My Goblin

[Andy CParticipant @andyc56856]

Hi All

 

This is my first attempt at building a wooden one. The wood stock arrived yesterday (hence the question on storage). I have now cut out both the hull (2mm lite ply) and the bulkheads ((6mm Balsa).

 

Not particularly easy, as my knife skills are none existant, but got there in the end. The hulls are very nearly identical, but I think they shoould be OK.

 

More when I have it.

Andy

[Andy CParticipant @andyc56856]

first steps

[Bob Abell 2Participant @bobabell2]

Andy

 

How you`ve cut these out without a bandsaw, brings tears to my eyes!

 

If you nail both pieces of hull together, temporarily, while shaping, they would be identical!

 

Bob

[ashley needhamParticipant @ashleyneedham69188]

Using a bandsaw…the only way to go !! does this make you lazy though?

 

I find great difficulty in cutting something even as thin as 6mm balsa with a knife. Very difficult to get a good square edge, and the knife blade has to be dead sharp.

without squashing one corner or something.

 

Ashley

[Andy CParticipant @andyc56856]

A bandsaw, what a luxury. I don’t think that will be hitting my garage anytime soon. It is tough getting a good clean cut with a knife, especialy at the end of the cut. The ply was easy enough and I did try with a fine tooth tenon saw that I have and it was very ragged.

 

Should be able to add the front bulkhead and the transom today. The bow will be tough as I do not have ant clips with points in them, like a crocadile clip. Will have to use a load of elastic bands and see what happens.

[Tony BurtonParticipant @tonyburton83970]

HO HO HO

 

I wouldn`t consider cutting anything above 1mm with a knife……..I always use my trusty scroll saw

Tony

[Andy CParticipant @andyc56856]

Well Bow and Transom now in.

 

For a beginners boat, the bow is tough.

 

Andy

 

[Ian GardnerParticipant @iangardner62867]

I bought a small bandsaw for about a £100 years ago and it was the best thing I ever did. Now, if it can be cut on the bandsaw, it is! I also bought a cheap scroll saw (£30 or 40) and hardly ever use it- wish I’d spent a bit more on something decent.- still beats using a knife though.

 

Ian

[ashley needhamParticipant @ashleyneedham69188]

Machine mart do a 7 1/2 inch throat bandsaw for £120….I have one of these and a large DeWalt jobbie for cutting larger bits of wood.

 

The small bandsaw is perfectly adequate for most things barring long perfectly straight cuts, where I do find it wanders slightly following grain sometimes. However for the sorts of sizes we normally use this is not too much of an issue.

 

We had a thread a while ago on someone wanting to know of a small table circular saw for cutting thin planks up for a project, as it was agreed that this is the best tool for that sort of job..I think the Proxxon (not sure if spelt correctly) was just about the only one to consider for size and price. No good for curved cut of course.

 

Ashley

[Andy CParticipant @andyc56856]

Bow did not take, will have to retry. Using normal PVA, anything better out there to try????

 

Andy

[Bob Abell 2Participant @bobabell2]

Andy,

 

The current cold weather is probably preventing the PVA from setting properly…..ie….hopeless conditions in a cold garage!

Take it indoors?

 

I would recommend a filling block on the inside of the bow, to increase the joint area.

You could drill a few holes and use twisted wire as a clamping device?

 

Bob

[Bob Abell 2Participant @bobabell2]

Andy

 

Another tip

 

Your model needs to be anchored to the work bench and accurately lined up with a centreline and other guides to guarantee a nicely built hull

 

We don`t want to see a banana shape!

If my advice is not required, please let me know

 

Bob

[ashley needhamParticipant @ashleyneedham69188]

I have been using superglue lately for thing like bows…grabs and dries very quickly while you hold it (be careful here~!!!) and then you can fit a filler piece inside with araldite or PVA for strength after, as I wouldnt simply rely on the superglue.

 

OR use 5 min Epoxy…same thing, just have to hold on for 5 mins or so. As Bob says, needs anchoring down..and then you can have one or more tri-squares or something perfectly horizontal or vertical, and a centreline to line up the bow with whilst glueing.

 

Bob.. how can your advice NOT be required !!

 

Ashley

[Bob Abell 2Participant @bobabell2]

That`s very nice of you, Ashley…..Thank you

 

But there`s nothing worse than a cockeyed hull!

Centre lines, squares and handy chunks of steel are a must!

 

BTW………I`ve had some very bad reactions from superglues and epoxies lately and only use them when absolutely necessary….So just be aware

 

Bob

[Andy CParticipant @andyc56856]

Thanks guys. Bob, any advise is surely welcome. I will see what I can do on the centre line front. 2 inches of snow this morning and 1 degree out. Not good weather for standing in cold garage.

 

Andy

[Bob Abell 2Participant @bobabell2]

Come on, Andy

 

Let`s have a progress picture, please?…..Your hull setup if possible?

 

Bob

[Andy CParticipant @andyc56856]

Hi All

Finally managed to spend some time on the Goblin. I have fitted the bottom of the hull and added some strips of balsa to the topside to add strength and extra area for fitting the cabin later.

The keel has been fitted and notched ready to take the ballast bulb. Bought the bulb, rather than making my own. Not sure I am ready to start smelting lead and casting moulds yet.

Also had time to fit the rudder tube and install the rudder.

Next is to fit the prop-shaft and motor. due to the shallow nature of the hull bottom the prop-shaft has to be fitted through a slot about an inch long. Once fitted this slot will need to be filled and made water tight again. I had thought of using a wooden insert from the inside and then using filler on the outer side and smoothing off. Due you think this would work? Any other suggestions for prop-shaft sealing very welcome.

Andy

[ashley needhamParticipant @ashleyneedham69188]

Andy. I would just slap a bit of p38 filler around it.

PERSONALLY I would stick some 1/4 inch stringers around the hull joints inside, just as an extra…

Is the keel slotted or pegged through to the inside of the hull?? I would not be keen on relying on a simple glued joint outside to hold the keel on. Lots of bending moments going on down there.

Ashley

[Andy CParticipant @andyc56856]

HiAshley

I thought filler would work. I thought about the stringers, just very tricky to get in there. The keel is slotted and an interference fit with reinforcing strips vertically between the two middle bulk heads.It feel very secure.

[Andy CParticipant @andyc56856]

Hi All

A bit of advice needed with regards to the propshaft. I have had a look through all the other relevant posts about the grease etc, and I am quite happy about packing it out. My question though is about the amount of play in the shaft. I bought a ready made one by Graupner and there seems to be about 2mm or more play in the shaft with both end nut and washers in place.

Does this seem excessive?

Cheers Andy

[ashley needhamParticipant @ashleyneedham69188]

Andy, that is well excessive. My personal preferance it to make a pair of nylon washers (milk container etc) using a WAD PUNCH set (a set of punches that produces different sized holes) and have one inboard and one outboard, and then, having LIGHTLY greased the shaft, adjust the nuts so that there is virtually no play at all. A drop of oil now and then on the inboard end is all thats required for lubrication, water does the other end.

Do not ask about filling shafts with oil or grease. No one will agree. If the shaft is stainless its fit and forget as far as I am concerned.

It does seem that some shafts are made so that you cannot get minimum play.. I have used JP shafts for the last couple of boats and I have had to use additional washers, as the threaded portion stops well short of the tube.

Ashley

[Andy CParticipant @andyc56856]

Thanks Ashley

Looks like another tool to be added to the toolbox. I will see what I can find.

Also do I really need to solder capacitors on the motor?

Cheers

Andy

[Andy CParticipant @andyc56856]

Hi all

Update and pics of the Goblin. Now my exams have finished I have been able to spend a bit more time on it.

Electrics sorted, need to obtain a new battery though as the only one I have is a 7.4 LiPo and this is not compatable with the Mtroniks Mini Marine 10 amp. Thought about a 7.2 nimh, should do the trick.

Added some stringers to the inside of the hull and fitted the Mast holder. The mast holder is over size and will need to be chopped once I know how high the cabin sits. the actual mast will slide down inside the holder and will be secured. Deck coaming fitted also, ready for cabin to be built.

Also filled and rubbed down any pin holes and gaps.

I do however have a problem with the Propshaft exit. This has been secured in place with epoxy and seems to be resisting any attempt at sanding. Any ideas,? I don't want to get too rough as this might effect the rest of the hull ply.

Regards

Andy

[Andy CParticipant @andyc56856]

Another long overdue update.

I have been working on the cabin deck, sails and painting over the

last few weeks/months.

Cabin now completed and fits very well to the deck.

This the cabin fitted and the boat given a coat of Hemple marine underwater under coat.

I choose to use marine paint after reading through a lot of threads on painting and finishing.

If it is good enough for full size boats, should be ok for my little Goblin.

I put two very good coats on and followed it with a coat of Hemple two part gloss white,

this paint can be used as an undercost (odd for gloss, but that is what it says on the tin)

then a top coat can be added.

Then started to work on the sails, following the guide set out by Glynn.

Used an old umbrella to make the sails as it should catch the wind nicely.

Main sail fitted mast.

Not completely happy with the results as the tape looks out of place, so i

tried a different method with the foresail. I made it slightly over-size and used

Wonderweb to make a hem. worked really well and looks good too.

Now to see if the thing actually floats. Filled the bath with a lot of water to get

clearance on the keel, but to my complete amazement it actually does float.

A close up view of the sail adjustment ropes (well string and a button).

 

Just have to finish painting the blue above the water line and finish the RC install,

but should be able to try her on the lake at Bushey.

 

More next time.

 

Regards

Andy

Edited By Wraith Leader on 08/09/2012 09:33:23

Edited By Wraith Leader on 08/09/2012 09:34:19

Edited By Wraith Leader on 08/09/2012 09:34:51

Edited By Wraith Leader on 08/09/2012 09:35:56

[Andy CParticipant @andyc56856]

Long over due, but the Goblin had it's first outing on proper water today. We were spending the morning climbing and zip lining in Tilgate park down in Crawley. Tigate park also has a very large lake that is used by an adventure company for all sorts of boating, so I thought it would be a great place for first sea trials. Well, what can I say. The wind was up, so I thought it should sail nicely. She did!!!

I was amazed. There were some dead spots by the shore, under some trees where she became a bit stuck. No problem, crank up the motor and she was back in the wind. Battery was good, using a lipo at 7.2 v, so had a good sail about.

Second time out I decided to yighten the sails a bit and see if she would speed up. Really bad idea, she sailed out to the middle of the lake, and would not respond very well to the tiller. I really struggled to get her back, even using the motor, but she returned eventually. When lifted from the water i noticed why she struggled under electric power, the prop had fallen off. I had thought I had screwed it on tight enough, but obviously not.

Can anyone suggest a way of giving more rudder movement, maybe longer servo arms or something?

Also, what did I do wrong with the prop? It is is a M4 screw threaded item.

Any ideas appreciated.

regards Andy

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