours does and a 223 is lighter. To keep mine happy I put Amsoil Severe Gear in it and I put on a drive shower too. Cheap insurance.
In the meantime don't holeshot it too hard, just slide it onto plane.
Also, I believe TomZ has a bravo drive, he may have a taller gear set than we do. But if he's spinning a 26 with a 1.5 gear, that's cooking with gas!
An Alpha1 behind a 454 is a potential weak link. I have one in back of my 383. My engine probably doesn't make near the torque yours does and a 223 is lighter. To keep mine happy I put Amsoil Severe Gear in it and I put on a drive shower too. Cheap insurance.
In the meantime don't holeshot it too hard, just slide it onto plane.
Also, I believe TomZ has a bravo drive, he may have a taller gear set than we do. But if he's spinning a 26 with a 1.5 gear, that's cooking with gas!
Last edited by NHGuy; 07-09-2021 at 09:19 AM.



