If I may Racey, make that an absoulte must with all HP flattys or hydros. #197 hasn't used them forever, just larger than normal angle mount plates w/no sandwiching. I think most high HP V-bottoms set up correctly and not used offshore don't need the extra bracing. Again, if everything is finessed fit correctly. Just my 197 cents worth of input.The bracing is an absolute must, period, end of discussion, i don't care what anyone else has to say about it, Having the V-drive braced back to the stringers will prevent broken prop shafts, un-necessary bearing wear, and if that isn't enough reason how about loss of power.
The absolute most important part of rigging a v-drive boat is strut to v-drive alignment, they have to be within thousands of an inch to align properly, this is done with total finesse before any hole mounting the v-drive is drilled, if you have never had to rig one from scratch then you have no room to talk about how close that tolerance is, and how even 1/16 of an inch off will cause major issues, it's amazing how hard it becomes to turn the shaft when there is that tiny amount of bind applied to it. If they aren't within that fine line of alignment tolerance you will create unecessary bind which will load the shaft, wear out the bearings in the v-drive, create vibrations, cause shaft whip etc.
So now we come to the infamous V-drive braces, what you have to remember with a v-drive is that every single bit of thrust that pushes the boat forward is because the prop shaft is pushing the v-drive, and the v-drive is mounted to the boat. what ends up happening if you aren't running braces is the v-drive plate twists (the bottom of the plate tries to go toward the nose of the boat) EVERY PEICE OF METAL BENDS EVEN UNDER THE LIGHTEST OF FORCES. It's not uncommon to have thousands of pounds of thrust pushing against that v-drive which will twist that plate more than you'd imagine, the braces put almost a complete stop to this because twisting force is yeild strength not tensile strength (it's far far easier to twist and bend a peice of metal than it is to snap one by applying pulling forces to it, don't believe me, take a peice of wire and bend it, pretty easy, now try wraping it around the fingers of each hand and stretching it to the snapping point....). Aluminum plate braces (almost like the ones pictured above) work great as long you are using very tight holes through the plates and stringers, to where you need a hammer to tap fasteners through. Pre-loaded tie-rods work great too, you just have to be careful not to preload them very much, because they will pull the v-drive out of aligment in the other direction. the only problem with those plates in the picture above is that they are bent at the v-drive end, they should come in straight to a block as near the case possible.
That is the exact kind of brace i was thinking of! The bracket where it mounts the sandwich plate...is that cut and welded or bent in a press brake? And it looks like the sandwich has brackets on both sides where it mounts to the stringers?
Last night
.....red and 1/2 gal. clear coat....came out good, almost no dirt,got it to lay down plenty smooth (and i am not a painter in any manner shape or form) I go out an hour later and 2 moths had crashed and burned right in the middle of the deck.No biggie..i know how to sand and polish...probably cause i'm not a painter. lol
) but, at least in a 1200 hp K boat or most any sprint boat for that matter, where we have to deal with a very short stringer and not a lot of room for braces(not that I haven't done them) you will see VERY few of the fore/aft bracing done in these types of boats. It has been my experience that properly braced from the stringer the flex, over and above the the normal movement of the hull, is minimal. 
And now that i see the sandwich deal i like it too...less brackets. You build some impressive equipment...it's ok if i copy you?
I liked that sandwich thing so much i copied it..I couldn't find little pieces
like you used, all i could find was big piece of 1" stuff..it was really big but i bit the billet and cut it in half and made it work.
I don't have those big machines everybody else has to make big things smaller but i have this neat hand held carving tool with a 7 1/4" round blade with really sharp tips that makes these things that look like real metal flake. i just need to remember that they are really hot. I have a heavy duty 9"
surface/mill that makes it all smooth.
It's kinda messy doing it that way but at least it's noisy. I think my neighbors
like the noise, they are always telling me about it, and i know the guy next
door must really appreciate it, me getting up so early for work, I hear his
boss at p.d. doesn't put up with employees being late for work although
there probably isn't much he can really do, all the employees carry guns.
I didn't want to make it all shiny, that must be the easy way because
everybody seems to do it that way. I drove all over town looking for some
kind of black paint that didn't leave marks from my paint brush but all
i could find was this stuff in a spray can..It looked better right after i
painted it, but after it dried it got all wrinkly.
I need to get more bolts for it, i used up almost every one i have and i don't know it will be strong enough to keep all that wood from bending but if
it does i will use the the other half of that piece i found even it makes it
look all big...and if it does......I'll just name it..big things deserve names,
right?
I was thinking "Dave Sammons super billet gear box sandwich"
Oh..almost forgot pictures
:drunk
Well Mike, like they say there is more than one way to do about anything!I liked that sandwich thing so much i copied it..I couldn't find little pieces
like you used, all i could find was big piece of 1" stuff..it was really big but i bit the billet and cut it in half and made it work.
I don't have those big machines everybody else has to make big things smaller but i have this neat hand held carving tool with a 7 1/4" round blade with really sharp tips that makes these things that look like real metal flake. i just need to remember that they are really hot. I have a heavy duty 9"
surface/mill that makes it all smooth.
It's kinda messy doing it that way but at least it's noisy. I think my neighbors
like the noise, they are always telling me about it, and i know the guy next
door must really appreciate it, me getting up so early for work, I hear his
boss at p.d. doesn't put up with employees being late for work although
there probably isn't much he can really do, all the employees carry guns.
I didn't want to make it all shiny, that must be the easy way because
everybody seems to do it that way. I drove all over town looking for some
kind of black paint that didn't leave marks from my paint brush but all
i could find was this stuff in a spray can..It looked better right after i
painted it, but after it dried it got all wrinkly.
I need to get more bolts for it, i used up almost every one i have and i don't know it will be strong enough to keep all that wood from bending but if
it does i will use the the other half of that piece i found even it makes it
look all big...and if it does......I'll just name it..big things deserve names,
right?
I was thinking "Dave Sammons super billet gear box sandwich"
Oh..almost forgot pictures
:drunk
)
That should do it!
![Boat V-Drive 002 [Desktop Resolution].jpg](/forums/data/attachments/26/26865-4c8b73b1242af30c96a4fb797fda8e59.jpg)