Todays Boating

[Colin BishopModerator @colinbishop34627]

Given the state of the Navy, they may have to recommission HMS M33!

Colin

[ashley needhamParticipant @ashleyneedham69188]

Working on the skidboat. Making the hull has been very easy now I have the plans and don’t have to think about the shape.

Builders insulation covered in epoxy/glass cloth. I now have to sort out what voids need to be carved out of the shell to accommodate battery, esc and Rx. Also, will the battery need to go fore, or aft for correct trim where running? Once the bottom is on, it will be difficult to carve out extra space at the stern. Perhaps I will hollow this out as an option, but not breach the well walls.

Would be nice to have a vintage style brass ball/ socket coupling in 3.17mm by m4 but not found anything. Have ordered a plated steel one as more vintage than the plastic types. Waiting on this before ordering the propshaft.

 

just ordered epoxy glue, in 250ml bottles (duribond) and disposable brushed AND hobby bandsaw blades from Tilear, a great supplier.

Ashley

[ashley needhamParticipant @ashleyneedham69188]

Stuff has arrived. More fibreglassing this afternoon. Hull is ridiculously light.

Ashley

[ashley needhamParticipant @ashleyneedham69188]

…and even lighter now I have carved out spaces for batt esc and rx! Servo mount has been made and in a minute I will be trying the git of the rudder wire guide tubes, wire and servo to see if any adjustment is needed.

Hopefully Mr Pat will deliver the propshaft and lovely two bladed brass prop today. A bit expensive the prop, but a Ranoesh sickle shaped one. 45mm…should look good sticking out the stern.

Several nautical books to get rid of. Will post pictures. Ashley

[ashley needhamParticipant @ashleyneedham69188]

Mr Pat has delivered. The Raboesh 45mm sickle shaped two blade brass prop is awesome!

As I am up in town drinking (obv in moderation…) with my ex works colls tomorrow. Planning to go to the 4D model shop first to get styrofoam 5 and 10mm sheets, and some other bits.

Tubes, Wires and servo positions all good.

Ashley

[Richard SimpsonParticipant @richardsimpson88330]

Definitely go to the shop before drinking as you never know what you might come out of the shop with if you go afterwards!

[ashley needhamParticipant @ashleyneedham69188]

The shop is packed full of the most delicious produce. You name it. They have it. Fantastic shop, but a tenner away ( on the train) for just a visit makes it expensive unless, like today, you have another reason to go there.

Ashley

[ashley needham]

On ashley needham Said:

The Raboesh 45mm sickle shaped two blade brass prop is awesome!

 

When you say ‘sickle’ shaped I take it you mean highly skewed!?  🙂

 

[ashley needhamParticipant @ashleyneedham69188]

Oh yes. Skewed indeed!

Spent a mere £71 in the shop. Egery isle you go go down…ooh yes..one of those…ooh yes a pack of this….ooh yes….its just packed full of  good stuff.

Styrofoam v expensive. Bought some white stuff at a lower density ( 33gm/ sq m rather that 52gm/ sq m) as it was about 1/4 the price, but looks like it will do the job.

Ashley

[ashley needhamParticipant @ashleyneedham69188]

The p&o ferry appears to ve eating batteries with its Graupner speed 600 ECO motor, even just pootling about. So have swapped it for a cooking 500. The new Quikrun esc is silent and much better for it.

Filling and wetndrying Skidboat hull. Always the slow process especially as the temperature has dropped. Second fill and one light coat of grey primer on, will make it look like I have not bothered to sand it all I dare say….

34mm od fibre washers purchased.

Ashley

[ashley needhamParticipant @ashleyneedham69188]

Skidboat top looks ok, but the foam planing step wedges are a bit messy. Currently the epoxy resin is drying, and once that goes off I can use a bit of P38 filler and sharpen the edges up a bit and give them a quick spray to see what else needs doing.  It is of course underneath so I am not quite so worried about perfection down there.

Rudder skegs on. Might get around to fitting propshaft tomorrow and then I will have to decide on the coupling ( sort of needs to look vintage, I.e not the usual plastic u/j).

Bought some thick wall silicone tube in black which I am hoping will look vintage-y with round (not hexagonal) brass splined ends, or at least that’s the current idea. 9 hour epoxy so can’t do much until tomorrow morning other than admire my super skewed brass prop!

Ashley

[ashley needhamParticipant @ashleyneedham69188]

No boating today as have bit of a sniff going on.. shame as I have changed the juicy speed 600 for a 500 in the p&o ferry and wanted to test it.

Third tranch of filling on the Veron, but it’s looking much tidier underneath because of it.

Ashley. Sniff sniff

[geconParticipant @gecon]

Lemsip ASAP laddie. And kleenex while you wait for it to filter through. Get well soon,

George

[ashley needhamParticipant @ashleyneedham69188]

Cheers George.  Been in the garden in the sun(!) Painting and so on.

Ashley

[ashley needhamParticipant @ashleyneedham69188]

Skid boat tested Sunday and Tuesday. Not good. Poor steering but more importantly, huge cavitation, and that even on smallish throttle openings.  Tried an X55 and it was quite quick but it didn’t cut through the cavitation. Tried rear weights to no avail. Tried x35 prop and still no good.

Flooded the boat Tuesday and killed the reciever….but still cavitated despite having halved the rear step height.

Several fixes to try on Sunday.

Thought about a call out to see if anyone had one but their experience won’t help. There was no steering on the original, and I imagine you chucked it in with the engine doing 22,000 rpm and off it went. Would the original have cavitation? I don’t want this to turn out like the Larsen .

Ultimately the bottom could be cut off and a new conventional speedboat sort of underneath made but I would like to keep the original bottom. Albeit tweaked a bit.

The prop hangs out the back like a surface piercer but it’s not…it is underwater. And the angle is steeper than I would normally use…it this the issue,?

So many questions. So little time.

Ashley

[ashley needhamParticipant @ashleyneedham69188]

Having bought some mfa 540/1 motors, i find that I have one in the box hiding. It had a metal flux increasing tube on it marked “555” and I didn’t check exactly what was underneath. Swapped out the m500 on the ferry. Test Sunday.

Bits for modifying the Skid boat made and stuck in place. Fingers crossed at least one of them i.privrs things.

Ashley

[Richard SimpsonParticipant @richardsimpson88330]

Just thoughts Ashley, which may be of use but you’ve probably already been through.  Cavitation can be down to the prop spinning too fast, the pitch being too shallow or flow through the prop being restricted.  I usually find that modellers get the idea of reducing speed or increasing pitch or frequently a bit of both, but also many have not realised how flow through the prop is being compromised in some way.  I have seen flat transom sterns with a prop sticking out of it and a modeller wondering why it won’t move no matter what combination of prop, motor and battery has been tried.

Are you sure you have a nice free path for water to flow through the prop and out the other side?

As I said just thoughts that may be of use.

[ashley needhamParticipant @ashleyneedham69188]

Hi Richard. The design has the end of the propshaft flush with the transom. What we don’t like is the second step being 2/3 the way down the boat length…it seems a bit near to the back and what with the front step, May be allowing air in.

Cavitation starts at very modest throttle openings. And is not over revving on a 1400Kv motor/ 8v lipo at these throttle openings.

See snap. I am going to try a transom flap to cover the prop, an extension to the front step to move it back a bit (mostly to increase bouyancy), and simply moving the battery to the rear to sink the rear end more. I actually put the prop 6mm deeper than plan to counter this very thing….

The rear step has been reduced already to about 10mm. I have a couple of hydro props to try ?

Ashley

[ashley needhamParticipant @ashleyneedham69188]

<p style=”text-align: left;”>Richard could you email me plse. I have a book you might like but your address on yahoo was unrecognised and can’t work out on the phone how to.pm you! Ashley</p>

[ashley needhamParticipant @ashleyneedham69188]

On a vaguely nautical note, the dance for our Hersham Ballroom dance group has a nautical flavour as its entitled ”  cruise ship dance” ..captain s black tie dinner.

To decorate tye hall I have had printed some portholes to go down the side of the hall, and am making life rings and a large ships wheel silhouette to go on the stage. For the table. I have made some ‘art deco’ ships, about9 inches tall, decorated same either side…6 of them, a bit fiddly painting them all. Shown on a shelf with a cheap hms victory!

What you get up to when you are retired!! Also have a Vic Smeed book, circa 1968 to out. It’s yours for postage.

Ashley

[ashley needhamParticipant @ashleyneedham69188]

Ok. The issue with the Skidboat cavitation is lift at the rear end. As soon as any meaningful throttle is applied, you can see the stern lift by probably 10mm, and it starts gurgling. I cut away the centre of the rear shelf but to no avail.

It is a combination of the propshaft having a fairly down angle, and the balance of the boat. There is no weight at the stern even with the battery taped on top over the rear deck, combined with the very large step 1/3 the way back from the bow giving a sort of pivoting action????

I plan to remove the rear step and skin the bottom with 10mm foam, from the rear of the front step to overhanging the stern. This can be taped in place for experimental purposes.

More drastic action will have to mean repositioning the shaft at a shallower angle, or before that, reprofiling the front step.

Ashley

[ashley needhamParticipant @ashleyneedham69188]

Ok, removing rear step….no good. Sheeting over bottom with 10mm foam and 40mm overhang…no good.

However what was evident when we looked really really had…was a little whirlpool forming over the prop and this is dragging air down. As the shelf didn’t cure this, I am fitting a shorter propshaft so the prop is an inch forward of the stern. I have cut ALL the foam off and once the shaft is in, make three different shaped forward steps to try out.

Low power 540/1 mfa motor great in ferry. Doesn’t quite get fast enough to cavitate now, but the two props still give it good acceleration.

Today…HSS, Hobbies Hydro and lander ferry. I seem to have three ferries now! P&o, hss and lander.

Ashley

[Richard SimpsonParticipant @richardsimpson88330]

Sounds like progress Ashley.  Props invariably end up as much trial and error as anything.

[ashley needhamParticipant @ashleyneedham69188]

I now have a shorter propshaft and have cut down the skeg so eventually the prop will be an inch forward of the transom.

Assuming this cures the cavitation it will be then just be a matter of finding the correct forward underwater shape, hopefully something similar to the original so as to be as close to the plan as possible.

The next project has been identified and items procured for it, but a lot of it hinges on getting a good figure to pilot it. It’s apparent scale depends on the figure and to an extent the size of the boat, but I need to have the fake V8 motor cover first to see how big this is in relation to any figure that will sit next to it….

Ashley

[Fred Ellis 1Participant @fredellis1]

Ashley in your post 19th Oct you have a copy of Boat Modelling  on your desk, as it happens I also have a copy on my desk, the only difference is your’s is 5/- and mine is 40p

[Author]

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