Topic: Springer Tugs (Read 1393894 times)

boatmadman · « **Reply #625 on:** October 05, 2007, 08:16:00 pm »

Here is my solution to a fixed kort on the springer.

Used a brass bar along the skeg soldered to the nozzle. Then I drilled the top of the nozzle and soldered in a spindle which then slides into a tube set in the hull. This allows me to remove the nozzle if required, and also allows me to modify to a steering nozzle if I wish to.

The prop and nozzle were supplied from G Sitek, the rest is my own work - you can tell that cant you!!

Ian

Arrow5 · « **Reply #626 on:** October 06, 2007, 02:43:51 pm »

Impressive hardware Ian, just a couple of points though , from a novice. I`m sure that the wide end of the Kort should be at the front and tapered end should be at the rear. The clearance of the prop and nozzle should be a minimum. Looks like you have quite a gap, does Sitek not recommend matched prop dia and matching nozzle ? Another tweak I see on some Springers is the relieving of the skeg with a 3 shape on the trailing edge, the propshaft coming out of the centre point of the 3. A few have minimal skegs and use A-frames to support the aft end of the shaft. I presume this is to reduce side area to aid tight turns. Martin; have you considered something similar plus a full square 2" rudder with fishtail or a T ?

boatmadman · « **Reply #627 on:** October 06, 2007, 04:37:00 pm »

I asked sitek about the orientation of the nozzle, and this is how they said it should be. The inner diameter is constant through the nozzle to about 5mm from exit end when it opens slightly.

The prop to nozzle clearance is less than it looks in the pic, its a bit deceptive really. The pic was taken when it was dry fitted and not properly aligned, now its fixed, the clearance is better

toesupwa · « **Reply #628 on:** October 08, 2007, 04:20:51 pm »

Quote from: boatmadman on October 06, 2007, 04:37:00 pm

I asked sitek about the orientation of the nozzle, and this is how they said it should be. The inner diameter is constant through the nozzle to about 5mm from exit end when it opens slightly.

The 'normal' way a kort works is to have the wider end in to the water flow, the prop, then a slightly reduced rear end..
This way it works almost like a jet engine.. the water entering the kort is 'pressurised' and then forced from the rear of the kort at a slightly higher pressure than the water surrounding the rear of the kort..
The 'outer' shape of the kort should be thicker at the fromt and tapered towards the rear..
Imagine the shape (in a cross section through the kort) to be almost like an aerofoil section, leading edge towards the water flow.

It sounds from your description Boatmadman as if the wider opening is at the rear of the kort?...

boatmadman · « **Reply #629 on:** October 08, 2007, 05:00:41 pm »

yes it is, and I was somewhat surprised by Siteks instruction, however, its made up now! To be honest, I am not sure it would make a great deal of difference at this size!

After all, its how you use it that matters!

Ian

HS93 (RIP) · « **Reply #630 on:** October 08, 2007, 05:06:00 pm »

A bit of full size info.

Peter

http://www.harringtonmarine.com/stdnozzleshapes.htm

boatmadman · « **Reply #631 on:** October 08, 2007, 05:28:24 pm »

Ok, I stand corrected - its backwards!

Next job, de solder and refit - unless I run the springer backwards all the time

Ian

Swordfish · « **Reply #632 on:** October 08, 2007, 07:00:41 pm »

Some time ago I ran across the Springer hull design on a US webstite and it was about the time I decided I needed a compact model that was easy to take to the pond. Soon after, a small towboat with an elevated pilot house caught my attention and my UNSTABLE MABEL became the result. ( She only looks unstable.) The model was scratch built with items on hand including an old 6 v. Dumas motor. For simplicity I installed it direct drive with a low pitch home made prop. Only then did I "discover" all the Springer competitive activity on MBM. In the meantime, I've simply used MABEL for play , most recently adding a barge load of kitty litter masquerading as coal. ( photo attached . . . . I hope :) )

The wonderful detail photos from Bunkerbarge inspire me to go back and add further detail. Many thanks Bunkerbarge

Tugboat Andy · « **Reply #633 on:** October 09, 2007, 04:43:47 am »

For maximum maneuverability the steerable kort installed similar to Scoot, Mustang Sally, or my boat is probably the way to go. The trade off for using fixed nozzle is the ability to accurately fit the prop tightly in the nozzle potentially increasing efficiency.

My understanding of the rule book is that competition boats are not allowed to use kort nozzles. My boat has a keel a bit longer than Scoot's and the wheel is smaller diameter so I am not able to achieve the same level of maneuverability....yet. In addition, my rudder is close to the waterline and if I apply too much power in reverse, the wheel is able to move enough water to actually make a little whirlpool and sucks air down the rudder cavitating the prop. I dare not operate in shallow water as small pebbles are easily sucked through the nozzle. It sounds like ice in a blender when this happens.

Best regards to all!

Tugboat Andy

Arrow5 · « **Reply #634 on:** October 13, 2007, 06:55:23 pm »

"ice in a blender" Ouch

Testing "Springberry" in rough conditions today,turn sound off and watch full throttle wave bashing on http://media.putfile.com/Springer-Coastguard-model-in-rough-water

boatmadman · « **Reply #635 on:** October 13, 2007, 07:28:05 pm »

Seasick !

Bee · « **Reply #636 on:** October 13, 2007, 09:20:48 pm »

I went to the Midlands Model Engineering show today.
Severa boat clubs represented although it isn't a boat show.
But not a single Springer on display :(

chingdevil · « **Reply #637 on:** October 14, 2007, 03:49:32 pm »

Come to the International Model Boat show in a couple of weeks time, I know of four that are going to be there Martins and mine.

Brian

djrobbo · « **Reply #638 on:** October 14, 2007, 07:32:19 pm »

Hi guys.......... well mark 1 springer nearly fiished......as soon as i can figure out how to put photo's on here i'll stick a couple on......

regards.....bob..

Tugboat Andy · « **Reply #639 on:** October 16, 2007, 02:26:08 am »

Quote from: arrow5 on October 13, 2007, 06:55:23 pm

Testing "Springberry" in rough conditions today,full throttle wave bashing

Hee hee hee....the boys thought that was pretty neat!

boatmadman · « **Reply #640 on:** October 16, 2007, 04:13:03 pm »

Some progress on my springer.

Stavros · « **Reply #641 on:** October 16, 2007, 06:58:38 pm »

three storey ,1st floor womens clothing 2nd mens clothing 3rd floor TOYS

Stavros

Arrow5 · « **Reply #642 on:** October 17, 2007, 10:08:11 am »

Quote from: Stavros on October 16, 2007, 06:58:38 pm

three storey ,1st floor womens clothing 2nd mens clothing 3rd floor TOYS

Stavros

So the die is cast Boatmad, Stavros has now given you a hint to the name of the latest addition to the Grace Brothers International Shipping and Towing Company fleet ! Whatsit gonna be, Capt Peacock, Mrs. Slocombe, Mr. Humphries, Mr Rumbold.

Nice build BTW.

anmo · « **Reply #643 on:** October 17, 2007, 10:39:17 am »

Quote from: arrow5 on October 17, 2007, 10:08:11 am

Quote from: Stavros on October 16, 2007, 06:58:38 pm
three storey ,1st floor womens clothing 2nd mens clothing 3rd floor TOYS

Stavros
So the die is cast Boatmad, Stavros has now given you a hint to the name of the latest addition to the Grace Brothers International Shipping and Towing Company fleet ! Whatsit gonna be, Capt Peacock, Mrs. Slocombe, Mr. Humphries, Mr Rumbold. Nice build BTW.

....and I name this ship 'Mrs Slocombe's Pussy'.

Arrow5 · « **Reply #644 on:** October 17, 2007, 02:45:23 pm »

...oh yeah I just wondered who would make reference to the lady`s cat >:(

Bridkid · « **Reply #645 on:** October 17, 2007, 05:54:37 pm »

"You've all done very well"

(Young Mr Grace)

Bridkid · « **Reply #646 on:** October 17, 2007, 06:00:07 pm »

Anyone out there going to the Blackpool show? There will be one or two Springer's on the Bridlington Club stand. I'm taking mine although she isn't finished yet.
See y'all there...................maybe,
Cheers,
Ian.

The long Build · « **Reply #647 on:** October 17, 2007, 08:27:38 pm »

Typical toys on the top floor ...

Boatmadman Will that not be a bit top heavy ??

boatmadman · « **Reply #648 on:** October 17, 2007, 08:55:16 pm »

Hope not! Its liteply skinned with styrene and no innards!

Stavros · « **Reply #649 on:** October 17, 2007, 10:02:24 pm »

Well it should have gone to the ground floor HABIDASHERY

Stavros

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Author Topic: Springer Tugs (Read 1393894 times)

Swordfish

Tugboat Andy

Bee

chingdevil

djrobbo

Tugboat Andy

Stavros

The long Build

Stavros