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Author Topic: Miami 55 help required  (Read 2380 times)

fasttrack

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Miami 55 help required
« on: November 05, 2009, 03:54:16 PM »

Can anybody out there send me some photos of the engine bay and rudder assembly on the Prestwich Miami 55 kit .My wife bought the kit from Prestwich models and it comes with the Zen 7 engine with all the required mounts etc.The problem is that the last model i built was 20 years ago and it was a timber construction off shore racer.Things have moved on since then and to be frank i am lost as to where to start with this bag of bolts and plates that came with the kit with very sketchy assembly instructions,i can only pressume that the kit is designed for someone with background knowledge of this type of build which i dont have but i would like to try.On calling Prestwich they said to try the instructions that are posted with the Sigma 51 technical section,on looking at that i could see some similarities but it was not the same as the kit the comes with the Miami 55.
Any advice or pictures that will help me assemble this boat would be gratefully appriciated as pictures would bring clarity to the sketchy plans that are availiable.
Thanks
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Bill D203

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Re: Miami 55 help required
« Reply #1 on: November 05, 2009, 06:04:21 PM »


Welcome!!
I don't know if these are of any help?? The Blue boat is the tail end of a Makara owned by Simon and the tail end of my new stelth boat.
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w3bby

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Re: Miami 55 help required
« Reply #2 on: November 05, 2009, 06:27:02 PM »

You've checked the Miami instructions as well http://www.prestwich.ndirect.co.uk/miamidrawing.htm Those coupled with the pics from the Sigma build should help you along without too much trouble.

What is your major problem at the moment? Generally how to fix the mounts to the engine, mount the engine in the boat or specifics such as measurements?

Does this link help you any http://www.xtremercboats.com/phpBB/viewtopic.php?f=2&t=13167 sorry it's a Sigma again....

fasttrack

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Re: Miami 55 help required
« Reply #3 on: November 06, 2009, 01:58:19 PM »

Thanks for the pictures,this does help, and the main issues are as follows: How do you fix the aluminium quite engine mounts supplied in the kit to the hull,Ive been told to use Isopon P38 is this correct ?,if so how do you go about obtaining the the correct height and angle for cutting them,definitely don't want to get this bit wrong.
The Miami 55 has an offset on the prop shaft of 3mm from centre of transom so does this mean you offset the engine by the same to keep the shaft straight or do you put a bend in the shaft to compensate for this so the engine remains central in the hull ?
.Do you have to fuel proof the interior of the hull before you even start any fitting out or is this not required in a hull of this type ?.
Does the pitch of the engine get dictated by the angle of entry to the hull governed by the prop shaft support or again do you bend the flexi shaft to suit a given angle.
Does the prop shaft require any further support from the transom to the engine if so how is this achieved and at what location.
Rather than bombard you with any more questions, if these could be answered first so you don't get bored pointing out the bluntly obvious i would appreciate it,sorry if the questions seem dumb to ask but like i said i haven't built anything like this before so i need all the help and advice i can get and as i live in Essex i think i might just pop up to the Stevenage club one Sunday to have a look around or do they shut down in the winter months?
Thanks again
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Bill D203

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Re: Miami 55 help required
« Reply #4 on: November 06, 2009, 03:50:43 PM »

Ok lets try !
At the moment the lake is closed due to alga probs. We are all hopfull it will be open very soon. We are normally there from 9 /12 Sunday mornings.
Engine Mounts. I don't use them. I use a stringer frame set up which is fiberglassed into the hull. I have seen to many engine mounts break out.
Engine Angle. I an ideal world it should be straight in line with the prop however the prop tube will need a bend in it . I find if you get the engine as low as you can in the boat it will ride allot better.
Prop offset.  Some will argue about this. I have mine in the middle and it works just fine . Others set theres up with an off set.  which ever way the engine most set in the middle of the boat  with no offset.
Here is some pics of my Makara set up and my new boat stringer frame before i fitted it in the boat.
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Bill D203

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Re: Miami 55 help required
« Reply #5 on: November 06, 2009, 03:52:40 PM »

Sorry Should have posted this pic
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w3bby

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Re: Miami 55 help required
« Reply #6 on: November 06, 2009, 05:59:53 PM »

Thanks for the pictures,this does help, and the main issues are as follows: How do you fix the aluminium quite engine mounts supplied in the kit to the hull,Ive been told to use Isopon P38 is this correct ?,if so how do you go about obtaining the the correct height and angle for cutting them,definitely don't want to get this bit wrong.
I used epoxy, chopped fibres and thickener see pic. As your hull is polyester I guess Isopon would work or do a mix of polyester, chopped fibres and a thickener.


Quote
The Miami 55 has an offset on the prop shaft of 3mm from centre of transom so does this mean you offset the engine by the same to keep the shaft straight or do you put a bend in the shaft to compensate for this so the engine remains central in the hull ?
Motor in middle and bend the shaft. The L ynx in the pics here is offset, the Sigma is not and requires a touch of left rudder to keep her straight.
Quote
Do you have to fuel proof the interior of the hull before you even start any fitting out or is this not required in a hull of this type ?
Not really but a painted interior is easier to clean. I have used both epoxy paint and smooth Hammerite.
Quote
Does the pitch of the engine get dictated by the angle of entry to the hull governed by the prop shaft support or again do you bend the flexi shaft to suit a given angle.
Bend the flex shaft to suit
Quote
Does the prop shaft require any further support from the transom to the engine if so how is this achieved and at what location.
Yes. about 4-5cm from the collet is OK. Build a bracket from plywood and glue it into the hull. You can see mine here.

Bombard away, better to ask too many questions than not enough :-))

fasttrack

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Re: Miami 55 help required
« Reply #7 on: November 06, 2009, 10:53:08 PM »

Thanks Guys,
I now have something to work with,this weekend the build will start.
Fasttrack.
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