Announcement

Collapse

Forum rules and expectations

Hello, and welcome to the forums at the Nautilus Drydocks, formerly Sub-driver.com!

We welcome anyone with a passion for submarines and a desire to learn and share knowledge about this fascinating hobby. Use of these forums indicates your intention to abide by our code of conduct:


1. No spam. All automated messages, advertisements, and links to competitor websites will be deleted immediately.

2. Please post in relevant sub-forums only. Messages posted in the wrong topic area will be removed and placed in the correct sub-forum by moderators.

3. Respect other users. No flaming or abusing fellow forum members. Users who continue to post inflammatory, abusive comments will be deleted from the forum after or without a warning.

4. No threats or harassment of other users will be tolerated. Any instance of threatening or harassing behavior is grounds for deletion from the forums.

5. No profanity or pornography is allowed. Posts containing adult material will be deleted.

6. No re-posting of copyrighted materials or other illegal content is allowed. Any posts containing illegal content or copyrighted materials will be deleted.
See more
See less

Aeromarine Sprint Cat 21

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Aeromarine Sprint Cat 21

    This is a Catermaran of the offshore style. It is powered by a K&B .21(3.5cc) of the inboard type. It is started by the use of a belt to your portable starter motor that you hook up to a battery that you carry with you.
    Click image for larger version

Name:	POUR9-00d8605791c086f1f153ea4ac3bcb567.jpg
Views:	1
Size:	45.6 KB
ID:	99967
    This boat was actually designed for a 3.5cc motor so it behaves very predictably so that you could win races with it.
    Click image for larger version

Name:	isxe0-00d8605791c086f1f153ea4ac3bcb567.jpg
Views:	1
Size:	77.2 KB
ID:	99966
    Last edited by greenman407; 01-27-2012, 01:20 PM.
    IT TAKES GREAT INTELLIGENCE TO FAKE SUCH STUPIDITY!

  • #2
    An inboard has the advantages of having less drag in the water as there is no lower unit when compared to a outboard. What you have is a rudder which you sharpen to a knife edge and a stuffing box(brass tube with a teflon liner) that exits the bottom of the boat just behind the engine. Through it you run your flexable drive shaft to an adjustable skeg that holds your propshaft. Much less drag. However a Outboard has the advantage of everything in one package that you just hang off the back of the boat(simplicity). You do not have an ignition system on these engines, thats why they call it a glow engine. You have a glow plug that has an element of platinum that you heat by the use of a glow igniter(1.2 to 1.5 volt battery). It will glow orange hot. This is done at startup. Once the engine is running you remove the battery conn. and the heat of combustion keeps the platinum coil glowing and thus keeps igniting alchohol. It would not work if the element was made of anything else. Alchohol is a funny fuel but relatively safe when compared to gasoline. In fact these engines will not run on gasoline at all. They are referred to as ABC engines(aluminum, bronze and chrome) for their alluminum block and piston with no piston ring(the piston is tappered), and chrome plated piston liner. They are also 2 cycle engines as you probably guess and with a short stroke crankshaft , they develop rotational speeds as high as 25,000 R.P.M. Cool aint it!!
    Last edited by greenman407; 04-23-2010, 02:06 PM.
    IT TAKES GREAT INTELLIGENCE TO FAKE SUCH STUPIDITY!

    Comment


    • #3
      Click image for larger version

Name:	4-26-10 boats, oscar 074.jpg
Views:	2
Size:	85.3 KB
ID:	58664
      Took the liberty of revealing a little more about this boat.
      Click image for larger version

Name:	4-26-10 boats, oscar 073.jpg
Views:	1
Size:	85.3 KB
ID:	58663
      The bottom shape of this catermaran is the subject of these pictures.It is a very shallow tunnel design and almost no deadrise on the canoes. The screw heads that you see on the back face of the sponsons is for water drainage of the bilge after each run. It also has a feature that has become very popular in recent years.
      Click image for larger version

Name:	4-26-10 boats, oscar 075.jpg
Views:	1
Size:	80.2 KB
ID:	58665
      These reliefs cut into the bottoms of the sponsons aid in reducing drag by aerating the
      Click image for larger version

Name:	flash drive 4 112.jpg
Views:	1
Size:	90.0 KB
ID:	58667
      area and by effectively reducing the amount of hull touching the water. The same thing can be seen on full size race boats:
      Click image for larger version

Name:	flash drive 4 223.jpg
Views:	1
Size:	93.2 KB
ID:	58666
      COOL HUH!!!
      Last edited by greenman407; 01-27-2012, 01:21 PM.
      IT TAKES GREAT INTELLIGENCE TO FAKE SUCH STUPIDITY!

      Comment


      • #4
        Click image for larger version

Name:	flash drive 4 115.jpg
Views:	1
Size:	91.1 KB
ID:	58678
        Click image for larger version

Name:	4-26-10 boats, oscar 074.jpg
Views:	2
Size:	85.3 KB
ID:	58677
        Yes I know, I know, one picture is a model boat from the back and the other is a full size boat from the front(dont have a picture from the back). The point I am trying to make is about speed brought about by the reduction of drag. In the picture of the black model boat , notice the bottom of the sponsons. They are flat, opening up this boat to the penalty of increased drag because the more surface area of the hull touching the water the more resistance to movement. The yellow full size boat has a sharp deadrise on its bottom which means at speed you have less hull touching the water. Actually on the stern of this boat it is not that steap but it certainly is not flat either. Which brings us to another point and that is, not all races are won on the straights( unless the straight is long). Some boat hulls are a compromise to allow superior turning capability and sacrifice some on the straights. In my experience , I have never seen a course that the turning performance can be enough to offset the advantage of having the superior straightway speed. This black boat could have been made faster by adding a high deadrise sponson. That is my fearless forcast for the day.
        Last edited by greenman407; 01-27-2012, 01:22 PM.
        IT TAKES GREAT INTELLIGENCE TO FAKE SUCH STUPIDITY!

        Comment


        • #5
          Click image for larger version

Name:	flash drive 4 120.jpg
Views:	1
Size:	90.6 KB
ID:	58765
          Click image for larger version

Name:	flash drive 4 124.jpg
Views:	1
Size:	91.2 KB
ID:	58764
          Here is some more shots of full size boat hull details. In the one on the right you can see its deadrise angle. In the one on the left, we have a good view of the sponson and strake reliefs.
          Last edited by greenman407; 01-27-2012, 01:22 PM.
          IT TAKES GREAT INTELLIGENCE TO FAKE SUCH STUPIDITY!

          Comment


          • #6
            I removed the 3.5cc engine and pipe and mount and put it up for sale on Ebay. Then I purchased this .46 inboard as its replacement. Coming soon to a theatre near you.
            IT TAKES GREAT INTELLIGENCE TO FAKE SUCH STUPIDITY!

            Comment


            • #7
              Oh dear God, a motor that is TWICE the size of the original. What could go wrong?

              Comment


              • #8
                Very observant Hardrock. Thanks for looking. Actually the Aeromarine hull is advertised as a 20/40 sized Cat. I know I didnt mention it in the thread but Ive had a .45 in it before. Ive had this boat since 1994. Trust me, itll do well. As allways, when driving something that has excess power, you have to take it easy in the turns and let er rip on the straights , then slow down somewhat in the turns. Soon you will learn the boats limitations. As you get some seat time and learn to read the water you can squeeze every bit of performance out of her, run er on the ragged edge. Back off before the flip. Its a different kinda boating.
                IT TAKES GREAT INTELLIGENCE TO FAKE SUCH STUPIDITY!

                Comment


                • #9
                  So, the past couple of days Ive also been spending time on this boat. I ordered and received a set of rubber dampened motor mounts from Speedmaster. With all the supplied stuff you configure the mount for the size rails you have in your boat as well as engine size. Once that was done , since the stuffing box and shaft were already in place I could slide the engine onto the shaft and have a good starting point as to where the mounts would go. I then marked there location with a pencil and started the installation process. Once they were attached to the rails, I then put the engine on top of it and marked thru the engine mount holes for the screw location.
                  Then it was a matter of drilling and Tapping for the hold down screws. Once the engine was in place, I could start trimming the upper hull for clearance of the engine ,as it would need to stick up thru. It came out pretty well. Then I cut the engine exhaust header to the proper length, and there you go.
                  IT TAKES GREAT INTELLIGENCE TO FAKE SUCH STUPIDITY!

                  Comment


                  • #10
                    Since my last posting.........its pretty much done. Im waiting for a couple of brass 90 degree elbows for the water cooling system to finish it up. In the meantime I figured that we needed to dress up the outside too somewhat. How about this?
                    IT TAKES GREAT INTELLIGENCE TO FAKE SUCH STUPIDITY!

                    Comment


                    • #11
                      Ive been searching and searching for 90 degree brass elbows. They are few and far between in the small sizes that I needed. Finally got a hold of some. Since I was using them on the water cooling circuit on this boat, this project has been on hold. Now that they are here I took the opportunity today to drill and tap for the 5mm x .8 elbow and install.
                      Last edited by greenman407; 01-01-2016, 11:40 PM.
                      IT TAKES GREAT INTELLIGENCE TO FAKE SUCH STUPIDITY!

                      Comment


                      • #12
                        Yesterday, I started her up. Being a brand new motor, the piston wants to stick at the top of the cylinder. Following the recommendation of the product Rep. stateside, I used a heat shrink gun and heated up the cyl. before starting. This is a different carburater than on the 75 outboard and the needle settings are completely different. Therefore, since I didnt know that I was trying to start it with the needle set wayyyyyyyyyy tooooooo rich. These engines come with no instructions or recommendations. When it spun over I had fuel blowing out of the carburator. When I closed the needle about a turn, she started right up. I ran a tank of fuel thru it(14 oz) I think its ready for the Big time. I just gotta find a time slot for it.
                        IT TAKES GREAT INTELLIGENCE TO FAKE SUCH STUPIDITY!

                        Comment

                        Working...
                        X