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  #61  
Old 07-05-2014, 10:36 AM
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SamSam SamSam is offline
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Originally Posted by schultzfactor View Post
SamSam: I was actually thinking of 2X40hp?
I'm thinking you are going to have issues of displacement, which means the size of the hulls weren't designed to float as much weight as you've already added with wood, fiberglass, etc., much less any big motors.

You should put it in the water right now, before you add any more weight, and see how it floats.

Here's a chart that rwatson made on motor weights in kilos.



So, put it in the water and have two guys stand on the back transoms to simulate two 40 hp outboards, while you stand where the center counsel is going to be. Plus put two full gas tanks aboard, two batteries, an anchor and equivalent weights for the center counsel and all supplies like a cooler of food, drinks, ice, fish gear, etc. Lay a few pieces of plywood on where the decks will be. If you plan to take any passengers, add some seating weight and have those passengers get on now. The two guys on the transom don't count as passengers, as they are 'outboard motors' for the moment. It would be best to rig a couple lines to the bows so the 'outboard' guys can lean way back over the water and heavily jump up and down on the transoms, better simulating real outboards.

As long as it's glassed and the wood is sealed, clean fresh water won't hurt anything, it will dry off. But it will give you a pretty good idea of how it floats and how much weight you can add, if any, and where you can add it.
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  #62  
Old 07-05-2014, 07:06 PM
Mr Efficiency Mr Efficiency is offline
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Yeah I'm not a Hundy on that yet. I have a bracket for it but thought of modelling two tubular Ali brackets? I need to see what the tipping point is first to see firstly how much weight I can throw on the back and then how far back I can put it. Any thoughts?
No brackets ! Those skinny hulls will not tolerate that kind of set-up. But as Sam sam says, you need to see whether you can accomodate even transom-hung engines weights. But you would be wise to forget extending the mounting point further aft, some perfectly good power cats turn into dogs that way.
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  #63  
Old 07-05-2014, 11:55 PM
schultzfactor schultzfactor is offline
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Great thanks. It's in my plan to put it in the water pretty soon. The hulls are actually quite a bit wider than the original ones, but it is something I am worried about. I suppose that is the risk she I just whacked her together. At the top of the tunnel they are 500mm wide and at the bottom they are 220mm wide. I'll make a drawing of the hull profile from the bottom and upload it. At the midship the hulls are nearly 500mm wide at the keel.
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  #64  
Old 07-06-2014, 12:02 AM
Mr Efficiency Mr Efficiency is offline
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Sounds extremely slender. The ability to bear weight aft will be very limited.
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  #65  
Old 07-06-2014, 01:40 AM
schultzfactor schultzfactor is offline
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Might be, if I have to change the stern so be it. I have been thinking based on previous comments to create more rocker aft. I'll see how it floats and go from there.
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  #66  
Old 07-06-2014, 05:31 PM
schultzfactor schultzfactor is offline
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the stern

here are some pictures with dimensions. thoughts are appreciated thanks. I have a few alternatives if this is really not going to work.

1. Rebuild the stern and pontoons aft.
pos: improve hydrodynamics and displacement?
neg: none really.

2. add foam sponsons inside each pontoon and fibreglass onto the strucure.
pos:easy retro fit.
neg; i know you're going to say unknown hydrodynamics and perhaps a bit ripshy, but then this whole thing is an unknown adventure.

3. cut out a wedge as drawn.
pos: easier than rebuild.
neg: perhaps still not enough displacement.
Attached Thumbnails
GOP Home Build-transom-pics.jpg  GOP Home Build-stern-wedge-removal.jpg  GOP Home Build-sponsons.jpg  

GOP Home Build-038.jpg  
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  #67  
Old 07-06-2014, 05:49 PM
schultzfactor schultzfactor is offline
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hull turned upside down

might give a clearer understanding of the hull shape.
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GOP Home Build-hull-inverted.jpg  
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  #68  
Old 07-06-2014, 06:14 PM
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you might want to install a motor well in the bridge between the hulls, forward of the transom, so the motors weight is forward of the stern and not hung on aft of transom.
fuel and batteries could be placed even further forward for balance. Maybe under a seat.
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  #69  
Old 07-06-2014, 06:23 PM
schultzfactor schultzfactor is offline
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Yep that could work well. Ameracat do almost like a tri hull pod for a single outboard pod. I could easily do something similar that would add to the displacement significantly.
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  #70  
Old 07-06-2014, 06:44 PM
schultzfactor schultzfactor is offline
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centre pod

Like thismaybe. Ignore the hydrofoils they are just for fun.
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GOP Home Build-centre-pod.jpg  GOP Home Build-centre-pod-2.jpg  
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  #71  
Old 07-06-2014, 07:23 PM
schultzfactor schultzfactor is offline
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Ameracat hull

Here is the Ameracat one with a central pod?
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GOP Home Build-image.jpg  
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  #72  
Old 07-06-2014, 08:57 PM
Mr Efficiency Mr Efficiency is offline
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What is the length of it ?
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  #73  
Old 07-06-2014, 09:12 PM
schultzfactor schultzfactor is offline
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the centre hull, not sure. I would think itmight be as long as 2m?
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  #74  
Old 07-06-2014, 09:14 PM
schultzfactor schultzfactor is offline
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and it looks as if this hull goes from symmetric hulls fore to asymmetric aft?
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  #75  
Old 07-06-2014, 09:16 PM
Mr Efficiency Mr Efficiency is offline
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No, the length of your boat ?
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