Re-Engineering A Dumas Pay'N Pak

[Hydro Junkie]

I found a 1/2X1-1/2X12" piece of 6061-T6 aluminum in the garage a bit ago. With a little bit of drilling and a whole lot of milling, it will make a nice pair of engine mounts. The fun part now is to get the final mount shape laid out on the block and then start making aluminum chips. I know the machinists in the forum love this kind of stuff. Any volunteers in the crowd

 

[Hydro Junkie]

Sorry for the long delay, between school and home maintenance, haven't had much time for working on the boats.

I've designed a set of engine mount mounting rails and started working on the first one. With my little Sherline mill, it tends to take time for any major part work so...............................................

One thing I have managed to get finished is shaving down the heads of the engine mount retaining screws that hold the rubber isolators to the bottom of the boat. When I originally set everything up, the heads stuck up from 1/16 to 1/8". Since I don't want the screws visible after the boat is painted, I broke out the Sherline Minilathe(first time this has happened and I've had the lathe for several years) and clamped an appropriately sized nut in the chuck. I ran the screws down into the nut and VERY SLOWLY cut down the height of the head. If there are any machinists that know of a better way to do this, PLEASE LET ME KNOW AS THE RESULTS WEREN'T AS GOOD AS I WAS HOPING FOR!!!!!!!!!!!!!!!

The next step will be securing the screws in the recessed holes with epoxy and resealing both inside and out of the bottom so I will be able to install the mounting rails and engine when the rails are completed. More to come

 

[RodneyPierce]

Sorry for the long delay, between school and home maintenance, haven't had much time for working on the boats.

I've designed a set of engine mount mounting rails and started working on the first one. With my little Sherline mill, it tends to take time for any major part work so...............................................

One thing I have managed to get finished is shaving down the heads of the engine mount retaining screws that hold the rubber isolators to the bottom of the boat. When I originally set everything up, the heads stuck up from 1/16 to 1/8". Since I don't want the screws visible after the boat is painted, I broke out the Sherline Minilathe(first time this has happened and I've had the lathe for several years) and clamped an appropriately sized nut in the chuck. I ran the screws down into the nut and VERY SLOWLY cut down the height of the head. If there are any machinists that know of a better way to do this, PLEASE LET ME KNOW AS THE RESULTS WEREN'T AS GOOD AS I WAS HOPING FOR!!!!!!!!!!!!!!!

The next step will be securing the screws in the recessed holes with epoxy and resealing both inside and out of the bottom so I will be able to install the mounting rails and engine when the rails are completed. More to come

HJ, next time take a brass sleeve, cut a slot in the side, and slide that over the threads of the bolt. Then tighten this entire thing up in the chuck. That will keep the bolt centered in the chuck, and much more parallel to your tool post then a nut chucked up will. Just make sure the brass sleeve is able to clamp tight on the bolt threads. This will also keep the chuck jaws from damaging the threads.

 

[big al]

I recently did the 40 version of that boat and it's a blast!

 

[big al]

more pics

 

[Hydro Junkie]

This weekend's progress was resealing the bottom, right nontrip and engine bay floor using West Systems epoxy. In the process, I installed and sealed in the engine mount retaining screws. I'll post more pictures when I get a little further along

Al, I remember seeing the thread, you did a nice job in the boat. I've built one from Roger's plans that I scaled down, still need to build a cowl for it. I figure it will be on the water next season, one of 5 or 6 that I need to get finished and on the water

 

[Hydro Junkie]

Due to schoolwork and a wife's reworking the kitchen, my total build progress for today was installing the rubber isolators and dropping the engine(still screwed to the old mounting plates) back into the boat to verify everything was still lined up. Finding all still fit, I'll be hitting the mill again tomorrow to continue the work on the engine mounts

 

[Kez]

HJ,

I noticed that you have the rudder and water pick up on the left. Have you tried this before? Would the water pick up (assuming it is a prop blast pickup) location supply enough water to the engine? I prefer prop blast pickup and a thin rudder. I have always mounted the pickup to the right thinking that as the blades come up, it would throw water up. It would be neater if I can mount it to the left with the rudder if I know it works.

kez

 

[Hydro Junkie]

In the case of this boat, I located the rudder to the left for two simple reasons:

1) Scale location

2) Ease of plumbing

The rudder has the integrated water pick up so it will have a constant flow due to "ram pressure". The only time the pressure should drop is in the turns as the water pick up is on the left side of the blade. Having the water line under the left deck also means that if I ever have a water line break, rather than sink the boat, it will only flood the left side since the discharge line is on the left side as well. I'm not a fan of the "prop blast pickup" as it's normally something that has to be messed with every time you pull the driveline or change a prop. They can also add drag, not something you want it a high performance boat

 

[’69 Dame]

This is a great thread- thanks for posting!

Marc

 

[Hydro Junkie]

Just a quick update on the engine mounts. It's taking forever to machine the first one since I've had problems with end mills slipping in the collet, kind of like a flex shaft. Anyway, here's how far I've gotten

 

[Hydro Junkie]

With school over for the quarter, if not longer, it's back to the boats. I'll be posting updates later this week

 

[Hydro Junkie]

Sorry it's been so long since the last update, too many other things getting in the way of working on the boats. I've finally finished the left side mount and have the right side down to final weight reduction trimming. After that, it's drill and tap the mounts, verify I can still get the starter belt around the flywheel and tweek the stuffing tube as needed. I'm including several pictures in this post. They will show the progression of the engine mounts from aluminum blocks to actual mounts(as far as I've gotten them anyway) and the engine's location now that I can fit it into the mounts. In pictures 3 and 4, I shot took the pictures showing the new mounts in relation to the engine and included the original plate mounts so you can see where I actually started

 

[Hydro Junkie]

I still need to thin the mounts down a bit so that the mounting lugs are thinner as well as tap for the engine bolts, but otherwise, here they are. If you have any thoughts on these, feel free to voice them

 

[Hydro Junkie]

Those last few pictures were really bad, weren't they? I have realigned the stuffing tube so here are some pictures of that, including a better look at the engine mounts

Also visible is how I openned up the radio box a bit so I can epoxy in higher sidewalls and a top to protect the radio gear since the cowl alone, as expected, didn't do the job

 

[Joe Wiebelhaus]

wow, I'm impressed, at this rate we wont need a update until fall of 2012, great job...............

I cut the grass today, the whole yard, at once, in the same day...............

 

[Hydro Junkie]

I can wait until November or December of 2012 for the next update as I have other hobbies and other things I need to work on besides this boat since I do have a life OTHER THAN BOATS

 

[Ken Smith]

Looks great HJ. Eagerly awaiting your build on the Dumas Circus. Those Jones sponsons will be sweet

 

[Hydro Junkie]

That one will be a remanufactured kit as well. That way I can use better materials in it and rework the sponsons framing all in one step. HOPEFULLY, others will like it as well

 

[Joe Wiebelhaus]

quit whining and finish/race something............