Wood Over Foam (WOF) Construction

[Dasboatman]

"I can't speak for everyone Bob, but I would really enjoy a build thread for one of your WOF scales."

68Bud,

You asked for it.

OK, Here we go. I had actually taken a bunch of pics of the last MHR 8255 build I did for this purpose, but promptly erased them trying to do something creative with them and didn't follow the K.I.S.S. Principle. If the hull appears significantly different between pics - it's probably because I don't have an adequate pic of a Scale boat to show, and am using another hull for show and tell. Please feel free to ask any questions anyone has, and I'll try to answer.

I started boating in 1970. Had built and flown competitive control line and free flight airplane since I was about 5 before that with my Father - Gus Johnson.

First boat was a fiberglass hull called L'l Hoss with a side port K&B 40 in it. Hull was very popular in Miami area back then and there were many built and raced with the Racing Association of Miami weekend gatherings back then. My Friend, Don Pinckert, was basically assembling a package of hull, awailable hardware - including a Stinger rudder assembly and prop, Marine Specialties 5" alum motor mount. 3/16" X 24" case hardened Stainless steel shafts from Dumas Boats, and ball bearing for the shaft to ride in supported by two thicknesses of K & S tubing - most all parts available from The LHS - Orange Blossom Hobbies at the time. Don also provided specific instructions to set up the hull, so there were a lot of competitive boats racing, very closly matched, any given weekend. Probably the most fun I ever had racing boats. Back then it was more of an all day social event at the club lake with beer and Hot Dogs available to add to the festivities.

Don later started making flat kits for the Mixer and Gator series of outriggers - WOF. These were the first boat kits I had seen using white foam and aircraft grade birch plywood for construction.

I was stationed in Norfolk, VA back then and was modeling with a good Friend - Frank Blanchard that I had met at the LHS - Zephyr Miniatures. Frank and I liked the idea of building WOF, so, after seeing Don's kits, Frank decided to build a round nose hull. As I recall - that was the first round nose hydro, WOF hull built. He used a white t-shirt and polyester resin to cover the deck with, birch ply on sponson surfaces, hull bottom and after plane non trips. This was prior to Scale or Sport 40 rules being developed. We raced classes by similar engine displacement - Hydro or Mono back then. About 1971 - 1972 was the era.

Frank purchased a 4' X 8' x 4" sheet of Dow Chemical Styrofoam, which is a polystyrene material. Frank also had a well equiped garage shop with a band saw, belt sander, and drill press - - Heaven for this poor sailor. It cut, carved and sanded very well - I still use it almost 40 years later.

Here are a couple teaser pics of the start of a Scale boat. More a bit later. CHEERS !!! Bob

 

[Dasboatman]

Tools I use:

I have a 10" band saw that will only cut material a max of 3" thick, so I buy 3" thick Dow Chemical Styrofoam. I purchase Styrofoam 4' X 8' X 3" from an building insulation company - Ryder Insulation here in the Houston area. I have never tried the pink color or other types.

I have used various white foams over the years. I use it today in the after plane to try and keep aft weight down. The best I found was from a company that made structural decorative moldings like columns, and ceiling moldings. in 2#/cu. ft. and 4#/cu.ft material. This company was Star Foam in San Marcos, CA. I haven't found white foam that good since. Now I comshaw white foam from a large department store I frequent. Lots of their Chinese furniture uses white foam in shipping packages. Pic attached of my last haul.

Aircraft grade birch ply 1/32", 1/16" 3 ply, and 3/32" 5 ply.Used Lone Star Balsa ply for years, but they no longer have 4'X 12" ply available, so I have been buying from www.nationalbalsa.com the last couple of years.

I build with Bob Smith Industries 30 Min. Slo-cure Epoxy available from LHS, usually with their name on it. I use medium Zap-A-GAP as instant straight pin. I don't use any 5 minute epoxy - personal preference.I nail similar pieces together with small brads, cut to shape on band saw, and sand onvertical oriented belt sander to make sure everything is square to start.

I start with a Newton Paint plan for over all shape of hull and graphics. I have significantly changed hull center section side shapes (airfolis), sponson angles, sponson dihedral and/or anhedral, and ride plates over the years. The first Scale boat I built was a MHR 7474 U-74 VALU*MART in 1975. I ran an OPS 60 engine with an Octura Kool Clamp, 45 steel flywheel, & universal. and used a series 70 (I believe) carb on it. This was a car motor at the time - before anyone had a Marine version available. Also ran Super Tiger G-65 side exhaust back then too. Engine power has improved significantly since then so this changes the hull design. I also consider where the hull will be raced. My smooth California water hulls were not competitive when I moved to Florida which had move wave heigth and chop compared to California.

That's a really nice thing about a WOF build - they are easily changed to allow you to try something new. I had a Friend that could do miraculous things to a WOF hull with an air die grinder. Blue snow in Florida in July !!!!

Other fighting tools include a long blade kitchen knife to remove large sections of foam without using a belt sander or Stanley SURFOAM 21-295 file. An old hack saw blade is goo for this too for areas such as removing material previously cut on band saw that want to become a crowned deck area - jus need a little help. Long sanding blocks 12" X 3 1/2" X 1" thick wood with 30 grit paper on one sidem 60 grit on the other. I like black in color - hardwood floor sandpaper - it comes in rolls. Best I've ever used. Wisk away residual Styrofoam with a small wire brush.

OK, I know more pictures........

 

[Bill Gibson]

Hi Bob, ive now built a few WOF hulls and even kind of adapted a bit of WOF construction to a couple of framed up models and nothing beats surface area to glue parts-n-pieces to for STRENGTH! And talk about floatation! It really is a fun way to build a model...love that old pic of the "Hoss"! And i remember Orange Blossom Hobbies too!Ahhhh......memories!

 

[FloridaScaleBoater]

Aw,,, Now you chime in!!!!!!

Where were you when I needed you help the other day?????

Don Ferrette, on 01 December 2010 - 11:03 PM, said:

Dasboatman, on 01 December 2010 - 10:22 PM, said:

"And this is coming from a guy who's looking for "a decent picture of the deck, of the U-40 "plane Jane" Miss Houston"

Hey Don,

Thanks for the information. He has been bustin' my chops for me even thinking of doing my latest 8255 as Miss Houston - - and NOW - I HEAR This !!! Watch him try to backslide out and say the paint job is for someone else's hull. He wanted me to paint mine as 8255 '83 U-100 Miss Rock - - four different colors , and all the graphics in the world on it. Ah Ha !!! We have your number now Bellinger !!!!! Har, Har !!!! CHEERS !!! Bob

1983 U-40 Miss Houston (white).JPG 1983 Miss Rock.jpg

http://www.intlwater...ndpost&p=388477

Stone cold BUSTED!!!

Hey, Bill Gibson,,,,, Where you at to help me out here?????

 

[Bill Gibson]

Aw,,, Now you chime in!!!!!!

Where were you when I needed you help the other day?????

Don Ferrette, on 01 December 2010 - 11:03 PM, said:

Dasboatman, on 01 December 2010 - 10:22 PM, said:

"And this is coming from a guy who's looking for "a decent picture of the deck, of the U-40 "plane Jane" Miss Houston"

Hey Don,

Thanks for the information. He has been bustin' my chops for me even thinking of doing my latest 8255 as Miss Houston - - and NOW - I HEAR This !!! Watch him try to backslide out and say the paint job is for someone else's hull. He wanted me to paint mine as 8255 '83 U-100 Miss Rock - - four different colors , and all the graphics in the world on it. Ah Ha !!! We have your number now Bellinger !!!!! Har, Har !!!! CHEERS !!! Bob

1983 U-40 Miss Houston (white).JPG 1983 Miss Rock.jpg

http://www.intlwater...ndpost&p=388477

Stone cold BUSTED!!!

Hey, Bill Gibson,,,,, Where you at to help me out here?????

HEY! I GOT YER BACK, BROTHA BOATA! :lol: Its ME BOB...ALL ME! :lol:

 

[68Bud]

Tools I use:

I have a 10" band saw that will only cut material a max of 3" thick, so I buy 3" thick Dow Chemical Styrofoam. I purchase Styrofoam 4' X 8' X 3" from an building insulation company - Ryder Insulation here in the Houston area. I have never tried the pink color or other types.

I have used various white foams over the years. I use it today in the after plane to try and keep aft weight down. The best I found was from a company that made structural decorative moldings like columns, and ceiling moldings. in 2#/cu. ft. and 4#/cu.ft material. This company was Star Foam in San Marcos, CA. I haven't found white foam that good since. Now I comshaw white foam from a large department store I frequent. Lots of their Chinese furniture uses white foam in shipping packages. Pic attached of my last haul.

Aircraft grade birch ply 1/32", 1/16" 3 ply, and 3/32" 5 ply.Used Lone Star Balsa ply for years, but they no longer have 4'X 12" ply available, so I have been buying from www.nationalbalsa.com the last couple of years.

I build with Bob Smith Industries 30 Min. Slo-cure Epoxy available from LHS, usually with their name on it. I use medium Zap-A-GAP as instant straight pin. I don't use any 5 minute epoxy - personal preference.I nail similar pieces together with small brads, cut to shape on band saw, and sand onvertical oriented belt sander to make sure everything is square to start.

I start with a Newton Paint plan for over all shape of hull and graphics. I have significantly changed hull center section side shapes (airfolis), sponson angles, sponson dihedral and/or anhedral, and ride plates over the years. The first Scale boat I built was a MHR 7474 U-74 VALU*MART in 1975. I ran an OPS 60 engine with an Octura Kool Clamp, 45 steel flywheel, & universal. and used a series 70 (I believe) carb on it. This was a car motor at the time - before anyone had a Marine version available. Also ran Super Tiger G-65 side exhaust back then too. Engine power has improved significantly since then so this changes the hull design. I also consider where the hull will be raced. My smooth California water hulls were not competitive when I moved to Florida which had move wave heigth and chop compared to California.

That's a really nice thing about a WOF build - they are easily changed to allow you to try something new. I had a Friend that could do miraculous things to a WOF hull with an air die grinder. Blue snow in Florida in July !!!!

Other fighting tools include a long blade kitchen knife to remove large sections of foam without using a belt sander or Stanley SURFOAM 21-295 file. An old hack saw blade is goo for this too for areas such as removing material previously cut on band saw that want to become a crowned deck area - jus need a little help. Long sanding blocks 12" X 3 1/2" X 1" thick wood with 30 grit paper on one sidem 60 grit on the other. I like black in color - hardwood floor sandpaper - it comes in rolls. Best I've ever used. Wisk away residual Styrofoam with a small wire brush.

OK, I know more pictures........

Hey Bob, thanks for starting the WOF thread, this is really interesting stuff. Looks like from the pictures there are a few different hulls going together. Couple of quick questions...How much of the Newton plans do you use for the templates? What is the AOA on your sponson mod?

 

[Dasboatman]

"Hey Bob, thanks for starting the WOF thread, this is really interesting stuff. Looks like from the pictures there are a few different hulls going together. Couple of quick questions...How much of the Newton plans do you use for the templates? What is the AOA on your sponson mod?"

68Bud,

You are welcome. As with most things - I jumped into this so I'm using pics I have on hand. I see two different boats so far. My first post is L to R: L'l Hoss, next two are the 8255 Scale boats. Second post: first 4 pics are of a Sport 42 designed by Jack St. Clair that I built in 2005 or so.Last pic on it's nose is an 8255 hull w/o deck. The two 8255s were started Aug 2006.

I use the overhead view of Roger's paint plan for hull dimensions. The side view really only for general depth and shape. The first thing I do is eliminate the majority of nose rise in the center section (Ram Wing) - I can't live with all that positive angle of attack. Sponsons are purely my own - heavily influenced by Don Pinckert. I have been using a sponson drop of 1" lately here in Texas. Have been as shallow as 7/8" for California water; 1 1/4" for Florida water. I'm not smart enough to measure an accurate sponson angle in degrees. When I block up the hulls I use wood blocks to position everything while the epoxy cures. Sponson angle for me is typically sponson bottom is 1/2" off table, 6" forward of the rear sponson plate (touch), with the transom blocked to the height I think it will run at.

The first 7704 U-4 I built in California had too much nose rise and was a kite at speed. I completely changed the center section for my second U-4. I have built about five 8255s.First one was designed by Gus Johnson - I finished it, Jack St. Clair rigged and painted it - and it did it's very best to drive both of us mad. No matter what was tried - it showed little improvement. It was run through a band saw to put it out of it's misery. Next one was Gus U-8 Executone - solid shaft running in ball bearings. My Oberto was a heavily modified Gus hull. Different center section, different sponsons, 1/4" square drive flex drive. It was a joy to drive from the first test hop, and 9 years later is still my #1 race boat.

Pics attached are: my Oberto at the 2010 NAMBA Nats, Rick's Coors one of the two 8255s I built last. Final pic is my unfinished mate to Rick's Coors. I'm trying to figure out how to use the Gallery function I'm eating up attachment space and found out the other night what happens to attachments deleted to make more space for new pics. CHEERS !!! Bob

 

[Kez]

Hi Bob,

Great thread! I will be borrowing your techniques to build my next scale (U-95). I like the idea of using the white foam in the aft section to help with balancing the boat. The white foam available at Home Depot is the expanded bead type and will not be suitable for construction. I will scrounge around local furniture stores for the packing materials.

I noticed in your photos that you are using a hard mount. Do you find any issues with vibration related stress cracks?

What is the noise levels compared to a glass or framed hull? With WOF, the hull will probably not resonate engine noise like a glass hull does.

Thanks,

kez

 

[FloridaScaleBoater]

Hey Bob,

In post #2 The picture of the 8255 scale.

This is a picture of mine http://www.intlwaters.com/index.php?showtopic=43304#

Ya know how I can tell???

 

[Dasboatman]

"Hey Bob,

In post #2 The picture of the 8255 scale.

1. This is a picture of mine?

2. Ya know how I can tell???"

Hey Rick,

Yes, Moose Breath, that one be yours. What he is referring to is the cut out in the starboard Red Oak motor mount wedge to allow room for throttle linkage and bellows. I cut his out on my band saw prior to epoxying in the wedges. Seems I failed to do this on my own hull and had to cut mine by hand. What a significant pain in the ARSE. It's fixed now, bleeding stopped, scar will be there for years.

I see a large hunk of coal coming your way about the 25th. Ho, Ho, Ho !!!

Hey KEZ,

I have played with Lord style isolation mounts mounted vertically and horizontally. Ultimately I went back to the solid Octura Omni mount screwed and epoxied to red oak wedges. I don't see any stress cracks, and I believe the noise level is comparable with glass hulls running rubber isolator style mounts, or possibly more quiet in the WOF hulls.

The last glass hull I owned was the L'l Hoss in my first post, so I don't have sufficient data. I would anticipate an epoxy glass hull with solid mount would resonate very loudly.

CHEERS !!! Bob

 

[Dasboatman]

Hey 68Bud,

It dawned on me that you would probably have preferred to see a round nose style hull construction pics. This is my Classic Thunderboat U-444 Shorty's BBQ, using my own plan, that I built last year. We won't mention that it's not nitro - construction didn't notice the difference. Tub is offset to Port to allow the tuned pipe and header to clear. Tub is 6 5/8" wide. Hull is 49" long, right at 20#. I used Styrofoam through out - my target weight was 17# - OOPS !!! Pics are in the Gallery "Dasboatman: Wood Over Foam (WOF) Construction" I think:

http://www.intlwaters.com/index.php?app=gallery&module=user&user=2139&do=view_album&album=1082

The booms seen extenting from the rear plate of sponsons being formed (in pics) are 3/8" X 3/4" Maple that span the rear sponson plate extending across the tub bottom and into the tub rails. This engine is also hard mounted using a CC Racing motor mount with the Lord rubber isolators removed. Boats first race was the 2010 NAMBA Nationals. It runs an adjustable solid drive shaft running in ball bearings - - "Don Pinckert's Power Drive". CHEERS !!! Bob

 

[68Bud]

Hey 68Bud,

It dawned on me that you would probably have preferred to see a round nose style hull construction pics. This is my Classic Thunderboat U-444 Shorty's BBQ, using my own plan, that I built last year. We won't mention that it's not nitro - construction didn't notice the difference. Tub is offset to Port to allow the tuned pipe and header to clear. Tub is 6 5/8" wide. Hull is 49" long, right at 20#. I used Styrofoam through out - my target weight was 17# - OOPS !!! Pics are in the Gallery "Dasboatman: Wood Over Foam (WOF) Construction" I think.

The booms seen extenting from the rear plate of sponsons being formed (in pics) are 3/8" X 3/4" Maple that span the rear sponson plate extending across the tub bottom and into the tub rails. This engine is also hard mounted using a CC Racing motor mount with the Lord rubber isolators removed. Boats first race was the 2010 NAMBA Nationals. It runs an adjustable solid drive shaft running in ball bearings - - "Don Pinckert's Power Drive". CHEERS !!! Bob

All I can say is Wow! Killer boat Bob! And you're right, I do prefer round nose hulls, but I appreciate the pickle fork boats too until the enclosed canopies and turbines took over. I don't know if you remember but you provided me with some pictures of the Redman Too for my scratch built sport 20. I appreciate the help and have attached a picture of it below. We also discussed my gas sport hydro located here http://www.rcuniverse.com/forum/m_6574785/anchors_6574785/mpage_1/key_/anchor/tm.htm#6574785 I really like what you did with the offset tub and the "vented" sponsons on your Lauterbach style hydro. I'm curious how an adjustable solid shaft works, could you show us some pictures? Thanks,

Scott

 

[FloridaScaleBoater]

Scott;

Your boat looks great

Don't want to hijack Bob's thread here,

But could you share some interior, and bottom photo's of that sweet lookin little boat.

Rick

 

[Dasboatman]

"I'm curious how an adjustable solid shaft works, could you show us some pictures?"

Hey Scott,

Yes I do recall. The Red Man turned out very nice. Pics of the big boat look good too.

This is the first time I have used the "Pinckert Power Drive". It surely is NICE to be able to simply loosen the strut and guide bracket attached to the firewall and move the sucker up and down.

First pic shows the shaft and tube make up. Shaft is a 25" 3/16 case hardened shaft from Gary Jensen. There are eight 3/8" OD instrument bearings spaced by brass tubing(3/8" OD) There are 4 bearings within the length of the strut, and a single bearing at each spacing leading to male end of the Octura Universal. Bearing tube is 3/8" ID with next larger size of tubing over it Full length -extending through the strut. There are two thicknesses of brass tubing over the nose of the strut extension.

Strut is an Octura Stainless steel long with the skeg removed. When you make the cut in the hull bottom and build a tunnel, make sure the stuffing tube will not contact hull bottom or fabricated tunnel when you adjust the strut through it's higest to lowest position. I did have to drill through the strut to enable the double thick brass tubing to pass. CHEERS !!! Bob

 

[68Bud]

Bob, to say you think outside of the box is an understatement! That is some innovative engineering, very impressive! I am wondering how you seal the shaft where it passes thru the hull? How often do you lube the driveshaft and what type of lube do you use?

 

[Dasboatman]

Hey Scott,

Thank you, but the engineering behind the "Power Drive" is Don Pinckert - I simply followed his direction. He told me that he had written an article that was published in IMPBA Roostertail some years ago. I was out of boating 1980 - 1987 boring holes in the ocean on board USN Submarines, and Staff duty at SUBPAC. Shortly before he told me about this, I decided to revisit solid shaft in an Ira Cotton round nose I'm playing with. The two attached pics are the way we did it years ago ( and how I did it just over a year ago) - you can see what a significant pain in the arse this is to change - I have changed them a lot over the years.

My shaft isn't sealed, so water does come into the tub area. But the hull is WOF, so only the tub area provides any floodable volume, and doesn't amount to much weight. You could use clear silicone to seal it at the firewall once you get the drive line set where you want it. The pic of the firewall mounted guide with elongated adjustment slot is Don's Pickle Daytona which is a fiberglass hull. It's flotation is maintained by 'pool noodles' or the like.

The ball bearings I use are sealed. Post run, I loosen the male universal and wheel collar set screws and pull the shaft, bearings and bearing spacers out of the stuffing box, flush all with WD 40, lube with Corrosion X, and install back in the hull. I do no maintenance during the race weekend.

I forgot to say that I'm using lifting props with the hard shaft boats, i.e. 14XX, 16XX, and even playing with 21XX. Start with a 1465 in .67 Scale boat. There is a heavily modified 1470 on the Classic Thunderboat w/stock Zenoah 260 PUM.

CHEERS !!! Bob

 

[Dasboatman]

I posted pic of my Wood Over Foam build for a Classic Thunderboat Here:

http://www.intlwaters.com/index.php?app=gallery&module=user&user=2139&do=view_album&album=1082

This hull was built in late 2009 is 49" long and 25" wide. Ready to run weight is right at 20#. No lead was added to balance to C/G. If I build another one I would reduce some of the weight by boring some lightening holes in the front apron, and afterplane non trips Styrofoam, and rethink the Red Oak motor mount area.

Sponson inside, and rear sponson plates are 3/32" five ply Birch plywood. Hull bottom, sponson bottoms and non trips are sheeted with 1/16th Birch 3 plywood, Deck and afterplane are sheeted with 1/32" Birch 3 ply. Transom is 3/32" five ply (outside full width) - the area inside the tub sides are three thicknesses of 3/32" five ply laminated together using 30 minute epoxy. I use 30 Min. Slow cure epoxy to construct, seal with West Systems 105 Resin 206 Hardener.

I'll answer any questions you have.

The really nice thing abot a WOF build is - - You can build what appeals to you, not what someone kitted or built to suit themself. So many choices, so little time. CHEERS !!! Bob

 

[Kez]

I posted pic of my Wood Over Foam build for a Classic Thunderboat Here:

http://www.intlwaters.com/index.php?app=gallery&module=user&user=2139&do=view_album&album=1082

This hull was built in late 2009 is 49" long and 25" wide. Ready to run weight is right at 20#. No lead was added to balance to C/G. If I build another one I would reduce some of the weight by boring some lightening holes in the front apron, and afterplane non trips Styrofoam, and rethink the Red Oak motor mount area.

Sponson inside, and rear sponson plates are 3/32" five ply Birch plywood. Hull bottom, sponson bottoms and non trips are sheeted with 1/16th Birch 3 plywood, Deck and afterplane are sheeted with 1/32" Birch 3 ply. Transom is 3/32" five ply (outside full width) - the area inside the tub sides are three thicknesses of 3/32" five ply laminated together using 30 minute epoxy. I use 30 Min. Slow cure epoxy to construct, seal with West Systems 105 Resin 206 Hardener.

I'll answer any questions you have.

The really nice thing abot a WOF build is - - You can build what appeals to you, not what someone kitted or built to suit themself. So many choices, so little time. CHEERS !!! Bob

Hey Bob,

When you change the angle of your adjustable hard shaft, do you change the angle of your engine mount as well? Or do you let the U-joint adapt to the angle?

Also, did you offset the strut? (I can not tell from the pictures). If so, can you share how much was the offset?

Thanks,

kez

 

[Dasboatman]

Hey Kez,

Loosen the strut bolts and the firewall guide, put the hull on it's nose and move the strut where you want it. Shaft thrusts on the universal in my boats. Just let the universal adapt to the angle, I have never adjusted the engine angle once set. Have not been moving more than 1/8 " up or down, so the angle does not get excessive. When I initially set up the strut depth on the CT, it was set just a little deeper than I thought the hull would ride - mainly to keep it from blowing over in initial testing. The elongated slot in Octura strut was centered in strut bracket. Right now it's all the way up (shallower depth) and I'll test by raising it more to see where the hull starts to lift, then go down a touch. I'm still playing with props on the hull also. I have blown the CT over only once testing without the cowl while we were searching for a good match prop at the Nationals. Hull is very solid with cowl in place. One of my goals with this hull was to have it ride high and dry with the tail up in the air - - a good clean three point. There is a heavily modified Octura 1470 on it presently.

CT hull shaft is angled 1/4" to port at prop, universal on hull C/L. My Oberto driveline is offset 1" to port of hull centerline and parallel. Next hull we tried 1/2" to port and parallel , and the last few have been right down centerline. CHEERS !!! Bob

 

[just for fun]

Dasboatman, Do you see any reasons stopping one from building any hull shapes using this method? Just thinking out loud.

Phil Fowler