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Transom/rear deck modifications
Dear All
fixing up ski boat 22', have changed transom setup from outboard to Arneson surface drive Need to modify back of boat as presently wash is likely to come over transom as originally boat was setup for outboard So was thinking as engine sits forward of the transom as have gearbox and dropbox mounted between engine and transom, then need to cover in the rear was thinking of using current deck lines, and then would construct engine hatch to cover engine If this was closed in then would help to protect the trim tabs pumps, Arneson trim pump and bunch of other stuff from water in back of boat What material would one use to close of the back deck of the boat, was thinking along the lines of using the Coosa 1/2" board (or marine ply) reinforced, with ribbing/structure to support, as may want to walk across the back of the board and need plenty of strength assuming would just fabricate the structure, as opposed to making mould to build a outer skin/gelcoat etc Then laying the usual 2* layers 2 oz CSM, 17 oz Multi axial fabric, then would need to gelcoat If https://cimg2.ibsrv.net/gimg/www.off...999c4ad0af.jpg looking from back of transom forward https://cimg8.ibsrv.net/gimg/www.off...1d742b0182.jpg As boat is now open at back https://cimg9.ibsrv.net/gimg/www.off...b9421c3cf4.jpg idea to fill in back by falling current deck lines anyone can throw us some pointers would be good??? here are some pictures of what I was thinking current and filled idea let us know what you think? Brett |
like to see more pics of your project.
the idea that you drew in is a good one, making look stock like it was a factory option. but add to it about 3-4 inches hanging out over the transom, to help stop reverse prop wash from doing what your trying to avoid. look up member glass dave for materials and techniques. skip ahead to 1:56 (good video, of another members arneson conversion, it was a good thread as well) |
outonsafari
Thanks for the video clip, always liked Donzi don't see to many of them down under the angle of transom if I can recall is close to 20 degrees except for the lower transom where arneson bolts up, where I encapsulated a wedge to get the angle needed Outside of Transom at this stage has not been cleaned up, as inside boat at present only decent picture of boat is prior to ripping the stringers and transom out, however apart from lower transom angle change rest of transom is same angle. Donzi seems to be not raked as my 20 degrees transom, not sure how this would play out? I've never measured the dead rise https://cimg1.ibsrv.net/gimg/www.off...251ebfd9d1.jpg https://cimg0.ibsrv.net/gimg/www.off...a2d124b520.jpg prior to transom modification still 20 degrees above arneson mounting https://cimg4.ibsrv.net/gimg/www.off...d9848a81b8.jpg arneson mounted after transom mods https://cimg5.ibsrv.net/gimg/www.off...6666b630db.jpg |
started playing in weekend with rear deck
built some bracing for 40x20mm hardwood, bolted (5/16" SS) and glued, then rebated the 2 main battens for the 3 cross braces decided to use West epoxy 105/206/413 filler as had it here Then started laminating 6mm Gurit board for rear deck 43x24" with Vinyl Easterhttps://cimg8.ibsrv.net/gimg/www.off...a1d776dd76.jpg https://cimg9.ibsrv.net/gimg/www.off...1eb99a81a9.jpg https://cimg0.ibsrv.net/gimg/www.off...ad46e6265a.jpg Used 1*2oz CSM, 1* 25oz biaxial on one side sandwished 2oz CSM in between another 6mm board will lay 2* layers of 2oz CSM and 25oz Biaxial which should bring the new deck +1mm lower than original rear deck Need to finish fabricating lip on the new rear deck |
spent weekend finishing laminating the insert
sealed the timber with VE used 20* 3/8" dia x 2.5" long stainless tapered head bolts and nylock nuts made up glue with VE and west #403, #413 high strength filler recessed head bolts and PB over head already for the 2oz CSM, 27 Oz biaxial coming together it will be big improvement over the original open hull https://cimg1.ibsrv.net/gimg/www.off...cc3d50418e.jpg laminating the front fascia for new rear deck insert https://cimg0.ibsrv.net/gimg/www.off...5507c55d83.jpg gluing fascia on to battens https://cimg3.ibsrv.net/gimg/www.off...efe8692d9d.jpg rear view https://cimg8.ibsrv.net/gimg/www.off...d17b7399d2.jpg glued and bolted new rear deck insert https://cimg9.ibsrv.net/gimg/www.off...fb1d49454a.jpg side view |
https://cimg5.ibsrv.net/gimg/www.off...4e21e62ce2.jpg
filled rear deck https://cimg0.ibsrv.net/gimg/www.off...4db53282c9.jpg filled rear deck https://cimg4.ibsrv.net/gimg/www.off...7cc5cc55c4.jpg bolster seats which may use https://cimg2.ibsrv.net/gimg/www.off...346d3f5709.jpg 1. Here is the update with rear deck insert: placed a skim coat of PB on rear deck to fill the coarse surface finish from the 27oz biaxial cloth Jumped up and down on the deck a few times, so seemed to pass the 100kg Oze test. Needs to be filled and painted, however will get to this latter 2. finished fabricating aluminium stringer support plates and engine mounts from 10mm (3/8" angle and plate managed to get a a local welder who used a mig to weld up my handy work all came out fairly good, the starboard side had slight misalignment with stringer plate but managed to drill out 3 of the 1/2" bolt holes to 5/8" and all was good, when finished there will be large stainless steel washers and S/S flanged nylock nuts used all 316 S/S threaded rod epoxied into stringers and under floor On the vertical connected S/S bolts, drilled out holes into stringer then epoxied in 10mm x 40mm long S/S coupler nuts so they aren't going anywhere made up mid-plate between engine and crash gearbox from 6mm aluminium plate, which bolt down in similar way through top of stringers 3. fitting Char Lynn Helm 201-1007-003 (211-1007-003 new number) pump into dash, have a 3" column but dash is very thick and need a 6" column, have ordered waiting 4. Measure up the seats and location, could have room for 3 seats as i have 1930mm (76") across inside of boat and seat are 500mm wide wont have room for rear seat, wanted to run some offshore Donzi/scarab seats, however know where to be seen down under seats need to be mounted to floor so perhaps maximum 4-5" height to pack seat. I was asking in another post about suspension under seats However most probably uncommon for ski boat (fun) as most of time thgese are on lake or river, however I'll be running in bay in harbour so will be taking a few waives thought I might as well looks at this while setting up steering 5. pulled out the closed water system which managed to get 2* complete mercruiser 7.4 litre system from a guy which was repowering his 38ft boat with new 383 chev which came with there own closed cooling system, so picked these up at good price, 6. Purchased 1.25" water pickup, ball valve, and have Gil strainer that needs to be placed somewhere 7. started cutting some holes in dash for the Gaffrig Gauges 8. This is the problem when your starting with just the hull and its not a factory build, everything takes time to fit when youre doing it yourself so many things to think about present, but its good to start the engineering side, as stuff at present going back into boat to set up I'll post some pictures shortly |
attached the pictures as were on my work PC
Need to position closed water system in front of engine, was trying it out at rear to see how hoses would work out https://cimg7.ibsrv.net/gimg/www.off...4067eac15b.jpg Fabrication using 10mm angle/plate along stringers and mounts to pick up the mercruiser saddle mount https://cimg9.ibsrv.net/gimg/www.off...b9f3da2a0e.jpg https://cimg0.ibsrv.net/gimg/www.off...c8da4e61dc.jpg https://cimg1.ibsrv.net/gimg/www.off...acdd003762.jpg https://cimg1.ibsrv.net/gimg/www.off...3d45f7ca7d.jpg checking the centre of motor with laser pointed mounted in cam bearing location on engine if you look you can see red dot in centre up front |
playing around with closed water systemhttps://cimg9.ibsrv.net/gimg/www.off...0ca7dfa9e4.jpg
https://cimg8.ibsrv.net/gimg/www.off...f3cd16c329.jpg https://cimg0.ibsrv.net/gimg/www.off...8e44bdd596.jpg https://cimg1.ibsrv.net/gimg/www.off...67217f7d9e.jpg https://cimg4.ibsrv.net/gimg/www.off...352a686435.jpg this is better picture showing crash gear box and drop box before going out transom to arneson drive |
this is awesome, that boat will be a ton of fun when it's completed.
keep the thread updated, thought you gave up on it. |
not given up, just need to work as well
I'm starting with just the hull, and need to add in the stuff as we go, however this is first boat project need to think ahead so don't stuff things up and have to redo the work on the subject of closed water cooling was going to use conventional 7.4 litre mercury heat exchanger as shown in picture. If using HX to cool half system, how much additional water would one need to allow in puke tank/radiator over flow/ expansion tank to cool twin turbo 502ci or 560ci BBC Do you think additional gallon tank would be sufficient Why use half cooling system? as I have the twin mercury HX here and would like to utilise them, and am mindful of the additional heat that would be transferred into HX in i went full cooling system and routed the closed cooling system through aluminium exhaust So starting off conservatively |
Gil sea strainer installed above water level
Have purchased some chemical called CFS CFS Clean Flush Soak - Descale Lime, Rust, Calcium and Marine Growth to clean out the gunk in Heat exchangers, will have this done over weekend water pickup installed 16" from rear transom and 10" from centre line of hull Had to allow for the centre bunk of trailer https://cimg8.ibsrv.net/gimg/www.off...26e7b2af46.jpg Gil sea strainer installed https://cimg9.ibsrv.net/gimg/www.off...5938ead47b.jpg https://cimg8.ibsrv.net/gimg/www.off...cae48b91d1.jpg pickup 1.5" located 10" from centre of hull, 16" from back of transom https://cimg5.ibsrv.net/gimg/www.off...1b936ed4b5.jpg HX needs clean out |
Soak HX over night for 12 hours
no gunge now clean as a whistle good stuffhttps://cimg3.ibsrv.net/gimg/www.off...5ca91b345c.jpg HX cleaned day https://cimg4.ibsrv.net/gimg/www.off...472ac58859.jpg HX cleaned night |
Looking for some suggestions of whether to install one piece of two piece engine hatch
This boat is 22ft engine bay is 43" (3.64') long from rear of transom x 74" (6.16') wide from front of engine block to height of gunwale is 12" so looks like carb engine would fit under without any issues whats the best materials to make the hatch out of plywood 1/2", and fibreglass? Not to sure what the weight of hatch would be, assuming would need a electric lifting ram, unless manual ram would work? any suggestions of brand or type of ram and hinges as not familiar with these setups? any suggestions would be helpful as you have guessed in looking at pictures there will no back seats in boat cheershttps://cimg7.ibsrv.net/gimg/www.off...6ece51eb17.jpg https://cimg8.ibsrv.net/gimg/www.off...4b14acf4f6.jpg https://cimg9.ibsrv.net/gimg/www.off...6bb8c8965d.jpg https://cimg0.ibsrv.net/gimg/www.off...1170f203da.jpg https://cimg1.ibsrv.net/gimg/www.off...a7ae8233c2.jpg was thinking to have a pillow top, and may run a scoop |
Glassdave
Im assuming one would use plywood as it has a ,little more tensile strength than the Gurit board that I used on rear of deck? cheers Brett |
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