Pay N Pak

[Hydro Junkie]

I was wondering how I would go about building a jig for the Pay n Pak? This is my first build and I want it as straight as I can get it. Thanks for any info. John

Whatever jig you use I recommend you make it out of heavy duty water resistent particle board. That stuff is really dead and plywood tends to warp. I have always used Liquid Nails and clamps. I always get a smaller pice of particle board, cover it with wax paper and build the sponsons on that. Then I push pin the sponsons on to the main jig that you already the bottom and transom on. That way you can really do a good job of measuring to make sure you get a straight boat.

I think the particle board you're talking about is called MDF(no I don't know what it stands for). Lowes or home depot shelving dept. 1" thick cut to width on a table saw. And use the wax paper so you don't glue the boat to the jig.

Glenn

MDF is a medium density fiberboard that combines wood fibers and glue under pressure to make a material considerably stronger than the more commonly used particle board, What I would do for a jig is to cut MDF to the required width, screw that to 1X1s or 2X2s and then rip the scrap and screw that to the 1X1/2X2s as supports. This gives you an elevated work surface that can be clamped to with no fear of crushing it. This picture has a couple of them, back row right two boats are both sitting on one

 

[R.J.West]

Thats the Dumas pay n pak sport 20 that I'm working on. I just got the decks on, and havent gotten to the nose blocks yet..I'l keep ya'll updated with pics as I go along..The turnfin pic is kinda decieving because of the angle of the camera However the turnfin when mounted angles inward about 6 degrees, and the fin itself has that curve inward also..Its kinda cool & should work with this hull, either way its better than the "turn-fin" that dumas supplies.

I used the dumas mounting bracket to mount the fin, and also as a generic mounting location for any other turnfin I may use or make in the future in case this one doesnt work....

 

[griz2575]

Again thank you guys. After the info you gave me I feel alot more confident in building my Pay N pak. Iwaters has the best group of people!!!!!

 

[Bill Gibson]

Again thank you guys. After the info you gave me I feel alot more confident in building my Pay N pak. Iwaters has the best group of people!!!!!

Griz, just remember that anything you might screw up during the building process, chances are....WE ALREADY HAVE...USUALLY MORE THAN ONCE! :lol: Were here for ya man!!!

 

[griz2575]

Again thank you guys. After the info you gave me I feel alot more confident in building my Pay N pak. Iwaters has the best group of people!!!!!

Griz, just remember that anything you might screw up during the building process, chances are....WE ALREADY HAVE...USUALLY MORE THAN ONCE! :lol: Were here for ya man!!!

Cool Thanks

 

[R.J.West]

Heres a pic of my Dumas Pay N pak 20.

First, I cant beleive that they actually mention using wood screws for the turn fin & rudder...I'm using Speedmasters .21/40 rudder and square bottom strut. The turnfin I picked up from a hong kong seller on ebay. I used 6-32 T-nuts for my turnfin mount (1/8 ply doubler on inside)

I was going to go ahead and use this engine mount, instead of the dumas one...

I wanted to keep the Dumas flavor and built it according to the plans more or less. What I've done was to make cutouts in all the frames & bulkheads in an attempt to keep the weight down. I did add 1/8 square stock along the bottom like HJ says as well as the top deck, especially along the non trip chines.

My next step was to remove the bulkhead 7, and just make bulkheads 5 & 6 my radio box.

The hull feels really light as of now. However I took a bottle of drinking water, which weighs .09 ounces (.5liter) and its definately heavier than the hull....

I remember that the cowl took almost as long to build as the hull on my 40 size U-76, I'm pretty much expecting the same here......

Cool trick that I'l share, I used my wifes iron and by holding and bending the sponsons sides and decks, I was able to get a nice bend in them so that they may fit over curves better. Just sprinkle a little bit of water over the area you want to bend and put the iron over your 1/16 ply skin and gently pull up and pressing down on the iron you'l get a nice bend....

When I epoxied the decks on, I placed the hull upside down so that the epoxy would flow onto the underside of the deck, instead of flowing down over the frames....

Decking, sponson sides and bottoms can also be bent to fit just using hot water and taping the heck out of em(on the hull) and just walk away for a couple days. Room temp.-not some cold garage. Don't bother sanding the skins before you do this as it will raise the grain a little.

Glenn

Yeah its interesting that you mentioned that because after Ironed out my skins, the thought came to me to do just that, and it worked out great! I'm always looking for new ways to do things without getting into trouble w/the Mrs.

Keeps us updated on your build Griz!

 

[griz2575]

Heres a pic of my Dumas Pay N pak 20.

First, I cant beleive that they actually mention using wood screws for the turn fin & rudder...I'm using Speedmasters .21/40 rudder and square bottom strut. The turnfin I picked up from a hong kong seller on ebay. I used 6-32 T-nuts for my turnfin mount (1/8 ply doubler on inside)

I was going to go ahead and use this engine mount, instead of the dumas one...

I wanted to keep the Dumas flavor and built it according to the plans more or less. What I've done was to make cutouts in all the frames & bulkheads in an attempt to keep the weight down. I did add 1/8 square stock along the bottom like HJ says as well as the top deck, especially along the non trip chines.

My next step was to remove the bulkhead 7, and just make bulkheads 5 & 6 my radio box.

The hull feels really light as of now. However I took a bottle of drinking water, which weighs .09 ounces (.5liter) and its definately heavier than the hull....

I remember that the cowl took almost as long to build as the hull on my 40 size U-76, I'm pretty much expecting the same here......

Cool trick that I'l share, I used my wifes iron and by holding and bending the sponsons sides and decks, I was able to get a nice bend in them so that they may fit over curves better. Just sprinkle a little bit of water over the area you want to bend and put the iron over your 1/16 ply skin and gently pull up and pressing down on the iron you'l get a nice bend....

When I epoxied the decks on, I placed the hull upside down so that the epoxy would flow onto the underside of the deck, instead of flowing down over the frames....

Decking, sponson sides and bottoms can also be bent to fit just using hot water and taping the heck out of em(on the hull) and just walk away for a couple days. Room temp.-not some cold garage. Don't bother sanding the skins before you do this as it will raise the grain a little.

Glenn

Yeah its interesting that you mentioned that because after Ironed out my skins, the thought came to me to do just that, and it worked out great! I'm always looking for new ways to do things without getting into trouble w/the Mrs.

Keeps us updated on your build Griz!

I will and I am going to post build pics as well

 

[Mike Cathey]

Mike, does that work with full frame construction like what is used in a Dumas boat? I've only seen that done when a boat is built in three parts, the canoes and the center as separate assemblies. You haveme curious on this one so if you could give us a bit more info....

Hi,

All I've ever made are boats with the method I described above. I know that once you get the sponsons frammed up on the sponson main you can pop it off the jig and it's a lot easier to add the glueing strips for the chines, recovery pads and decking. Once the sponsons are attached to the main jig and the engine mains, nose block, afterplane framing and sheeting, the deck is sheeted and the whole thing is rigid I take it off the jig and then sheet the sponsons chines and recovery pads, everthing except for the running surfaces. Once I figure out what the angle of attack I want on the sponson running surfaces (for my boats I like about 3 degrees to start with) Then I add the gluing strips, block sand it and add the running surfaces.

Rocking the boat on the running surfaces on a glass top table or something equally level and then measuring the distance between the table top and the transom will give you a method of measurement to get you in the ballpark for angle of attack on the runninmg surfaces.

By the way none of the above was figured out by me. Thanks to John Logan and Russ Nachwiegh for taking the time to show me this stuff.

 

[R.J.West]

Mike, does that work with full frame construction like what is used in a Dumas boat? I've only seen that done when a boat is built in three parts, the canoes and the center as separate assemblies. You haveme curious on this one so if you could give us a bit more info....

Hi,

All I've ever made are boats with the method I described above. I know that once you get the sponsons frammed up on the sponson main you can pop it off the jig and it's a lot easier to add the glueing strips for the chines, recovery pads and decking. Once the sponsons are attached to the main jig and the engine mains, nose block, afterplane framing and sheeting, the deck is sheeted and the whole thing is rigid I take it off the jig and then sheet the sponsons chines and recovery pads, everthing except for the running surfaces. Once I figure out what the angle of attack I want on the sponson running surfaces (for my boats I like about 3 degrees to start with) Then I add the gluing strips, block sand it and add the running surfaces.

Rocking the boat on the running surfaces on a glass top table or something equally level and then measuring the distance between the table top and the transom will give you a method of measurement to get you in the ballpark for angle of attack on the runninmg surfaces.

By the way none of the above was figured out by me. Thanks to John Logan and Russ Nachwiegh for taking the time to show me this stuff.

I was sad when my folks yrs ago sold their glass kitchen table.

 

[griz2575]

Mike, does that work with full frame construction like what is used in a Dumas boat? I've only seen that done when a boat is built in three parts, the canoes and the center as separate assemblies. You haveme curious on this one so if you could give us a bit more info....

Hi,

All I've ever made are boats with the method I described above. I know that once you get the sponsons frammed up on the sponson main you can pop it off the jig and it's a lot easier to add the glueing strips for the chines, recovery pads and decking. Once the sponsons are attached to the main jig and the engine mains, nose block, afterplane framing and sheeting, the deck is sheeted and the whole thing is rigid I take it off the jig and then sheet the sponsons chines and recovery pads, everthing except for the running surfaces. Once I figure out what the angle of attack I want on the sponson running surfaces (for my boats I like about 3 degrees to start with) Then I add the gluing strips, block sand it and add the running surfaces.

Rocking the boat on the running surfaces on a glass top table or something equally level and then measuring the distance between the table top and the transom will give you a method of measurement to get you in the ballpark for angle of attack on the runninmg surfaces.

By the way none of the above was figured out by me. Thanks to John Logan and Russ Nachwiegh for taking the time to show me this stuff.

:blink:

What happens if you get more or less than the 3 degrees?

 

[Bill Gibson]

Mike, does that work with full frame construction like what is used in a Dumas boat? I've only seen that done when a boat is built in three parts, the canoes and the center as separate assemblies. You haveme curious on this one so if you could give us a bit more info....

Hi,

All I've ever made are boats with the method I described above. I know that once you get the sponsons frammed up on the sponson main you can pop it off the jig and it's a lot easier to add the glueing strips for the chines, recovery pads and decking. Once the sponsons are attached to the main jig and the engine mains, nose block, afterplane framing and sheeting, the deck is sheeted and the whole thing is rigid I take it off the jig and then sheet the sponsons chines and recovery pads, everthing except for the running surfaces. Once I figure out what the angle of attack I want on the sponson running surfaces (for my boats I like about 3 degrees to start with) Then I add the gluing strips, block sand it and add the running surfaces.

Rocking the boat on the running surfaces on a glass top table or something equally level and then measuring the distance between the table top and the transom will give you a method of measurement to get you in the ballpark for angle of attack on the runninmg surfaces.

By the way none of the above was figured out by me. Thanks to John Logan and Russ Nachwiegh for taking the time to show me this stuff.

:blink:

What happens if you get more or less than the 3 degrees?

Griz, thats a baseline...lotsa people have thier own preferences on AOA depending on the boat...again it all depends on how much absolute performance you want out of the boat...the truth is, with that particular boat, the more you want out of it, the more changes you will have to make and the time and work you are going to have to put into it..gotta remember that kit came out in the 1970s and raceboat designs have changed signifigantly since those days.....

 

[griz2575]

My goal is to have a pretty competitive sport 20

 

[Mike Cathey]

Mike, does that work with full frame construction like what is used in a Dumas boat? I've only seen that done when a boat is built in three parts, the canoes and the center as separate assemblies. You haveme curious on this one so if you could give us a bit more info....

Hi,

All I've ever made are boats with the method I described above. I know that once you get the sponsons frammed up on the sponson main you can pop it off the jig and it's a lot easier to add the glueing strips for the chines, recovery pads and decking. Once the sponsons are attached to the main jig and the engine mains, nose block, afterplane framing and sheeting, the deck is sheeted and the whole thing is rigid I take it off the jig and then sheet the sponsons chines and recovery pads, everthing except for the running surfaces. Once I figure out what the angle of attack I want on the sponson running surfaces (for my boats I like about 3 degrees to start with) Then I add the gluing strips, block sand it and add the running surfaces.

Rocking the boat on the running surfaces on a glass top table or something equally level and then measuring the distance between the table top and the transom will give you a method of measurement to get you in the ballpark for angle of attack on the runninmg surfaces.

By the way none of the above was figured out by me. Thanks to John Logan and Russ Nachwiegh for taking the time to show me this stuff.

:blink:

What happens if you get more or less than the 3 degrees?

Too flat and the boat is too wet and stuck to the water with no speed and is a pig to drive. Too much and you have a blowover queen. It does vary from boat to boat. I've built 2 (supposedly) identical hulls using the same jig and the same patterns and they liked different angles.

 

[Hydro Junkie]

Griz, you really got lucky. Mike joining this thread is a serious bonus. I've seen his boats run and they are VERY quick. Now if we could just get the Brandt's in here, we could really start having some fun.

I was just thinking, talking about AOA. Mike is right about one boat liking one set up over another, but the boats I've seen are all 1/8 scales running the 3+ degree sponson runners. If you look at the E-R/C Unlimited boats, they use a 6+runner as a baseline. I also know that some of the guys running Vegas hulls have changed the AOA to improve the boat's speed and handling. What you can do is take an angle guage and see what the sponson inside has for a bottom AOA. If you replace all the framing as I suggested earlier, in option 3, you can pretty much set the runner to any angle you wish by raising or lowering the sponson transom bottom. If you go with a shallower AOA, like as in the 3 degree range, you could play with AOA's simply by changing the shape of ride pads on the sponson bottoms. I know the kit comes with a dihedral designed in. You could change that as well depending on the shape of the ride pads. You could also build the boat with no dihedral and play with the ride pads as well in that respect. I'm sure the others will chime in on this as well

 

[Grimracer]

The sponson angles are not to bad on that boat but the break distance on the roof is better for lower power motors.

The boat can run in the upper 40s as is.. That is with a lighter cowl.

Grim

 

[Hydro Junkie]

Grim, could you clarify what you are refering to on the "break distance on the roof"? Griz is a new builder and has no idea what you're talking about and I've rarely heard that one as well and am not quite sure what all is involved. Thanks

 

[griz2575]

You are right I have no clue what that means :huh:

 

[Grimracer]

Sorry.. forgot

the break is the place where the two bottom center section sheets come together. On the paynpak they are under the motor.

We found that this needed to be moved aft to better handle more powerful engines.

Do you underhand?

Grim

 

[Grimracer]

here is the bottom stock

 

[SayMikey]

Sorry.. forgot

the break is the place where the two bottom center section sheets come together. On the paynpak they are under the motor.

We found that this needed to be moved aft to better handle more powerful engines.

Do you underhand?

Grim

Nice cowl wonder where it came from........