Question for GN7

[WESTERNAERO]

Why are struts squared off in the back? I understand for the rudder but every lower drive unit you see is tapered on the back side leading to the prop. What's different on a V-drive prop that the strut is squared off on the trailing edge.17997
Looking down on a strut, 2 examples of what I asking about.

[WESTERNAERO]

Maybe these 2 pics are a better example.1799817999

[wannabe]

you want the most meat where the greatest forces are. (the back of the strut.) And the more the power, the more the forces are at that back. And trust me, you want meat there! Also, making an angle can create sharp edges where a crack can begin.
With that being said, I won't let one of my boats go in the water with a squared off back of the strut. But I won't shape it like the front. Just a little to help the water pattern recover before the propeller. ;)

[WESTERNAERO]

Thanks, I understand the fracture critical deal, yes this makes sense. The CAD drawings are crude, they were just for a visual to understand my question. But I was thinking of some taper, maybe upper and lower would have a square or full radius and from there start the taper.
What are people using for material? I was thinking 15-5PH or 17-4PH.

[WESTERNAERO]

Hey Wannabe, is this Buzz or Paul or both? My cousin bought a guitar from one of you a few months back for his son. It was black with a triangle shaped body( I know nothing about guitars , forgive me me). His kid loves it, thanks. He said you gave him a smoken deal.

[78Southwind]

Maybe these 2 pics are a better example.17998

Westernaero....did you make that blast plate or did you have someone do the work for you? I am trying to find out what a reasonable price would be to install and make a bigger blast plate for the Spectra. The Spectra just has a fill plate where the old strut was (acting like a small blast plate).

https://lh5.googleusercontent.com/-aB1HXE1Z--o/Ui9x0O-ZbgI/AAAAAAAABuc/QHZNtKuIQKU/s640/BlaastPlate1.JPG

[WESTERNAERO]

Westernaero....did you make that blast plate or did you have someone do the work for you? I am trying to find out what a reasonable price would be to install and make a bigger blast plate for the Spectra. The Spectra just has a fill plate where the old strut was (acting like a small blast plate).

https://lh5.googleusercontent.com/-aB1HXE1Z--o/Ui9x0O-ZbgI/AAAAAAAABuc/QHZNtKuIQKU/s640/BlaastPlate1.JPG

Mr. Southwind, the pics I put up were google search pics and are not mine. However, you may be in luck. I will be making my self a blast plate for my Dimarco cruiser this winter when I re-rig it. It will be a quality piece and if you're willing to split the cost of the material with me I can easily make 2. I will not install it for you, but it shouldn't be tough if you have some mechanical ability and take your time. I love to help people it's just over the years I find myself with less and less time to do labor, so I have started to encourage everyone to do it themselves. I'm also going to be machining a bunch of parts for this build, so if you need something let me know. I've been looking at all your dimensions and we are real close. So for me to make 2 pieces of something on my CNC's is just a push of the button and no sweat if I can help you out. Feel free to call me, 818-970-1872, Kevin

[78Southwind]

Mr. Southwind, the pics I put up were google search pics and are not mine. However, you may be in luck. I will be making my self a blast plate for my Dimarco cruiser this winter when I re-rig it. It will be a quality piece and if you're willing to split the cost of the material with me I can easily make 2. I will not install it for you, but it shouldn't be tough if you have some mechanical ability and take your time. I love to help people it's just over the years I find myself with less and less time to do labor, so I have started to encourage everyone to do it themselves. I'm also going to be machining a bunch of parts for this build, so if you need something let me know. I've been looking at all your dimensions and we are real close. So for me to make 2 pieces of something on my CNC's is just a push of the button and no sweat if I can help you out. Feel free to call me, 818-970-1872, Kevin

Will do...Thanks Kevin

[WESTERNAERO]

Yep no problem, let me know what you need. And Menace marine is right down the street from my shop. So maybe you could hit them up to do install if you don't feel comfortable. Teague is also around the corner, if you need parts. Talk to Eric, he's a good dude and can answer a lot of questions you might have.

[gn7]

Sorry it took so long for me to answer this. I don't venture to the v drive forum much because it tends to be dead here.
Unforgiven is part right, part wrong. Sorry Ed. :action-smiley-069:

He is 100% dead on about the cracking. If a strut is going to crack or fail, it will start at the front of the strut where it is tapered to a sharp edge. I try to minimize that as much as possible, and as short a taper as possible, but its still pretty damn thin there.

But there is no forward thrust at all in the strut, and 99% of the forces it sees is upward and pretty even across the length of strut barrel. A little bit more towards the rear due to the prop being on that end, but its pretty even across the strut barrel. The wear of the bushing shows the forces, and they are almost entirely at the upper part of the bushing because the prop is trying to lift the ass end of the boat. On a hydro its entirely on the top side and virtually none anywhere else.
As to why the outdrives are tapered on the back side, and the V drives aren't, its kind of a physics thing, and a damn good thing it works out like this, or outdrives wouldn't work worth a shit.
Look at the bulk of the outdrive above the prop center line. Now compare that to the bulk of the strut above the centerline. Now look at the bulk under the prop centerline of both. Which has the most bulk in front of the prop in each case. The v drive nearly nothing above compared to the outdrive, and zero under the centerline.
The below centerline is where 90% of the work is being done on both cases. Look at a hydro. The prop is half out of the water. Same with a Ilmor, and Merc Nighthawk surface drives and in the right conditions on the right hull, a #6 and 8 Merc, and some Imcos. AND THEY HAUL ASS! At any given point in the prop rotation, the downward ear, to the mid rotation point, is doing much more work that the upward ear(s). Its the downward push that lifts the ass end, on any boat, specially a hydro. If the upward ear did the same work, they would cancel each other, and hydros wouldn't lift, and surface drives would be stuck in the water.
Another reason the bulk above the prop on a V drive means so little and has a little more effect on the outdrives is the number of blades. On a v drive the blade at the top is doing near nothing except thowing water off the perimeter of the blade into the bottom of the boat. It lends very little to the forward motion of the boat. Again, look at hydros. NO blade in the water ot the top at all. Look at the speeds of hydros and surface drives, they don't miss that balde out of the water one bit.
If the upper blade did much, the outdrive would suffer much more than the skinny ass liitle blade the strut has.
So the fact is, the tapered on both ends skeg of the outdrive is effecting the prop more than the blunt back side of the strut on a v drive, because its under the prop centerline where the prop is doing the majority of it forward thrust.
Make sense?

[WESTERNAERO]

Sorry it took so long for me to answer this. I don't venture to the v drive forum much because it tends to be dead here.
Unforgiven is part right, part wrong. Sorry Ed. :action-smiley-069:

He is 100% dead on about the cracking. If a strut is going to crack or fail, it will start at the front of the strut where it is tapered to a sharp edge. I try to minimize that as much as possible, and as short a taper as possible, but its still pretty damn thin there.

But there is no forward thrust at all in the strut, and 99% of the forces it sees is upward and pretty even across the length of strut barrel. A little bit more towards the rear due to the prop being on that end, but its pretty even across the strut barrel. The wear of the bushing shows the forces, and they are almost entirely at the upper part of the bushing because the prop is trying to lift the ass end of the boat. On a hydro its entirely on the top side and virtually none anywhere else.
As to why the outdrives are tapered on the back side, and the V drives aren't, its kind of a physics thing, and a damn good thing it works out like this, or outdrives wouldn't work worth a shit.
Look at the bulk of the outdrive above the prop center line. Now compare that to the bulk of the strut above the centerline. Now look at the bulk under the prop centerline of both. Which has the most bulk in front of the prop in each case. The v drive nearly nothing above compared to the outdrive, and zero under the centerline.
The below centerline is where 90% of the work is being done on both cases. Look at a hydro. The prop is half out of the water. Same with a Ilmor, and Merc Nighthawk surface drives and in the right conditions on the right hull, a #6 and 8 Merc, and some Imcos. AND THEY HAUL ASS! At any given point in the prop rotation, the downward ear, to the mid rotation point, is doing much more work that the upward ear(s). Its the downward push that lifts the ass end, on any boat, specially a hydro. If the upward ear did the same work, they would cancel each other, and hydros wouldn't lift, and surface drives would be stuck in the water.
Another reason the bulk above the prop on a V drive means so little and has a little more effect on the outdrives is the number of blades. On a v drive the blade at the top is doing near nothing except thowing water off the perimeter of the blade into the bottom of the boat. It lends very little to the forward motion of the boat. Again, look at hydros. NO blade in the water ot the top at all. Look at the speeds of hydros and surface drives, they don't miss that balde out of the water one bit.
If the upper blade did much, the outdrive would suffer much more than the skinny ass liitle blade the strut has.
So the fact is, the tapered on both ends skeg of the outdrive is effecting the prop more than the blunt back side of the strut on a v drive, because its under the prop centerline where the prop is doing the majority of it forward thrust.
Make sense?
Yes this makes sense, thank you very much.

[WESTERNAERO]

GN7, so with 90% of the work being on the bottom of the prop, Does it really make a difference if the mounting flange on the strut is flush with the bottom of the boat. See strut pic, this is what I have now.18068

[gn7]

GN7, so with 90% of the work being on the bottom of the prop, Does it really make a difference if the mounting flange on the strut is flush with the bottom of the boat. See strut pic, this is what I have now.18068

As far as the prop is concerned, it makes no difference. As far as overall hull drag, like anything else under the boat like fins, rudder, water pickups, the entire strut, and even the prop shaft itself, it makes a difference. Putting your index finger in the water at 100mph does not effect the prop, but it effects the speed of the boat.

[WESTERNAERO]

I'm planning on building a new strut, so really I'm just trying to get ideas on which way to go. The hull thickness on the boat is only about 3/4" so I'm thinking a drop thru might be best. If I recess the bottom and do a bolt on like I have, the floor will be too thin I'm thinking. Then I will have to do glass work inside to build it up. The pic below is the main reason for doing a new strut, the whole thing should have been about a 1/2" higher to begin with. Plus I'd like to move up to 1-1/8 dia shaft.
18093

[WESTERNAERO]

So what do you think GN7? Drop thru, bolt on without the recess or bolt on with recess and build up the inside. I not going racing and I'm not trying to rotate the world, I'm just wondering which would be the best option. What you think, Thanks.

[gn7]

Hydrodynamic drag squares with speed. If the thing doesn't hit 80+, and you never expect it to, then I am not sure there is much benefit. If you are considering a 1 1/8 shaft, sounds like some HP is anticipated. Drop thrus are not only more streamlined, but done correctly, its stronger.

[WESTERNAERO]

Funny you say that, The last time I had it out I actually checked the speed on a GPS and we were doing 82 mph @ 4900 RPM with a lot of boat it the water. And that was with 0 boost actually it was -1 on the gauge. So I am concerned about safety as i start swapping pulleys and making more power. Hence the strut and shaft swap this winter along with moving it up a little to stop the shaft from rubbing. So a drop thru should be the plan you think?

[gn7]

Funny you say that, The last time I had it out I actually checked the speed on a GPS and we were doing 82 mph @ 4900 RPM with a lot of boat it the water. And that was with 0 boost actually it was -1 on the gauge. So I am concerned about safety as i start swapping pulleys and making more power. Hence the strut and shaft swap this winter along with moving it up a little to stop the shaft from rubbing. So a drop thru should be the plan you think?

don't get me wrong, the bolt on surface steel strut is more than strong enough for a lake/river boat. I was only saying that the surface mount doesn't make much diff at speeds under 80 or so as far a drag. Your setup will handle more power than you are giving it. There have been GNs pushing more then 1000HP with surface bolted struts and 1 shafts(Aquamet22 or K Monel), they may have given up a little in top speed due to drag, but OK so far as strength.

The biggest issue I have with you current setup is the rusted chrome at the weld. Campbell Carl had a similar strut and the weld failed due to the rust. Its hard to tell exactly how much the strut is effected unless you remove it and strip off the chrome. But the strut itself is pretty stout, like somebody planned to put so power to it.

[WESTERNAERO]

don't get me wrong, the bolt on surface steel strut is more than strong enough for a lake/river boat. I was only saying that the surface mount doesn't make much diff at speeds under 80 or so as far a drag. Your setup will handle more power than you are giving it. There have been GNs pushing more then 1000HP with surface bolted struts and 1 shafts(Aquamet22 or K Monel), they may have given up a little in top speed due to drag, but OK so far as strength.

The biggest issue I have with you current setup is the rusted chrome at the weld. Campbell Carl had a similar strut and the weld failed due to the rust. Its hard to tell exactly how much the strut is effected unless you remove it and strip off the chrome. But the strut itself is pretty stout, like somebody planned to put so power to it.

Thanks for your time and opinions GN, I do appreciate it. Hope I'm not bothering you with this on this site, I know you spend most of your time on PB. I would like to get the V-drive area here up to speed here though.
This boat was original rigged by Dimarco with a blown BBC. It probably explains why this boat is setup originally with the strut angle and position very close to what other guys are changing to with their Howards and Spectras. I'm with you on the chrome, it makes me nervous not knowing whats under there. Just one more reason I'm planning on changing it.

[gn7]

That thing looks like it was built to take some power. Didn't mean to make too much of the strut, just a heads up that the chrome can hide some stuff. I seriously doubt it would ever fail catastrophically. Just keep an eye out for cracks that night appear in the weld area until get around to replacing it.
Odd that your shaft hole is off like that. Not sure the strut was suppose to have a shorter web, as much as I think somebody oopsied a little when they done cut it. They are usually with the strut in place, and a shaft run thru the strut with a hole saw on the end. If they don't watch what they are doing, the hole saw can walk down the hull a little before it bites in and starts cutting.

As for PB, that place is a spin off of the original HB, and the V drive guys were the first ones to make the move when HB was flaming out. The V drive forums there still get the majority of the posts. Each site kind of takes a direction from the start and heads in a general direction. Not sure why, but the V drive forums there are kind of petering out. Jet and dyno forums are still holding their own pretty well. But the V drive forum has taken a dip lately.
Still WAY more boating content at PB and here than there is at RDP. That place is 100% lounge, and by invitation only. No party crashers allowed unless you sit down and shut up. They will let you know when its your turn to speak, and what to say, and to who. Place is foocked up.

[wannabe]

Yeah, this is Buzzz. Paul goes by FC Pilot. you will see him around.
And yeah, when I have something that I don't need, I give them away for a pretty good deal. I just figure that I would have loved to get a deal like that when I was starting out, so why try to get rich off of something that I am not using. I did a boat less motor for a case of MtDew, parts for cheap and even a guitar or two. I am glad that the kid digs the guitar. That instrument kept me out of trouble and out of spending cash for many years. :)
Now, Bob, I don't mean to argue, but I do have one question; Do you really think the strut gets almost equal force front to back? I see prop shafts break all the time. Even one on a TAF today. They always break right at the back of the strut. NEver seen one at the front.

[gn7]

the wear patterns in the bushing are reasonably even front to back, with slightly more wear towards the back at the top. Most of the wear is between 11:00 and 2:00. We, as well as most people run 2 bushings. It the rear was the only one that wore, we wouldn't bother with the front piece.

Shafts break where they do because of the key slot. They always break right at the back of the prop, and the end of the key slot. The key slot creates a stress riser, any slot milled into a shaft. Thank goodness, because if it didn't, then the shaft would and could break anywhere along its length, and you can imagine the disaster that could create.
the LIFT of the prop on the shaft isn't what breaks them, its the torsional twist, not different than when a crank snout breaks. Which BTW, also ALWAYS break at the end of the key slot, and very seldom at the front crank throw arm, which is the next most likely spot.

Input and output shafts on the V drive, same thing, always at the end of the key slot. Occasionally END of the gear splines.

Broken a couple output shafts on desert M/Cs as well. Splines and key slot are the bane of all power shafts.

Every crank snout I have ever seen snap, broke behind the t gear at the end of the key slot. All the power is transmitted thru the damper, and there is no mechanical connection between the damper and T gear, yet never once seen a snout snap between the 2 in the middle of the key slot. The front crank throw arm sees every HP being passed thru the crank, as opposed to the rear crank arm the see near nothing. (opposite a car engine). The front arm is the second most likely place to break the crank. But never in the middle of the snout.
Just like the prop shaft breaking behind the strut, this is not caused by up forces, or some directional thrust, its 100% due to torsional twist.

18272

[WESTERNAERO]

I've started drawning up the new strut. What do you think? Have anybody ever used the engine mount as the gusset/brace before, is this wise to do? Opinions are welcome, it's much easier to change the CAD drawing now. Thanks.

183711837218373

[gn7]

I've started drawning up the new strut. What do you think? Have anybody ever used the engine mount as the gusset/brace before, is this wise to do? Opinions are welcome, it's much easier to change the CAD drawing now. Thanks.

183711837218373

There are guy that do it and swear by it. Greer Rush swore about it. TGN 24 boat had it for one race, and at the next it was gone.
I'm kind of neutral about myself.

[78Southwind]

Very Nice...

[WESTERNAERO]

I wonder if maybe it would be TOO rigid, or maybe being tied together like that you might get some really bad harmonics every where. Hmmmm?

[gn7]

It can never be too rigid, and I am not all that sure that vibrations and harmonics is such concern. The stringers deal with it. But I know the engine moves a lot more tan many people think, and the question becomes, is the engine holding the strut, or is the strut bracing the engine?

[WESTERNAERO]

With the engine tied to the stringer rails and the strut brace tied to the stringer rails, would the movement of the engine be transferred to the strut the same as if they were rigged like the CAD drawings?

[gn7]

With the engine tied to the stringer rails and the strut brace tied to the stringer rails, would the movement of the engine be transferred to the strut the same as if they were rigged like the CAD drawings?

I can only say that I have seen drag and some river flats with the strut tied to the block, but usually the stringers. Not sure I have ever seen a circle flat with the strut tied to anything. But I KNOW I the few GNs that tried it, were only that way for a couple races. Every V bottom I know of has a either a large strut box like mine(its huge) bolted and glasses into the bottom, or just bolted, or just alum angles bolted to the bottom and the strut.
Is it because the bottom moves around more than a flat? Or because they deal with rougher water? I don't know. I only know that I haven't seen a hard running V bottom with the strut tied to the stringers or engine.
And I know my engine moves around more than I would have thought. If I am not mistaken, the SS80 and a couple others have struts tying the engine to the stringers, along with the motor plates. I have considered it, or using 1/2 plate and blocks on both sides of the plate.

[Mitch]

The bottom needs to move around tying it all together will promote stringer fatigue or lifting of the stringers . Constant pounding on the bottom will try to push the motor plate up taking everything with it . Use a drop thru with a block or a recessed bolt on .

[gn7]

The bottom needs to move around tying it all together will promote stringer fatigue or lifting of the stringers . Constant pounding on the bottom will try to push the motor plate up taking everything with it . Use a drop thru with a block or a recessed bolt on .

I have to agree. I think its more a twisting thing than anything else. You might me able to built the hull strong enough front to back to eliminate most of the bending forces the hull sees, but its near impossible to eliminate the hull twisting. Its why v drive and engine bracing struts tend to have heims on the ends. They can arrest forward and rearward movements without inhibiting the twisting. No matter how stiff you make the stringers, the hull will still twist. About the only thing that can control the hull twist is to lay the sides up taller and heavier, and even the deck.

I know a lot of people say that tying the strut into the stringers is no different than tying the v drive into them, or even the motor plates for that matter, but I only know it has never worked well for a GN. And that Di Marco cruiser is closer to a GN than its a drag flat.
Not all that certain if the motor in my boat is what's moving, or the stringers twisting, but there is definite movement between the motor plates and the stringers. It would surprise me a bit if it was the stringers twisting in spite of the motor plates tying the stringers together, and the twisting wins. Just another reason the engine bracing I usually see use heims on the ends.

[Mitch]

Gn7 Its amazing how much the bottom moves in the V drive area my V drive had a solid 1/8 inch of clearence from the plate to the floor ,after one season the groove in the bottom from hitting the plate was very noticable.The force on my V drive plate is 10 degrees up and forward on one side and down on the other, now tie the V drive to the floor dead center to stiffen that area up just for conversation ,,that energy would have to be displaced somewhere. Funny you mentioned V drives a friend was glassing a strut bushing in his shaft log the other day and my first thought was this . Your taking something that floated thru a hole allowing it to seek its own path seperate from the bottom now its attatched and every time the bottom moves it goes with it ?If nothing else it seems like it would play hard on the V drive output shaft bearing .

[WESTERNAERO]

Thanks guys for continuing this discussion about this, I'm trying to understand why or why not to brace a drop thru. Below are a couple pics I got from some recent GN boat builds that are braced. Hope these guys don't mind me using their pics as examples.
My opinion on the bracing is that, it is there to limit any lateral movement of the strut when turning. I don't feel there should ever be any twisting or torsional forces going on with the strut as the prop shaft is supposed spin freely. Not quite sure I understand how there would be vertical movement on the strut that would put enough force to separate the stringers from the hull, although there is some I'm sure, but not enough to transfer to the stringers through a brace and start any damage. If this were the case with vertical forces a drop thru would be much, much weaker than a bolt on, correct? I do agree with that the motor plate may not a good brace as the torque of the engine could be transferred to the strut and cause some lateral motion. So, continue on, tell me I'm an idiot it's okay, just explain why. Thanks.
184411844218443

[gn7]

Gn7 Its amazing how much the bottom moves in the V drive area my V drive had a solid 1/8 inch of clearence from the plate to the floor ,after one season the groove in the bottom from hitting the plate was very noticable.The force on my V drive plate is 10 degrees up and forward on one side and down on the other, now tie the V drive to the floor dead center to stiffen that area up just for conversation ,,that energy would have to be displaced somewhere. Funny you mentioned V drives a friend was glassing a strut bushing in his shaft log the other day and my first thought was this . Your taking something that floated thru a hole allowing it to seek its own path seperate from the bottom now its attatched and every time the bottom moves it goes with it ?If nothing else it seems like it would play hard on the V drive output shaft bearing .
Your buddy is going to end up tearing the shaft log out of the boat, GUARANTEED!

Thanks guys for continuing this discussion about this, I'm trying to understand why or why not to brace a drop thru. Below are a couple pics I got from some recent GN boat builds that are braced. Hope these guys don't mind me using their pics as examples.
My opinion on the bracing is that, it is there to limit any lateral movement of the strut when turning. I don't feel there should ever be any twisting or torsional forces going on with the strut as the prop shaft is supposed spin freely. Not quite sure I understand how there would be vertical movement on the strut that would put enough force to separate the stringers from the hull, although there is some I'm sure, but not enough to transfer to the stringers through a brace and start any damage. If this were the case with vertical forces a drop thru would be much, much weaker than a bolt on, correct? I do agree with that the motor plate may not a good brace as the torque of the engine could be transferred to the strut and cause some lateral motion. So, continue on, tell me I'm an idiot it's okay, just explain why. Thanks.
184411844218443

Never said there were torsional twisting forces in the strut. The stringers and hull twist. When they do, the bracing, if tied to the stringers, can tear up the bottom near the strut, of loosen the stringers near the bracing.

These two boats, Andrews and Locks have ZERO time on them to speak of. Locks is ZERO, and Andrews has the enduro under its belt. Pretty smooth water relatively speaking. We'll see how it works out for them.
Not telling you not to tie the strut to the engine, telling you I know of no GN currently running that has the strut tied to the engine or stringers.
I have to ask again, when tying the strut to the engine, are you bracing the engine, or the strut?
The other thing I always have to ask when I see this setup is, which came first, the strut placement, or the engine placement. Its just shear lucky that the motor plate and the strut end up like that? I know I can't tie my strut to the motor plate if I wanted to. Would I move either so I could? FUCK NO! So I guess you have to be pretty damn sure where you want that engine when you do this, OR you just stick the engine where it all works out so you can.

[WESTERNAERO]

Your buddy is going to end up tearing the shaft log out of the boat, GUARANTEED!


Never said there were torsional twisting forces in the strut. The stringers and hull twist. When they do, the bracing, if tied to the stringers, can tear up the bottom near the strut, of loosen the stringers near the bracing.

These two boats, Andrews and Locks have ZERO time on them to speak of. Locks is ZERO, and Andrews has the enduro under its belt. Pretty smooth water relatively speaking. We'll see how it works out for them.
Not telling you not to tie the strut to the engine, telling you I know of no GN currently running that has the strut tied to the engine or stringers.
I have to ask again, when tying the strut to the engine, are you bracing the engine, or the strut?
The other thing I always have to ask when I see this setup is, which came first, the strut placement, or the engine placement. Its just shear lucky that the motor plate and the strut end up like that? I know I can't tie my strut to the motor plate if I wanted to. Would I move either so I could? FUCK NO! So I guess you have to be pretty damn sure where you want that engine when you do this, OR you just stick the engine where it all works out so you can.

Really the only reason I thought of tying the engine and strut together were because they are all ready in that location and it would have eliminated the extra brace. And really the only reason I'm even considering using a strut brace is because the inside of my boat hasn't been glassed thicker in the strut area. It's only about .700 thick. Here's a pic of what it would be comparing the 2 types of mounting. I just fear pulling the bolts though the hull in a drop thru. 18453

[gn7]

I understand what you are saying. Thankfully I don't have that concern. My bottom is over 1 1/4 thick between the stringers and the strut block is about 12 X 12 single piece of machined billet, bedded, bolted, and glassed in.
I really can't give you an answer on what you should do. Will Andrews and Locks deal workout, I have no idea. I guess tell. If you are beating the thing like a rented mule it guess it can work with no problems.
I can only tell you that I can show you a number of places in my boat that prove the boat is twisting more than I would have ever imagined. And there is nothing light about my boat.

I see your reasoning, I just can't give you answer what you should do, other than ask if you think you really need to have a drop thru. Speed?

[WESTERNAERO]

I understand what you are saying. Thankfully I don't have that concern. My bottom is over 1 1/4 thick between the stringers and the strut block is about 12 X 12 single piece of machined billet, bedded, bolted, and glassed in.
I really can't give you an answer on what you should do. Will Andrews and Locks deal workout, I have no idea. I guess tell. If you are beating the thing like a rented mule it guess it can work with no problems.
I can only tell you that I can show you a number of places in my boat that prove the boat is twisting more than I would have ever imagined. And there is nothing light about my boat.

I see your reasoning, I just can't give you answer what you should do, other than ask if you think you really need to have a drop thru. Speed?

I just figured if I am going to re-do everything this winter I'm going to make it as strong as possible, I've been known to break shit with the vertical peddle before. The boat actually drives very nice. This whole re-rig thing started because I don't have a down peddle and this boat has the potential to go faster than I've ever had it, but it makes me nervous not having that down peddle so I don't push it. Like I said earlier, I was doing 82 and didn't even realize it because I wasn't even giving it full throttle. So now it's like, what's this things weak parts? and lets fix them now while it all apart. I'm thinking now I should probably get in there and start building up the glass in the bottom. Which ever way I go with the strut I think it safe to say that the bottom should be thicker regardless. Thanks for your time GN, and Mitch.

[steveo143]

On my 19' Schiada, I put a drop thru strut in and made a 2" thick block that sits on top of the clamshell at the rear and is bolted to the motor plate. Seems to work great for me.

[WESTERNAERO]

On my 19' Schiada, I put a drop thru strut in and made a 2" thick block that sits on top of the clamshell at the rear and is bolted to the motor plate. Seems to work great for me.
Can you put up a picture of that?

[SFV2RVR]

Mine is also tied in the the stringers.
23351

[rivergames]

I would tie them to the stringers. I installed mine just like the one SFV2RVR just posted

[Wheeler]

Mine is also tied in the the stringers.
23351


Almost too pretty to cover up with an engine! :thumb::thumb:

[2manymustangs]

Great thread, I like these discussions!!!!!!!!!!!!!

SOOOOOOO much to learn...

Thank you GN7 & all...

[2manymustangs]

bump..........

a great discussion, a stroll down memory lane.......... :grad:

[Toolman]

Great thread guys!!! Westernareo, if ur worried about ur floor thickness, since u said u have cad and cnc access, design a strut that reaches out towards the stringers another 3'' or so per side and add another row of bolts. Then fab ur own drop thru that will match it sandwiching more of the hull. Anyway, nice thread guys!

[Mrs.K034]

bump..........

a great discussion, a stroll down memory lane.......... :grad:

Yes, great discussions. [emoji22] and miss GN7. Wish I could have just a slice of his knowledge!


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[The Doctor]

Yes, great discussions. [emoji22] and miss GN7. Wish I could have just a slice of his knowledge!


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I'm afraid we'll have to earn it as he did. Bob was something special and a very good friend.

[Mrs.K034]

I'm afraid we'll have to earn it as he did. Bob was something special and a very good friend.

Agreed.


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[rschap1]

x2
Will be missed