Inquisitor
BIG ENGINES: Silos today... Barn Door tomorrow!
- Joined
- Nov 1, 2005
- Posts
- 276
- Reaction score
- 11
- Location
- North Carolina Mountains
I’ve muddled on designing and building a boat for many years. Several years back I started the mental explorations of how to achieve my goals and started reading books, researching on forums like this and started the learning curves on the tools to help in the design process. I enjoy the daydreaming, designing and analysis. I also enjoy wood working and working with fiberglass and I enjoy sailing. Will the Roadster ever see the wind in her sails? I don’t know if I like fiberglass that much. However, for the cynics in the audience, I don’t expect to press the print button and get any satisfaction either.
I am not an artist. I am an aerospace engineer specializing in structural analysis using composite materials. Meaning, everything has been thought out till I’ve drilled down to China. HOWEVER, I am not a marine architect and I don’t have the practical sailing, designing and building experience that is the gold mine of this forum. There are almost no details that have a cosmetic only reason, so you might find the design rather bland compared to other artist renderings on this site. On deeper inspection you may find a beauty in its Teutonic detail, multi purpose utilization of components, its Transformer abilities and its absolute efficiency of using every cubic inch to the fullest. It is by no means a fully realized design and has some challenges to overcome. But that is part of the enjoyment for me.
Some of my ideas are rather radical and come directly from the aerospace industry. That doesn’t mean I’m certain they’ll work, but I’m willing to air them here so practical minds can throw darts… hopefully constructively!
So here we go…
My Criterion – in order of importance are…
1. Safety
2. Trailerable
3. Largest boat possible.
4. Able to single hand.
5. Speed
6. Comfort
My early inspirations were the designs by Woods. Strong, beautiful boats from an architect with a great reputation. How could I go wrong? Unfortunately, his Skua at 30’ and Sango at 25’, although trailerable, were just not something I’d want to live aboard. Any of his larger designs have to be planted in the water to stay.
Trailerable – Here are my thoughts on trailerable. I live in the United States. And I can imagine wanting some variety to my sailing grounds. I’d like to sail the Bahamas and Caribbean in the winter, Penobscot Bay in the summer, the Mexican Rivera in the winter and the Inside and Outside passages between Seattle and Denali in Alaska in the summer. Maybe throw in some Great Lakes time and even put in, in Jackson Lake in the Tetons. Anyway… you get the idea. From a safety standpoint, I also want to get it out of the water and head inland during the hurricane season. I don’t want any cordwood of mine on the shores of Louisiana! For those of you not familiar with these places… well they’re a long ways away from each other… and some not by water!
Well, trailerable gives me some definitive maximum dimensions. It must fit within 40’ x 8.5’ x 13.5’ when on the trailer. Apparently, there is some wiggle room on the width here, but in some locations here… there isn’t! So, for the moment, I’m sticking with 8.5’. Among many other reasons (for me) this pretty much rules out monohulls and trimarans.
Comfort - Although down on the list, here is what I mean for comfort. I want to be able to live on it… period. Not camping, not roughing it. A shower I can stand in and a bed I don’t have to crawl into are a must. I don’t want to duck much but I’m only 5’7” so that isn’t much of an issue anyway. I want to entertain guests… basically, I want to live 2, sleep 6 and entertain 20.
This requires a hard bridge deck! This drove me toward the Sango’s articulations. Unfortunately, they just simply won’t scale and still fit into the box given the 7’ head room requirements I want. I briefly entertained the scissor scheme, but again it takes up way too much volume for that articulation when the only time that volume is used is during the expanding. So, I decided on the sliding beam concept similar to the Skua.
Speed versus Single Handing versus… well SPEED
This one burned the midnight oil many times. I like speed. Although I want to race it, I want to live on it and that means single handing most of the time… or assuming, at least, that in the worst of conditions, it still must be single hand able. I also want to be able to use it for as long as I can stand up… 70’s, 80’s… Maybe I can still push buttons into my 90’s. I’ve daydreamed over the likes of Hydroptère, Orange, Playstation, BMW’s America’s cup and just about every architect who offers plans or techniques. Nothing had the exact combination I wanted. And my 401k plan isn’t what it used to be. So, here I am… rolling my own. If I get everything down on this thread, you should see a lot of different influences. In the end, I centered on two designs that are my driving force for realistic speed… The Z40 Roadster is based mainly on parameters gleaned from the Extreme 40 and the Gunboat 48. By aiming high, I hope to at least break 20 knots in ideal conditions.
Design
I am still relatively early in the design spiral and have only made several cycles. My analyses include simple closed-form solutions, mechanics of materials methods, LPT theory and Dave Gerr’s scantlings in spread sheets. Yes, I know, he clearly says his scantlings do not apply to catamarans. I am mainly using it for ball park sizing, weights and cost analyses at the moment and no more. However, if anyone is willing (and able) to quantify that disclaimer, I would greatly appreciate it. A single hull falls within his acceptable dimensions, so I’m assuming (for the moment) that his disclaimer is due to the high stress concentrations incurred by cross beams that his scantlings do not address.
So without further fan fare here is how it stands (at the moment)…
LOA = 40’
BOA = 23’ (Collapsed 8.5’)
Hull Beam = 4’
Maximum displacement = 13,000 lbs - I want to make sure it is possible to tow with the Dodge/Ford/GM 350/3500 class of pick-up trucks using a 5th wheel configuration. As you’ll see, the 5th wheel configuration will be required as I have to move the trailer wheels far back from the balance point for height reasons and thus too much weight would be on the hitch.
So far weight is a growing target. I am currently experimenting with resin infusion methods to try and get the fiber density up. At the 35% number Dave Gerr states the boat is just plainly not feasible. However, if I can get near the fiber percentage claimed by resin infusion, and with the following accounted for…
• All fiberglass
• All Epoxy
• Foam core
• Windows (probably UV protected Lexan)
• Teak or artificial teak decking (may have to go)
• Engines
• Batteries
• Water
• Fuel
…AND the optimistic resin infusion fiber density, I have a gross weight before people of about 8500 lbs.
TP Mast Design
If you’ve already seen the pictures, you’ve probably already noted the masts (Plural). To my knowledge, I’ve not seen this configuration before, but I’m sure if it’s out there, someone here on this forum has either designed it or knows about it. Please let me know. I’ve seen many free standing (Schionning) and some with cross pieces (Yves Parlier’s “Médiatis Région Aquitaine”) so I’m coining the phrase TP Mast. The configuration solves many problems.
Pros
1. No huge support structure to hold a center mast.
2. No huge support structure to hold free standing bi-plane masts
3. Triangulation (strongest form in nature or man-kind)
4. Wing masts have no supporting shrouds for lateral stability.
5. Masts can rotate 360 degrees as many times as necessary.
6. Main sails are furled AROUND the masts.
7. 150% Genoa are furled around dual forestays.
8. Redundant forestays and backstays for safety and strength
9. Masts are stepped on rigid posts above the deck.
10. Masts can be stepped using the booms and dual anchor lasses. (Usually something in the size range requires a crane)
11. Due to the lower center of wind pressure and tilt of masts, more sail can be carried than a conventional single mast.
12. Lower windage with less shrouds and weathervaning of mains when sails are lowered.
13. Masts can be lowered to clear bridges while motoring.
Cons
1. Interference of multiple sails decreases efficiency of sails
2. Wind speeds are lower at lower heights. Sails aren’t as tall as a conventional design.
Just to give perspective for item 10 above. At the full gross weights and each using 100% foresails… the 13,000 lbs Z40 Roadster can carry slightly more sail area than the 17,700 lb Gunboat 48. They will both start lifting the windward hull at the same wind pressure. In this configuration the Z40 Roadster can carry 1650 square feet of sail! Hopefully, this will overcome the inefficiencies described in the Cons.
Oh! Almost forgot the amenities…
• Two queen size births in the hulls.
• 108 sq ft for the Master stateroom with King size bed forward in the bridge deck. Most Admirals (that I’ve read about) clearly dislike the “living in a cave” feel associated with living down in a monohull or even worse in a claustrophobic catamaran. This Master stateroom has panoramic views of your favorite anchorage.
• 120 sq ft in the Galley
• No, interior sitting, dining area – a deficiency to some, but then I don’t plan on sailing in cold climates WHEN it’s really cold. My suth’n blood would freeze solid.
• 120 sq ft in outside sitting, dining area with seating for 10 and another 10 could easily “join” the conversation on top of the hulls.
• 34 sq ft main head with full size standing shower (30” x 30”).
• 36 sq ft Master head with shower (and maybe whirlpool bath) if weight can be balanced. The Admiral likes baths!
• Full walk in Master closet… guess who?
• 32 sq ft shop / office / dual bunk beds area.
• 3’ bridge deck to water clearance for reduced pounding
• 6.5 to 7’ headroom throughout
• The bridge deck roof lowers for “spirited” sailing for reduced windage, structural stiffness and looks. It can be raised while sailing, but the windward foresail cannot be fully extended (only about 100%). Hard windows fold into roof. “Think” modern hardtop convertibles (BMW 3 Series) NOT popup campers.
• Hardtop Bimini
o Can be slid forward atop roof for full sun into the seating area.
o Can be slid back and fastened to hand railing when the roof is lowered… have to see the pictures.
o Can be slid back and fastened to the traveler when the roof is up… again see the pictures.
• Dual cockpits in rear corners. Unrestricted sight lines (when top is down) to all points.
• All control lines will be below decks and lead aft to the cockpits for single handing.
• Steering, I’m thinking about an aircraft joy stick type arrangement. Requires less room than a wheel, and with more feel. Also will be able to have multiple places for “joy sticks” that are mechanically attached… both cockpits, one inside the Master stateroom… maybe others.
• Also, emergency tiller can easily be attached to the top of the rudder and still sail from the cockpits.
• Rudders are offset to the outside of the hulls for egress and for improved efficiency when heeling. They also flip up if struck.
• It also uses swing keels instead of dagger boards that also swing up if struck.
• Engines are electric (so far) and will be housed near the fore/aft centerline to
o facilitate turning on its center point
o protected props. Props should be fully above the bottom of the hulls.
o Permit backing and beaching the stern and allow dry walk off/on.
• Hard dingy is stowed forward under the bridge deck.
o No ugly dingy hanging off the back
o Doubles as reserve buoyancy in case the wave piercing designed main hulls pierce too much wave.
o Doubles as a racing dingy using TP Mast design also.
o BOA 6’ (fits under King bed in Master stateroom)
o LOA 15’
That’s about it… so far. I have plenty of details and if there is any interest, I’ll be glad to share some of those details.
Right now, the biggest technical challenges are:
1. Getting all the pieces on the trailer
2. Sealing between pieces – gaskets, tang and groove.
3. Transform on trailer or in-water. Both have their Pros and Cons.
4. Getting assembly time down – I want it to be assembled with little technical knowledge (owner) using a check off sheet and a couple of men (hired help) and to be assembled or disassembled within about a half day. Idea being…
a. Sailing in Penobscot bay
b. Day 1 - Trailer and transform (or transform and trailer)
c. Day 2 and 3 – Travel to Southern Florida
d. Day 4 – Transform and launch
e. Day 5 – Bahamas and beyond.
Here are some views of the model. I will be uploading a low-resolution video of the Z40 Roadster to YouTube shortly and a 720p video is being generated now and should take about a month.
Let the darts fly! And if you insist on saying my baby is ugly or stupid… at least be descriptive to the area that offends your sensibilities. I’d like to learn something.
I am not an artist. I am an aerospace engineer specializing in structural analysis using composite materials. Meaning, everything has been thought out till I’ve drilled down to China. HOWEVER, I am not a marine architect and I don’t have the practical sailing, designing and building experience that is the gold mine of this forum. There are almost no details that have a cosmetic only reason, so you might find the design rather bland compared to other artist renderings on this site. On deeper inspection you may find a beauty in its Teutonic detail, multi purpose utilization of components, its Transformer abilities and its absolute efficiency of using every cubic inch to the fullest. It is by no means a fully realized design and has some challenges to overcome. But that is part of the enjoyment for me.
Some of my ideas are rather radical and come directly from the aerospace industry. That doesn’t mean I’m certain they’ll work, but I’m willing to air them here so practical minds can throw darts… hopefully constructively!
So here we go…
My Criterion – in order of importance are…
1. Safety
2. Trailerable
3. Largest boat possible.
4. Able to single hand.
5. Speed
6. Comfort
My early inspirations were the designs by Woods. Strong, beautiful boats from an architect with a great reputation. How could I go wrong? Unfortunately, his Skua at 30’ and Sango at 25’, although trailerable, were just not something I’d want to live aboard. Any of his larger designs have to be planted in the water to stay.
Trailerable – Here are my thoughts on trailerable. I live in the United States. And I can imagine wanting some variety to my sailing grounds. I’d like to sail the Bahamas and Caribbean in the winter, Penobscot Bay in the summer, the Mexican Rivera in the winter and the Inside and Outside passages between Seattle and Denali in Alaska in the summer. Maybe throw in some Great Lakes time and even put in, in Jackson Lake in the Tetons. Anyway… you get the idea. From a safety standpoint, I also want to get it out of the water and head inland during the hurricane season. I don’t want any cordwood of mine on the shores of Louisiana! For those of you not familiar with these places… well they’re a long ways away from each other… and some not by water!
Well, trailerable gives me some definitive maximum dimensions. It must fit within 40’ x 8.5’ x 13.5’ when on the trailer. Apparently, there is some wiggle room on the width here, but in some locations here… there isn’t! So, for the moment, I’m sticking with 8.5’. Among many other reasons (for me) this pretty much rules out monohulls and trimarans.
Comfort - Although down on the list, here is what I mean for comfort. I want to be able to live on it… period. Not camping, not roughing it. A shower I can stand in and a bed I don’t have to crawl into are a must. I don’t want to duck much but I’m only 5’7” so that isn’t much of an issue anyway. I want to entertain guests… basically, I want to live 2, sleep 6 and entertain 20.
This requires a hard bridge deck! This drove me toward the Sango’s articulations. Unfortunately, they just simply won’t scale and still fit into the box given the 7’ head room requirements I want. I briefly entertained the scissor scheme, but again it takes up way too much volume for that articulation when the only time that volume is used is during the expanding. So, I decided on the sliding beam concept similar to the Skua.
Speed versus Single Handing versus… well SPEED
This one burned the midnight oil many times. I like speed. Although I want to race it, I want to live on it and that means single handing most of the time… or assuming, at least, that in the worst of conditions, it still must be single hand able. I also want to be able to use it for as long as I can stand up… 70’s, 80’s… Maybe I can still push buttons into my 90’s. I’ve daydreamed over the likes of Hydroptère, Orange, Playstation, BMW’s America’s cup and just about every architect who offers plans or techniques. Nothing had the exact combination I wanted. And my 401k plan isn’t what it used to be. So, here I am… rolling my own. If I get everything down on this thread, you should see a lot of different influences. In the end, I centered on two designs that are my driving force for realistic speed… The Z40 Roadster is based mainly on parameters gleaned from the Extreme 40 and the Gunboat 48. By aiming high, I hope to at least break 20 knots in ideal conditions.
Design
I am still relatively early in the design spiral and have only made several cycles. My analyses include simple closed-form solutions, mechanics of materials methods, LPT theory and Dave Gerr’s scantlings in spread sheets. Yes, I know, he clearly says his scantlings do not apply to catamarans. I am mainly using it for ball park sizing, weights and cost analyses at the moment and no more. However, if anyone is willing (and able) to quantify that disclaimer, I would greatly appreciate it. A single hull falls within his acceptable dimensions, so I’m assuming (for the moment) that his disclaimer is due to the high stress concentrations incurred by cross beams that his scantlings do not address.
So without further fan fare here is how it stands (at the moment)…
LOA = 40’
BOA = 23’ (Collapsed 8.5’)
Hull Beam = 4’
Maximum displacement = 13,000 lbs - I want to make sure it is possible to tow with the Dodge/Ford/GM 350/3500 class of pick-up trucks using a 5th wheel configuration. As you’ll see, the 5th wheel configuration will be required as I have to move the trailer wheels far back from the balance point for height reasons and thus too much weight would be on the hitch.
So far weight is a growing target. I am currently experimenting with resin infusion methods to try and get the fiber density up. At the 35% number Dave Gerr states the boat is just plainly not feasible. However, if I can get near the fiber percentage claimed by resin infusion, and with the following accounted for…
• All fiberglass
• All Epoxy
• Foam core
• Windows (probably UV protected Lexan)
• Teak or artificial teak decking (may have to go)
• Engines
• Batteries
• Water
• Fuel
…AND the optimistic resin infusion fiber density, I have a gross weight before people of about 8500 lbs.
TP Mast Design
If you’ve already seen the pictures, you’ve probably already noted the masts (Plural). To my knowledge, I’ve not seen this configuration before, but I’m sure if it’s out there, someone here on this forum has either designed it or knows about it. Please let me know. I’ve seen many free standing (Schionning) and some with cross pieces (Yves Parlier’s “Médiatis Région Aquitaine”) so I’m coining the phrase TP Mast. The configuration solves many problems.
Pros
1. No huge support structure to hold a center mast.
2. No huge support structure to hold free standing bi-plane masts
3. Triangulation (strongest form in nature or man-kind)
4. Wing masts have no supporting shrouds for lateral stability.
5. Masts can rotate 360 degrees as many times as necessary.
6. Main sails are furled AROUND the masts.
7. 150% Genoa are furled around dual forestays.
8. Redundant forestays and backstays for safety and strength
9. Masts are stepped on rigid posts above the deck.
10. Masts can be stepped using the booms and dual anchor lasses. (Usually something in the size range requires a crane)
11. Due to the lower center of wind pressure and tilt of masts, more sail can be carried than a conventional single mast.
12. Lower windage with less shrouds and weathervaning of mains when sails are lowered.
13. Masts can be lowered to clear bridges while motoring.
Cons
1. Interference of multiple sails decreases efficiency of sails
2. Wind speeds are lower at lower heights. Sails aren’t as tall as a conventional design.
Just to give perspective for item 10 above. At the full gross weights and each using 100% foresails… the 13,000 lbs Z40 Roadster can carry slightly more sail area than the 17,700 lb Gunboat 48. They will both start lifting the windward hull at the same wind pressure. In this configuration the Z40 Roadster can carry 1650 square feet of sail! Hopefully, this will overcome the inefficiencies described in the Cons.
Oh! Almost forgot the amenities…
• Two queen size births in the hulls.
• 108 sq ft for the Master stateroom with King size bed forward in the bridge deck. Most Admirals (that I’ve read about) clearly dislike the “living in a cave” feel associated with living down in a monohull or even worse in a claustrophobic catamaran. This Master stateroom has panoramic views of your favorite anchorage.
• 120 sq ft in the Galley
• No, interior sitting, dining area – a deficiency to some, but then I don’t plan on sailing in cold climates WHEN it’s really cold. My suth’n blood would freeze solid.
• 120 sq ft in outside sitting, dining area with seating for 10 and another 10 could easily “join” the conversation on top of the hulls.
• 34 sq ft main head with full size standing shower (30” x 30”).
• 36 sq ft Master head with shower (and maybe whirlpool bath) if weight can be balanced. The Admiral likes baths!
• Full walk in Master closet… guess who?
• 32 sq ft shop / office / dual bunk beds area.
• 3’ bridge deck to water clearance for reduced pounding
• 6.5 to 7’ headroom throughout
• The bridge deck roof lowers for “spirited” sailing for reduced windage, structural stiffness and looks. It can be raised while sailing, but the windward foresail cannot be fully extended (only about 100%). Hard windows fold into roof. “Think” modern hardtop convertibles (BMW 3 Series) NOT popup campers.
• Hardtop Bimini
o Can be slid forward atop roof for full sun into the seating area.
o Can be slid back and fastened to hand railing when the roof is lowered… have to see the pictures.
o Can be slid back and fastened to the traveler when the roof is up… again see the pictures.
• Dual cockpits in rear corners. Unrestricted sight lines (when top is down) to all points.
• All control lines will be below decks and lead aft to the cockpits for single handing.
• Steering, I’m thinking about an aircraft joy stick type arrangement. Requires less room than a wheel, and with more feel. Also will be able to have multiple places for “joy sticks” that are mechanically attached… both cockpits, one inside the Master stateroom… maybe others.
• Also, emergency tiller can easily be attached to the top of the rudder and still sail from the cockpits.
• Rudders are offset to the outside of the hulls for egress and for improved efficiency when heeling. They also flip up if struck.
• It also uses swing keels instead of dagger boards that also swing up if struck.
• Engines are electric (so far) and will be housed near the fore/aft centerline to
o facilitate turning on its center point
o protected props. Props should be fully above the bottom of the hulls.
o Permit backing and beaching the stern and allow dry walk off/on.
• Hard dingy is stowed forward under the bridge deck.
o No ugly dingy hanging off the back
o Doubles as reserve buoyancy in case the wave piercing designed main hulls pierce too much wave.
o Doubles as a racing dingy using TP Mast design also.
o BOA 6’ (fits under King bed in Master stateroom)
o LOA 15’
That’s about it… so far. I have plenty of details and if there is any interest, I’ll be glad to share some of those details.
Right now, the biggest technical challenges are:
1. Getting all the pieces on the trailer
2. Sealing between pieces – gaskets, tang and groove.
3. Transform on trailer or in-water. Both have their Pros and Cons.
4. Getting assembly time down – I want it to be assembled with little technical knowledge (owner) using a check off sheet and a couple of men (hired help) and to be assembled or disassembled within about a half day. Idea being…
a. Sailing in Penobscot bay
b. Day 1 - Trailer and transform (or transform and trailer)
c. Day 2 and 3 – Travel to Southern Florida
d. Day 4 – Transform and launch
e. Day 5 – Bahamas and beyond.
Here are some views of the model. I will be uploading a low-resolution video of the Z40 Roadster to YouTube shortly and a 720p video is being generated now and should take about a month.
Let the darts fly! And if you insist on saying my baby is ugly or stupid… at least be descriptive to the area that offends your sensibilities. I’d like to learn something.
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