Hard starting Yamato 102

[BillCNC]

I have been tossed to the side a little, ... But I just placed my right foot on a frame and pushed a little to get my body over the left rail, ... it worked great.

But then again, ... I'm not so sure about how that will still work siting back like I'm supposed to be. The next outing will be one for experimenting on throwing my weight around.

BTW, ... what is the turn radius on a race course?

Thanks
Bill

[Jack Stotts]

The turn radius varies widely and at some sites, it is dictated by the size and shape of the body of water on which the race is conducted. I've seen turns with a 300 ft diameter/150 radius on down. There is no set size or shape in the kneeldown business.except for record courses where the size is 3/4 or 1mile with the shape varying. Jack

[ZUL8TR]

trap

Here is what I was talking about,

As I sketched it for you, leave it flat in the left picture.

[johnsonm50]

The turn radius's I've seen are fairly similar but I've only raced several courses. What gets ya is how ruff it can be. You could run most turns flat out if they weren't churned up by a bunch of boats ahead. Even if your 1st around the next lap will be ruffer anyway.

[BillCNC]

Ok, ... for those more worried than I was, ... I sprang for a vest today. Whoo-Hoo!

It's coming from Lifeline and should be here possibly tomorrow or Monday.

Functioning Kill Switch, ... Always had one.
Helmet, ... Check
REAL life Jacket, ... Check

I now have my bases covered.

As far as the turns go, ... I just wanted to know what to work with and will work on them first, ... going straight, ... I think I can do that.

Bill

[fishinworm]

gee seems to me to be just a minor adjustment for starting it in the water try to open the idle jet a half turn more and dont use starting fluild that can score the cylinder wall then it will be worth nothing just try adjusting the engine in a barrel of water and with a prop off it this can help alot-- fishinworm

[BillCNC]

gee seems to me to be just a minor adjustment for starting it in the water try to open the idle jet a half turn more and dont use starting fluild that can score the cylinder wall then it will be worth nothing just try adjusting the engine in a barrel of water and with a prop off it this can help alot-- fishinworm

fishinworm,

Thank you, ... but that issue was taken care of. A longer pull cord and sitting forward was all that was needed.

[BillCNC]

ZUL8TR,

I have the "Air Trap" parts made, ... but I was wondering if I should first try sitting farther back before adding them, ... or will they be needed regardless?

Bill

[johnsonm50]

ZUL8TR,

I have the "Air Trap" parts made, ... but I was wondering if I should first try sitting farther back before adding them, ... or will they be needed regardless?

Bill

I don't think any hydro's that are being raced now go without. The lift gained is critical, the sponsons may never lift with most of the air escaping right behind them. There's also the possibility of too much lift but that can be addressed by trimming them down.

[ZUL8TR]

air traps

ZUL8TR,

I have the "Air Trap" parts made, ... but I was wondering if I should first try sitting farther back before adding them, ... or will they be needed regardless?

Bill

Add them you will find out that they are needed for the lift especially on your hull design. Use no glue just screws until tested as a I indicated on the sketch I sent you. You can always trim them to suit lift for the ride and secure them with glue and screws later. When I put them on my Wetback (Kelly's plans did not show full length traps) I did much testing and eventually trimmed them by not cutting them shorter but planing a concave (bottom up view) in them from sponson back to rear bottom to control air release. Found this to be better then cutting them shorter because it still left the vertical portion of the air trap full length to the rear to hook with in the turns. Finally glued and screwed them in place.

You will still need to sit back but be prepared to change your position as various running conditions change like going into the wind, going downwind and cross wind. In heat racing I was all over the cockpit to keep the boat trimmed for all the changing conditions. You will note that as your speed increases especially over 60 this is very important.

[BillCNC]

johnsonm50 & ZUL8TR, ...

It all sounds good, ... I want to put a couple of coats of epoxy to them first before they go on. The only thing is, ... I just hate the idea of just screwing them on temporarily. The thought of screwing them in and out for adjustment cuts leaves bare wood (screw holes) vulnerable to water contamination inside the holes and weakening of the chine log until the piece is finally glued on.

I do understand that it will be easier to remove then, join them together with double sided sticky tape and the adjustments all at once, but I think it would be simple enough to do them accurately and separately while being attached to the hull.

Would it be safe to say that because it's of a shovel nose design, it's probably going to have more lift than if it was of a more modern design?

If that's the case, ... is there a good possibility some of the trimming is already known from your past experience and could be done before permanently affixing them?

OR, am I just being to critical?

Thanks Guy's

Bill

[johnsonm50]

I worked alot on a Weback that a pal got as a kit from Clark craft. To clarify this kit is not all the best stuff, fir plywood being the worst of it. Its also heavy at 175. That said the 1st traps he put on were not enough so we did them over with more area. This made it better but its never been over 55 mph.
ZUL8ER has done much more & I'm confident will steer you right. All things being different tho there's no substitute for testing after experience is offered. Neither round or pickles are proven to be faster far as Ive read but pickles are less prone to blow over. You could seal the holes with clear shellac which would accept epoxy later or somthing like that for the bare wood concern.

[BillCNC]

johnsonm50,

I wasn't referring to shovels as being faster, ... just in having more lift. It seems that would be the reason the Pickle came to be, ... to eliminate unwanted lift.

Experimentation is always good and most of the time needed. Basically it's just a straight line from 1/4" below the sponson's to flush with the bottom of the hull at the transom. 3-1/16" high at the sponson's and 59-3/8" long.

I was just trying to find out if any mods to the basic design he sent me would already be know and could be immediately addressed now to eliminate unneeded trips for just testing the air trap. It's $50 for each trip just to get on the lake and not including travel expenses. $10 for the boat, $10 for the trailer and $30 for renting a chase boat for the first 2 hours.

Regards
Bill

[hydroid]

Turn fin?

1) This Spartan is a 10'(?) version of what I had as kid, the Tiny Titan 8', on which I cut my racing teeth and got hooked for a lifetime passion. The hull has almost no lift, flat compared to any 'racing' hydro, and as we've discovered, no air traps. These designs were Popular Mechanic weekend build boats, got thousands of kids on the water for endless hours of freedom. I'd be surprised (as would you) if you ever got enough lift to flip over. That said, keep testing, kicking out 1/8 at a time to get the sponsons up.
2) Watching vid where you're doing numerous left turns, I do NOT see telltale spray one would expect from a fin.....there should be some spray, I see nothing, indicating either you have not installed fin, or it's not down. That is why you are compelled to lean over strng wheel to plant left sponson edge to bite,...and still sliding. Pls confirm whether fin installed and down. If you had the fin down, you can extend reach shifting weigh back, raise front, even in turns. Maybe I'm wrong, pls confirm. I do not even see it installed in your pics.
3) I suggest you apply the fin, shift weight back before installing air traps, which might be eventuality, and tilt engine out a bit more to compensate for no lift.

This is a great community project!
Ps: my TT was also canary yellow, w 9.9 Merc, tilted and shimmed to the moon, thought I was coolest boat on the lake, a Yamato on 10' is cool!

[BillCNC]

1) This Spartan is a 10'(?) version of what I had as kid, the Tiny Titan 8', on which I cut my racing teeth and got hooked for a lifetime passion. The hull has almost no lift, flat compared to any 'racing' hydro, and as we've discovered, no air traps. These designs were Popular Mechanic weekend build boats, got thousands of kids on the water for endless hours of freedom. I'd be surprised (as would you) if you ever got enough lift to flip over. That said, keep testing, kicking out 1/8 at a time to get the sponsons up.

Hi hybroid,

Yes, it's a 10'2" big brother to the Tiny Titan. Kicking out proved to not be the answer, ... it resulted in taking forever to get it up on plane. Hence, ... adding the air trap.

2) Watching vid where you're doing numerous left turns, I do NOT see telltale spray one would expect from a fin.....there should be some spray, I see nothing, indicating either you have not installed fin, or it's not down. That is why you are compelled to lean over strng wheel to plant left sponson edge to bite,...and still sliding. Pls confirm whether fin installed and down. If you had the fin down, you can extend reach shifting weigh back, raise front, even in turns. Maybe I'm wrong, pls confirm. I do not even see it installed in your pics.

A Lee Tietze fin is on, ... and down. In fact, I wonder if I have to much fin hanging down, 6.5" below the sponson. I guess I could rais it up to the next hole, but that wont allow it to kick up if I hit something. I also could machine it down if needed.

A couple of reasons to why I am leaning on the wheel. 1st It's the pivot point and 2nd, ... I didn't know any better until I was just recently told I am sitting to far forward.

3) I suggest you apply the fin, shift weight back before installing air traps, which might be eventuality, and tilt engine out a bit more to compensate for no lift.

This is a great community project!
Ps: my TT was also canary yellow, w 9.9 Merc, tilted and shimmed to the moon, thought I was coolest boat on the lake, a Yamato on 10' is cool!

I was wondering if I should hold off on installing the air trap until I tested it with me kneeling in the correct position, but as you and others have noted, ... this design doesn't have much lift if any at all and it the reason for adding the air trap.

As far as the yellow, ... It's a lake racer and I wanted to be as visible as possible considering how small the boat is.

Thanks
Bill