OSA 1 Missile Boat

[Tim CooperParticipant @timcooper90034]

[Tim CooperParticipant @timcooper90034]

Made a start on an Eezebilt OSA 1 Missile Boat, whilst in lockdown and a change from gardening.

Tim

[Bob Abell 2Participant @bobabell2]

Is this a kit, Tim?

It looks quite large too

Bob

[Tim CooperParticipant @timcooper90034]

Bob

It's an Eezebilt plan printed off the website on my home printer. So cut the plan up to make templates.It's 32" long and I am using 3mm lite ply for the framework, then 2mm for the hull sides. Not decided what to use for the super structure.

If you put Eezebilt boats into Google you will see the website.

Tim

 

Edited By Tim Cooper on 07/04/2020 16:53:00

[Tim CooperParticipant @timcooper90034]

I have been looking at the prop tube needed for the OSA and it looks as though I may need a14" tube. Never having used one this long will it need to be supported along its length. Or should I try to find a way to use a shorter one?

Tim

[ashley needhamParticipant @ashleyneedham69188]

Tim. I personally wouldn’t use a 4mm shaft/tube at that length, a5mm one perhaps.

Could you use a shorter tube and have to ‘bare’ shaft inside, possibly supported with a bearing or even a bit of brass tube? This would effectively give you a centre bearing, and the tube does not need to extend inside for any length?

Ashley

[Colin BishopModerator @colinbishop34627]

Re Ashley's point above, Model Boat Bits allow you to mix and match shaft and tube lengths:

https://www.modelboatbits.com/PROP-SHAFTS/

Colin

[Tim CooperParticipant @timcooper90034]

Thanks Ashley / Colin

I wondered how you could buy different lengths of tube and shaft.

I will have a look at Model Boat Bits.

Tim

[Tim CooperParticipant @timcooper90034]

Ashley / Colin

Sorted what I need to order from Model Boat Bits. Thought I might as well get the appropriate support at the same time. Would an A frame support be better that a P support or is there not much to choose between them.

Tim

[Dave MilbournParticipant @davemilbourn48782]

Tim

An A-Frame is much better support than a P-bracket but at this size it's more a matter of appearance.

Dave M

[Ray Wood 3Participant @raywood3]

Hi Tim,

I'm guessing the central keel doesn't support the stern tube at all when it exits the bottom of the hull ?? It does seem to be a very long stern tube at 14" almost half the length of the boat it must be at very shallow angle.

The way round this is to extend the keel to form a skeg which also protects the propeller.

Regards Ray

[Tim CooperParticipant @timcooper90034]

Thanks

Ray, the angle is quite shallow, I can have a look at that. I was trying to avoid the problem I have just had with my S100 conversion. The tubes are long on that which gave me problems with noise at high revs especially with the outer motors , originally 380's, the central brushless wasn't so bad; after a change in flexible coupling.

Tim

[Tim CooperParticipant @timcooper90034]

Not much progress lately as been waiting for the propshaft and P bracket from Model Boat Bits. Arrived this morning, Steve told me he taking a little longer to keep up with orders at present. But I can now fit the shaft and bracket, then start the hull sides etc.

I managed to order two P brackets so I will just have to find another boat to build to use it! The lockdown must be getting to me as I managed to order two sets of figures for the OSA the other day. Airfix British Infantry Afghanistan 1/48 scale!

Tim

[ashley needhamParticipant @ashleyneedham69188]

Tim. That's a thought… the multi-pose 1/48 Airfix figures, and hard styrene will carve, glue and fill well.

Ashley

[Tim CooperParticipant @timcooper90034]

Well the crew has arrived. Unfortunately the accommodation isn't ready as the superstructure has developed major twists in the lite ply. Will have to scrap and start again.

Tim

[ashley needhamParticipant @ashleyneedham69188]

Just been using lite ply on the Swordfish. Ghastly stuff really. It has its uses as long as it includes being able to brace it well..

Ashley

AND it has a really strong grain which takes some major filling work.

[Dave MilbournParticipant @davemilbourn48782]

Amateurs all…….

DM

[Tim CooperParticipant @timcooper90034]

Yes, definitely amateur. 

It's 2mm lite ply that has warped as I waited to use it.

The superstructure is a narrow box 45mms wide and about 350 mms long. The bracing didn't keep it square. I have some 1/16th ply so will use that for the sides and front.

Tim

Edited By Tim Cooper on 07/05/2020 09:34:59

Edited By Tim Cooper on 07/05/2020 09:35:41

[Dave MilbournParticipant @davemilbourn48782]

Tim

A long, thin box structure isn't a good application for 2mm liteply. It would probably twist even if built from birch ply. I use it for sheeting where the area is supported all round by a framework e.g. the sides and bottom skins of a hull, interior cockpit sides. Store it laid flat in a dry place and sand it smooth all over before you use it. That will reap benefits when it comes to finishing it. You'll find that good-quality liteply has one side which is noticeably smoother than the other, too.

Ashley

It's not a pain; it's just a different technique. Apply a thin coat of fine-surface Polyfilla or similar all over the ply; allow it to dry then sand it off with 320 paper. It will magically have filled all the grain. Dust off thoroughly before finishing. I'll conceed that birch ply is easier if you just want to prime and paint the bare wood; liteply really requires some sort of covering medium e.g. tissue or glass-cloth. If it really was that "ghastly" then I wouldn't use the stuff; I can get birch ply from the same source for the same price….

Dave M

[ashley needhamParticipant @ashleyneedham69188]

DM. I don’t normally use the stuff. I used it for the Toyboata (big box, not fussed about the finish) just to see what it was like, the sides of the Cobb, as I thought it might be a bit lighter than 1.5mm ply I would normally use, and Swordfish….as I had some left!

Filling before using is a good idea if that is what you meant, and one that only a professional would think of 🏅and I will think on that if I ever use the stuff again which is unlikely.

Other materials I use already have a superior glossy, hard finish one side

Ashley

[Tim CooperParticipant @timcooper90034]

Dave

The 2mm was bought for the hull sheeting but the original used 1/16 balsa, so thought I would try the lite ply. It has been stored flat in the house but has still warped.

I will have to try the birch ply or 3 mm lite ply.

Tim

[Dave MilbournParticipant @davemilbourn48782]

Filling before using is a good idea if that is what you meant

Not quite, m'duck. If you fill it before you start to glue it then the glue won't work – or not very well if it does. I meant to sand the whole sheet smooth before you cut out any parts from it.

I shan't comment further on your last remark, except that we must agree to differ!

DM

[ashley needhamParticipant @ashleyneedham69188]

With you there DM, however for , for instance, the Crusader, filling before cutting would have worked fine as the only gluing took place on the rear face.

Obviously it depends on the application.

Ashley

[Tim CooperParticipant @timcooper90034]

 Progress has been made with skinning of the hull bottom. Still need to finish the bow area. Not sure if I can persuade the 2mm liteply to accept the curve at the front? I may order some balsa block for the bow, as used on Fairey Huntsman. Will fit the prop shaft and motor before starting the sides.

Tim

 

 

Edited By Tim Cooper on 15/05/2020 13:31:17

[Ray Wood 3Participant @raywood3]

Hi Tim,

Do you have sheet balsa you could laminate the bow blocks from, it would save you ordering some ??

The other disadvantage of the balsa framework is it will distort if you stress it when putting the bottom skin and you end up with a distorted deck line ??

Regards Ray

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