28 BERTRAM EXPRESS CONVERSION

Questions about boat repairs with our resins and fiberglass: hull patches, transoms and stringers, foam, rot etc.
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Mbiggerstaff
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28 BERTRAM EXPRESS CONVERSION

Post by Mbiggerstaff » Mon Nov 24, 2014 1:22 pm

I have had this old 28 Bertram sitting around for 6 years. I started researching conversion and ended up on this site due to Daytrip's topic. I am planning a conversion to an express design with a hard top without a tower. My original intent was to convert to outboards but I am having second thoughts. My current boat is a True World Marine 28. It has a center mounted Yanmar 315 hp jackshaft to an outdrive. The boat previous to the TWM was the same setup. This is a great way to rig a boat. The economy is incredible at only 9 gph at 25 kts. I have not been able to find any post of a Bertram conversion to a single screw. Any help/suggestions would be appreciated. The decision time will not be for a couple of months as the demolition will take place in the evenings and weekends. I will try to keep a photo library as we go along.



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Re: 28 BERTRAM EXPRESS CONVERSION

Post by jacquesmm » Mon Nov 24, 2014 1:44 pm

Joel is out of town and I will start the reply

From a design point of view, the weight distribution should be fine with a jackshaft engine assuming this will be an I/O.
There should be no problem to run the boat as a single screw.
I prefer twins because the props are protected.
I can give specs for the engine girders. We can also spec the fiberglass work on the transom. To take the thrust of the outdrive, we'll need to reinforce that transom. How about starting with some pictures once the demolition is done? That way we'll see exactly what you have.
Jacques Mertens - Designer
http://bateau.com

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Re: 28 BERTRAM EXPRESS CONVERSION

Post by DAYTRIP » Mon Nov 24, 2014 4:36 pm

Hey Mbiggerstaff, I am doing mine as an express as well. I will post a cadd drawing of the concept elevation. Take a look at the post of the 258 mako project that I was doing.I thought of doing something like you are talking about with my old 28. I was looking at the 450 cummins in an inboard config. It was more cash then I was willing to put into it jack shafts are cool.

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Re: 28 BERTRAM EXPRESS CONVERSION

Post by Mbiggerstaff » Mon Nov 24, 2014 7:37 pm

I have a Yanmar 6lp 370 hp that I can get at a reasonable price. My TWM has a 315 hp 6lp. I cruse at 25 knots and max out at 30. I know the Bert will be heaver and have more surface area in the water. Not sure 370 hp would be enough. Look forward to the cadds. Have added pix to album in gallery on this site, still trying to get them into this post. Working on Mac so instructions in read this first don't fit.

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Re: 28 BERTRAM EXPRESS CONVERSION

Post by DAYTRIP » Tue Nov 25, 2014 8:01 am

Couple thoughts. Let me know what you think

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Re: 28 BERTRAM EXPRESS CONVERSION

Post by DAYTRIP » Tue Nov 25, 2014 8:03 am

Image

Image

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Re: 28 BERTRAM EXPRESS CONVERSION

Post by Mbiggerstaff » Tue Nov 25, 2014 9:40 am

Got the pix thing figured out. Daytrip, thanks for the drawings. That is what I had in mind. Will get the top off and then decide on windows. Was hoping to keep front glass in some fashion to keep boat character and have side glass cut to express style. I have read that the split glass windshield leaked a LOT. Never had mine in the water so don't know. Got the boat safely to greenville , nc and got it cleaned up. Looks like a new boat.
Last edited by Mbiggerstaff on Tue Nov 25, 2014 9:49 am, edited 1 time in total.

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Re: 28 BERTRAM EXPRESS CONVERSION

Post by Mbiggerstaff » Tue Nov 25, 2014 9:42 am

Image

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Re: 28 BERTRAM EXPRESS CONVERSION

Post by DAYTRIP » Tue Nov 25, 2014 10:50 am

Cool! I had a 28 before this one and no issues with window leaks. That one was a 73 so not sure I would let that woorry me. I am leveling the floor to one level on mine and based on that the floor hieght at the v-berth is level with the v berth seating/couch. with that in mind the windshield is below your eye level. i still like that idea as well but my family thinks it looks to old which means classic in my mind! If you have any adjustments or thoughts let me know. I can get them incorporated for looks. Drawings should be "scaled" or close anyways.

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Re: 28 BERTRAM EXPRESS CONVERSION

Post by Mbiggerstaff » Sun Nov 30, 2014 5:44 am

Got the cabin torn out and a trailer loaded for a trip to the dump later in the week. There sure was a lot of heavy plywood used back in the 70's.

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