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Author Topic: PCF (Patrol Craft Fast) Vietnam Swift boat build  (Read 62804 times)

red181

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Re: PCF (Patrol Craft Fast) Vietnam Swift boat build
« Reply #50 on: February 26, 2015, 08:07:06 pm »

I was planning to do another water test today, but it was just too cold, too windy. So, spent some time tidying up. I now have a battery box, the esc's are positioned, I have two water outlets to look like exhausts, and all the water cooling is done. I had to change things about a bit as its a bit tight between the motors, so hopefully the cog is correct
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red181

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Re: PCF (Patrol Craft Fast) Vietnam Swift boat build
« Reply #51 on: February 26, 2015, 08:10:02 pm »

Deck is now on, and curing :-))
Next job to do the coaming and make sure the water stays out, there will be too much electrical gadgetry to get wet!
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red181

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Re: PCF (Patrol Craft Fast) Vietnam Swift boat build
« Reply #52 on: March 05, 2015, 12:04:51 am »

started with comings, and I decided I wanted the engine hatches to open like the real boat, then spent hours thinking how to do it, and create something that would stop water ingress..... still thinking!
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red181

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Re: PCF (Patrol Craft Fast) Vietnam Swift boat build
« Reply #53 on: March 05, 2015, 12:05:47 am »

don't want this to happen :o
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red181

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Re: PCF (Patrol Craft Fast) Vietnam Swift boat build
« Reply #54 on: April 06, 2015, 10:46:57 am »

its been in the water. some great success, and some not <:(

So, I tried the esc's and they appear to be fine. I ran the boat on two 3 cell 5000mah lipos, so one 3 cell per motor/esc. I didn't run that long, as I kept getting a loss of signal, which when back at the workshop was a bad servo lead extension. Motors where cold, so I increased the prop size from "x" 40 to "x" 45. The bigger props where much better, no onboard data logging, but the speed was visually better, and the motors didn't appear to be screaming.

COG  was way off with the batt packs sitting between the motors, the boat was up on the plane at a very slow speed, and looked a bit silly. In real life, this boat always looked a bit bow heavy, so I moved them forward and it sat in the water better. Water cooling worked, but the exit water from  the hull was no more than a dribble, disappointing as I wanted it to be more visible.

The big set back was the water entry into the boat. It seems to be coming from the stern, and I suspect its the rudder mounts. I've had it with the cheapo plastic things, so have ripped them out and will make my own, should have done that from the start >:-o

Now I need some  advice on mounting the rudders due to the slight "v" angle of the hull. Ill have to post this question fresh, as it seems nobody is commenting or posting anything in this thread other than me! :((   
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red181

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Re: PCF (Patrol Craft Fast) Vietnam Swift boat build
« Reply #55 on: April 06, 2015, 12:09:59 pm »

Hi Dave,

many thanks for replying over on the other fresh post. I'm a bit stupid here. I get the wooden block to set the tubes dead straight, great idea, and I had forgotten to make them a bit wider than the shafts, so thanks for that. So, if the block is on the bench, is the block being fitted into the hull, am I cutting a big hole in the hull :embarrassed: :embarrassed:?

The underneath of the hull is a bit of a mess now, and needs glassing , so how do I seal the underside of the tubes as they will not be flush to the hull, not explaining that very well am I, Ill take a pic and be back in a bit!  :embarrassed:
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imsinking

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Re: PCF (Patrol Craft Fast) Vietnam Swift boat build
« Reply #56 on: April 06, 2015, 12:29:14 pm »

re the rudder mounting not being square on , you need to knock up two tapered wedge's per each rudder one either side of the skin on both sides if it's twin rudder, the angles easy to work out just set the hull up on the stand and cut a cardboard template to match the hull bottom & there's your angle, the outboard wedges will need to be the minimum possible thickness & faired in to smooth waterflow , inboard ones not so critical thickness wise, the material used will need to be suitable for the hull wether its ABS or FIBREGLASS & glued into position, then drill the required holes, there's a LOT of pressure on rudders in a turn so it has to be secure, it always amazes me when folk just slap filler round a rudder post & expect it to remain leak free.
Bill
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red181

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Re: PCF (Patrol Craft Fast) Vietnam Swift boat build
« Reply #57 on: April 06, 2015, 01:17:00 pm »

here is the hull, bit of a mess, I've cleaned it up, inside and outside, Bill can you just explain the wedges again, I'm assuming I need to do Dave's block idea to drill from outside the hull into the blocks I fit on the inside to ensure they are straight, then will they need wedges on inside and outside of hull, when tapered, would the thick end of the taper not be on the outboard side to make the posts straight? I hate this sort of thing, and yes I agree, I don't do blobs of filler just hoping it will be secure and not leak.  :-))
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inertia

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Re: PCF (Patrol Craft Fast) Vietnam Swift boat build
« Reply #58 on: April 06, 2015, 01:57:39 pm »

Paul
Does this help explain? There's no reason why you shouldn't incorporate blocks inside the hull as well as the P40 fillet; you'd need to drill the holes exactly at 90° however. The other way would be to make the blocks to fit roughly, then slide them over the brass tubes on the inside to act as supports and P40 the lot to the hull.

Bill
The type of models I am talking about are Model Slipway's scale workboats, not very fast electric launches. The loads on the rudder are not very great (unless you hit something like a submerged brick!). Some of the Slipway models do have cast white-metal collars to support the joint between the hull and the rudder tube. I posted the drawing simply to prompt ideas, not to give a definitive method of doing the job. I know very well that my way isn't necessarily the best or the only way.
P40 is a pretty good medium for supporting rudder tubes, having chopped strand glass incorporated into it. It's not like P38, which is a filler and has little inherent strength.
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Perkasaman2

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Re: PCF (Patrol Craft Fast) Vietnam Swift boat build
« Reply #59 on: April 06, 2015, 02:22:21 pm »

Hi Red, your motors and water pickups appear to be mounted on blocks glued onto the hull floor. I would suggest that the rudders also need to be mounted likewise. Resin or glass a pair of blocks centred on the location of each rudder. Externally use masking tap to cover the previous holes. Having the deck in situ does make matters more fiddly but this is do-able. Block needs to be a around 1/4" - 3/8" thick. This will give lots of support to the rudders. When the blocks have set invert the hull and carefully drill out for the rudder tube holes carefully keeping vertical alignment throughout. Remove the exterior masking tape and tidy up the outer hull.

Dave's advice to offset the shafts from the prop's centreline is a very good idea. Props can be removed and the shafts can be withdrawn in the future without needing to unship and disturb the rudders.
Alternatively you could repair the damaged hull inside by using plastecine to cofferdam the damaged area and pool resin into the coffered area having first taped over the holes externally. later you could then bond in the mounting blocks as given above. I find the toughest part of any job is thinking through the best method, doing is usually far easier than anticipated.
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Perkasaman2

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Re: PCF (Patrol Craft Fast) Vietnam Swift boat build
« Reply #60 on: April 06, 2015, 02:25:13 pm »

Oops! Double posts. Dave has given an excellent diagram.
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red181

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Re: PCF (Patrol Craft Fast) Vietnam Swift boat build
« Reply #61 on: April 06, 2015, 05:28:16 pm »

Thanks chaps,

Dave, that's the picture I needed to see! :-)) I was making too much fuss about the outside of the hull, its all inside the hull where the work is, the picture tells the story,  not much room in there but it has to be done, so its tidy up the mess first, and make the jig :}

Be back soon!
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MadMax

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Re: PCF (Patrol Craft Fast) Vietnam Swift boat build
« Reply #62 on: April 06, 2015, 06:54:55 pm »

sell it to meeeeeeeeeeeeeeeeeeeeeeeeeeee
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Stavros

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Re: PCF (Patrol Craft Fast) Vietnam Swift boat build
« Reply #63 on: April 06, 2015, 08:00:22 pm »

WHY cant we see Dave's rudder pics
 
 
Dave
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imsinking

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Re: PCF (Patrol Craft Fast) Vietnam Swift boat build
« Reply #64 on: April 06, 2015, 08:05:48 pm »

 O0  WELL that's what was needed to get the thread going again ! Each has their own idea of which way to do a job , you do what your comfortable with . . . you dont have to hit a brick to wreck y'rudder, a plastic bag will do an admirable job too when it wraps around the prop , the modern rudder assemblies are usually cast nylon mounts with a flange on t'bottom & a thread to tighten down securely so they have to butt up sq. with something to be secure , the strand reinforced isopon sounds good for the outside and use it inside to build up a sq. face ? Being ex shipyard I tend to over engineer things , but I do what I want to do . . . . :P
Bill
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red181

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Re: PCF (Patrol Craft Fast) Vietnam Swift boat build
« Reply #65 on: April 06, 2015, 11:11:42 pm »

I've made a start, with wedges and the jig. When I was working with HS93 a couple of years ago, he was raving on about a gadget called a wixsey (I think). I paid little attention at the time, but recently it turned up in some bits and bobs I didn't sell for him. So I had a play with it today, and wonder how I have managed to survive with out it!

Using this little gadget, I was able to measure the angle inside the hull at 10 degrees, then made some wedges for inside the hull. Ive done a cardboard template for the jig, so the plan is wedges and blocks in the hull, pre drilled so I know the holes are straight vertical and true, epoxy them inside the hull, use the jig to position the rudder tubes, that I have to make from brass, turn over hull, pour resin in to fill all the nasty holes etc, and lock the rudder tubes in.

I want to try and make some sort of chamfered end in the tube for an o ring to sit in, hopefully these will not leak. If anybody knows a better way, shout up! Thanks to all comments, its nice to have a conversation going, and thanks to mods for merging the topics 
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inertia

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Re: PCF (Patrol Craft Fast) Vietnam Swift boat build
« Reply #66 on: April 06, 2015, 11:29:11 pm »

I've had so many problems with those moulded things that I've stopped using them for anything except a flat-bottomed hull. Usually the nut won't screw down the thread for more than a few millimetres and, as you say, if the face of the flange doesn't fit square with the bottom of the hull then no amount of compressing the O-ring will seal it. I don't particularly like the weird shape of the tiller arms or the way they are clamped onto the shafts. I prefer to make my own rudders, shafts and tubes from brass and use Raboesch or Robbe tillers with metal inserts and grub screws. I've found that P40 is very good for fitting brass prop tubes and bow thrusters into GRP hulls, too - but hey, that's just me.
Paul - just an addendum after seeing your post appear as I was about to Send mine; If the tops of the rudder tubes are above the waterline then it's unlikely you'll get any ingress at all - at least not that way! If you do then try fitting a short piece of silicon  tubing to "sleeve" the joint between tube and shaft.

Suit yourselves.  8)

DM
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Duncan PBR

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Re: PCF (Patrol Craft Fast) Vietnam Swift boat build
« Reply #67 on: April 07, 2015, 08:07:02 pm »

Hi Red 181.
I am on the Wirral as well, and have a Vietnam era PBR (River Patrol Boat).It's an old cabin cruiser that I have modified to make into a mean looking PBR. It's 4' long and I took it for it's maiden trip last monday at Hoylake pool.All's well with it except the wash from the boat, ended up with some water in the boat and blew one of the speed contollers. It's twin screwed and goes very well.Got new speed controller today from Steve Webbs shop., so planning to give it another trip out this sunday, weather dependant.Will be there 11 to 11.30 am if you fancy coming down.It's based on the 30' boat the Americans used. There were several types of various shapes and sizes.
Cheers
Dunc
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red181

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Re: PCF (Patrol Craft Fast) Vietnam Swift boat build
« Reply #68 on: April 08, 2015, 04:01:05 pm »

hi dunc
I was there sat :}
im working sunday so cant play out and due to "other projects" I doubt I will be ready by this weekend  sure we will catch up soon. paul
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red181

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Re: PCF (Patrol Craft Fast) Vietnam Swift boat build
« Reply #69 on: April 09, 2015, 12:19:02 am »

started making the rudder tubes. Managed to do it so the rudder shaft sits in a rubber "o" ring, hopefully these will not leak, I'm not doing this job again!
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Perkasaman2

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Re: PCF (Patrol Craft Fast) Vietnam Swift boat build
« Reply #70 on: April 09, 2015, 12:18:23 pm »

A good video, the first of two in the series.


https://www.youtube.com/watch?v=_ZKuELYP2yQ
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red181

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Re: PCF (Patrol Craft Fast) Vietnam Swift boat build
« Reply #71 on: April 09, 2015, 06:01:25 pm »

really good, not seen that before, I have read all the Brown navy stuff, looking for pictures, video footage etc. 
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Duncan PBR

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Re: PCF (Patrol Craft Fast) Vietnam Swift boat build
« Reply #72 on: April 12, 2015, 08:01:02 am »

Hi Paul,
Ta for reply, hope to catch up with you soon.I'll ask my wife down soon to do a video of my boat and put on forum.
Your boat is really taking shape now, a good build blog.
Cheers Dunc
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red181

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Re: PCF (Patrol Craft Fast) Vietnam Swift boat build
« Reply #73 on: April 16, 2015, 10:22:56 am »

jig and wedges are ready!

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red181

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Re: PCF (Patrol Craft Fast) Vietnam Swift boat build
« Reply #74 on: May 03, 2015, 08:26:40 am »

it was back in the water yesterday, good news the rudders are dry, no leaks, but now the water pickups are leaking! >:-o and I still have that stuttering from motors, a signal issue or something going on.

Also, the rear engine covers are leaking, so its back to the bench and strip it all down, again <:(

I used the same receiver and in turn each esc in another boat, no problems at all, so changed out all the wiring for the second time. The rx is mounted nice and high, so its not a 2.4 and water issue. Water pickups refitted, and for now the hatch covers are just taped over, I will have to rethink how these are fitted to make them water tight. When running, the boats makes quite a bow wave so water is hitting the decks.

On full throttle I am getting torque roll, so will have to change to counter rotating props. It runs well so I suppose I could go slower! {-)

All ready for another test, and its pouring down
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