user 1193
Member
- Joined
- Jan 7, 2004
- Messages
- 5
Hey guys,
I am normally a Dock guy but I have started spending time over here too. Here is a crazy boat that I have been working on for a while. I am attaching the text from my first post over there that explains what I am trying to do....
Hope you like it.
Tim
There are pictures at the bottom of the text. What I am trying to do here it to take most of the “tried and true” methods of boat operation and construction and toss them out the window. So major differences are suspension, surface drive ride pad, front steering, Full height stringers, among others.
Let go through some of the systems.
Front Suspension – The concept here is the same as on all other vehicles with suspensions. You cannot turn unless you have wheels in contact with the ground. So although water is a fluid and gives when a sponson hit it, the speeds that we race the water is still hard and pushes the bow up as well as displacing the water. Enter suspension, When the boat hits a wave in the turns the sponson will rise and fall following the contour of the wave. (or close to it) This should mean that the turn fin should need to be far shorter because the sponson is never that far from the top of the water. The boat should stay level and carve through the turn at high speed.
Rear Suspension – In a car you cannot accelerate unless you have your wheels on the ground. In a boat, you cannot accelerate without the prop at least partially in the water. So with a rear suspension you will keep the prop in the water as you pass over waves. The linkage here is maple. I will need to treat it before running. Eventually I would like to change it out to welded pipe, lexan or fiberlass plate. I also need to change the length of the front linkage. Right now it has the front of the ride pad lower than the back. I want to have a slight pitch down toward the back. Right now you can see the brass tube that is embedded in the ride pad. One last layer of glass needs to go over the assembly to wrap it up. I have included a picture of the first revision of the rear suspension. Much simpler but was not controlling the direction of the thrust well enough.
Surface drive ride pad – The prop is most efficient with ½ in the water and ½ out of the water. With all the waves we pass over while running at speed you have to imagine that the ½ and ½ condition is rather rare. It is more likely that the prop is unloading in the wave troughs and overloading at the wave crests. So if you were to follow the wave while maintaining the ½ and ½ you should be more efficient. The ride pad is a pad that has the driveshaft embedded in it. When the water hits the pad it lifts the rear of the boat and keeps the prop riding along the top of the wave profiles. The flex shaft going to the ride pad uses a thick wire spring over the Teflon liner. The spring then is connected to the wall in front of the engine and to a section of brass pipe that takes it to the prop. I have not put a rear skeg in yet but I know that I will need to. I may take the same aluminum profile I have above the fiber glass and add some to the bottom as the skegs.
Front steering – I figured it would be interesting to see how front steering changes the behavior of the boat. I use the turn fins on the inside of the sponsons as rudders. I haven’t adjusted the alignment yet. There seems to be a bit of adjustment to do on the camber/caster too. I like the spring adjustment on the shocks. You can very easily set the ride height.
Front Sponsons – The sponsons are just blocks of basswood that have been shaped. I am pretty sure that I will need more lift and will need to reduce the unsprung weight of the sponsons so I am thinking about changing them out for things that look like the skiis on a snowmobile. Heck I have taken enough ideas from a snowmobile already. I will probably need to have them be hollow fiberglass so they add additional flotation at low speeds. I was thinking that I would make them kinda spoon shaped. High up on the sponson it would be wide for more lifting during low speeds and then the profile of the sponson gets narrower to reduce drag as the boat hits higher speeds and rides dryer on the sponson.
Drag – I imagine the there will be a pretty good amount of drag on the front suspension until it gets up to speed. I am thinking about adding a little skid pad to the bottom of the lower A arm. This would help lift the boat until the suspension is out of the water.
Full height Stringers – The stringers are the body on this boat. There will be a front cowl to cover the exhaust and the carb intake but the stringers hold everything and act as the main portion of the exterior façade. You will notice that nose of this center hull is parted rather high. This is to accommodate any wave jumping. The center hull will keep it from porpoising.
Radio and fuel tank. I plan on putting these in the “tail” of this beast. The steering will have a thick pushrod on either side of the engine. I noticed while taking pictures that my steering link mount bar is crooked. Doh!
Weight – It is currently at 9 lbs. with the radio box, pipe and some skin material included.
Engine – I have the QD in there right now but I will probably start with the G260.
CG – The center of gravity is about 1.5” behind the rear of the sponsons.
Fabrication – The really frustrating part of all this has been the fact that I do not have the tools necessary to do the job correctly. You can only get things so accurate and decent looking with homebuilding tools. It is probably time to investigate the mill/lathe combos. Until then please excuse the rough look of the parts.
I hope to have this done in the next couple of weeks. I will need to find someone down south to send it to for testing. I wont have water here for months and months.
If it does not work I will turn the engine and make it a snowmobile.
Now I know some of you are asking Why? If you don't try different things how do you ever move forward?
Oh yeah one last thing. Boston is known for our lobsters. How does this one look?
View attachment 3968View attachment 3969View attachment 3970
I am normally a Dock guy but I have started spending time over here too. Here is a crazy boat that I have been working on for a while. I am attaching the text from my first post over there that explains what I am trying to do....
Hope you like it.
Tim
There are pictures at the bottom of the text. What I am trying to do here it to take most of the “tried and true” methods of boat operation and construction and toss them out the window. So major differences are suspension, surface drive ride pad, front steering, Full height stringers, among others.
Let go through some of the systems.
Front Suspension – The concept here is the same as on all other vehicles with suspensions. You cannot turn unless you have wheels in contact with the ground. So although water is a fluid and gives when a sponson hit it, the speeds that we race the water is still hard and pushes the bow up as well as displacing the water. Enter suspension, When the boat hits a wave in the turns the sponson will rise and fall following the contour of the wave. (or close to it) This should mean that the turn fin should need to be far shorter because the sponson is never that far from the top of the water. The boat should stay level and carve through the turn at high speed.
Rear Suspension – In a car you cannot accelerate unless you have your wheels on the ground. In a boat, you cannot accelerate without the prop at least partially in the water. So with a rear suspension you will keep the prop in the water as you pass over waves. The linkage here is maple. I will need to treat it before running. Eventually I would like to change it out to welded pipe, lexan or fiberlass plate. I also need to change the length of the front linkage. Right now it has the front of the ride pad lower than the back. I want to have a slight pitch down toward the back. Right now you can see the brass tube that is embedded in the ride pad. One last layer of glass needs to go over the assembly to wrap it up. I have included a picture of the first revision of the rear suspension. Much simpler but was not controlling the direction of the thrust well enough.
Surface drive ride pad – The prop is most efficient with ½ in the water and ½ out of the water. With all the waves we pass over while running at speed you have to imagine that the ½ and ½ condition is rather rare. It is more likely that the prop is unloading in the wave troughs and overloading at the wave crests. So if you were to follow the wave while maintaining the ½ and ½ you should be more efficient. The ride pad is a pad that has the driveshaft embedded in it. When the water hits the pad it lifts the rear of the boat and keeps the prop riding along the top of the wave profiles. The flex shaft going to the ride pad uses a thick wire spring over the Teflon liner. The spring then is connected to the wall in front of the engine and to a section of brass pipe that takes it to the prop. I have not put a rear skeg in yet but I know that I will need to. I may take the same aluminum profile I have above the fiber glass and add some to the bottom as the skegs.
Front steering – I figured it would be interesting to see how front steering changes the behavior of the boat. I use the turn fins on the inside of the sponsons as rudders. I haven’t adjusted the alignment yet. There seems to be a bit of adjustment to do on the camber/caster too. I like the spring adjustment on the shocks. You can very easily set the ride height.
Front Sponsons – The sponsons are just blocks of basswood that have been shaped. I am pretty sure that I will need more lift and will need to reduce the unsprung weight of the sponsons so I am thinking about changing them out for things that look like the skiis on a snowmobile. Heck I have taken enough ideas from a snowmobile already. I will probably need to have them be hollow fiberglass so they add additional flotation at low speeds. I was thinking that I would make them kinda spoon shaped. High up on the sponson it would be wide for more lifting during low speeds and then the profile of the sponson gets narrower to reduce drag as the boat hits higher speeds and rides dryer on the sponson.
Drag – I imagine the there will be a pretty good amount of drag on the front suspension until it gets up to speed. I am thinking about adding a little skid pad to the bottom of the lower A arm. This would help lift the boat until the suspension is out of the water.
Full height Stringers – The stringers are the body on this boat. There will be a front cowl to cover the exhaust and the carb intake but the stringers hold everything and act as the main portion of the exterior façade. You will notice that nose of this center hull is parted rather high. This is to accommodate any wave jumping. The center hull will keep it from porpoising.
Radio and fuel tank. I plan on putting these in the “tail” of this beast. The steering will have a thick pushrod on either side of the engine. I noticed while taking pictures that my steering link mount bar is crooked. Doh!
Weight – It is currently at 9 lbs. with the radio box, pipe and some skin material included.
Engine – I have the QD in there right now but I will probably start with the G260.
CG – The center of gravity is about 1.5” behind the rear of the sponsons.
Fabrication – The really frustrating part of all this has been the fact that I do not have the tools necessary to do the job correctly. You can only get things so accurate and decent looking with homebuilding tools. It is probably time to investigate the mill/lathe combos. Until then please excuse the rough look of the parts.
I hope to have this done in the next couple of weeks. I will need to find someone down south to send it to for testing. I wont have water here for months and months.
If it does not work I will turn the engine and make it a snowmobile.
Now I know some of you are asking Why? If you don't try different things how do you ever move forward?
Oh yeah one last thing. Boston is known for our lobsters. How does this one look?
View attachment 3968View attachment 3969View attachment 3970
