new boat, sharkcat sportsman. getting bigger tanks, help on how to do new floor.

[lembo]

Hi guys
Just put some money down on my new boat!!! woo hoo. waved goodbye to the 5.2 kevlacat, and soon il have a flash re furbished sharkcat sportsman in the driveway. its one of the nicest ive ever seen. bigger beds and deck area then the kc, and I recon it will ride a little better too. and best bit its a factory podded one, which is rare as hens teeth. a few members on here know the boat very well.
now back to my question, the floor is in pretty good nic but its the original floor. I think the tanks are 120l a side but a very strong fuel smell has come out of one of the hatches (possible cracked tank) ?, so im thinking of pulling up the floor and getting new larger tanks put in, I believe there stainless tanks glassed in.
now anyone done this process in a sharkie ? any help would be appreciated.
im thinking of cutting floor out bout 100mm from the sides and doing all the tank stuff then putting new laminated ply down then glassing over floor and overlapping onto the 100mm bit around the edge ?
anyway that's my plan. any comments would be appreciated.
thanks.

[captain rednut]

Hi I have just finished my second Cat fuel tank replacement this year so attached are the pictures of before and after, this one in the pictures is a Bruce Harris 18ft shark cat and the other one we done is the same make but a 28FT version, WE also packed the measured amount of buoyancy foam in both boats to give Positive flotation.
Regards JIM

[Rip it up]

Is that a nasty brown liquid I see in the first picture red nut? Awesome.

My only experience with cats are the newer powercat marine versions with the moulded floors. One piece items from gunnel to gunnel.

The photos red it have some the timber supports spanning the decks. The join to the tunnel would be my concern. Cats are notorious for flexing around the tunnel to floor join. And taller supports across the tunnel might help stiffen or weaken depending how far you go with them. If you could replace the originals with a taller section and cove and glass the new ones to the tunnel effectively you could create an I beam structure over the tunnel. Make the new supports wider too should help with the floor sheets adhesion value. 2" wide verse 3" wide supports would be an extra 50% glue.

The 100mm step on the outside of the hull wouldn't hurt either. But I would attempt to cove and glass the underside of it to the hull before you lose access with the tank install.

New aluminium tanks could be installed with the tank supported up off the hull using soft foam offcuts. Then a rig made to stop the tank pushing upward whilst the pour in 2 part expanding foam is punched around all the surfaces. Let it extend up above the intended floor height and trim it back to the correct height with a handsaw.

Remove your hold down rig on the tank and install the floor.

Well that's my input anyway.




Damo's dodgy boat building repair shop.

[The Mad Cat]

This how not to do it.
I was talking to a fiberglasser the other about shark cats and he told me about a boat he had to repair, the owner decided he needed new tanks so removed the old tanks from the outside of the hulls "yes he cut the side out of both hulls". then had to get someone who knew what the were doing to repair his mess. I still laugh about this when I think of it.


TMC

[lembo]

wow he cut the hull on the outside ,what a complete idiot.
as the boat has side pockets which are maybe 70mm off the floor, it will make it ectremenly hard to but all the way to the side if the boat. so the plan was cut about 100mm from the edge ( where floor meets boat side) along the front and at the transom and on the sides just as close to the side pockets as possible, then do all the work I need to do with tanks underfloor and then when putting floor down use the same thickness ply as original, laminate it then use stainless screws in a resin filled hole to attatch it to the top of the bulkheads/crossbeams also use some adhesive. then run a couple layers of glass over whole floor and overlap glass onto my edges that I left. hopefully floor will blend in to the same height and be strong. I should be able to glass easily under side pockets, just to small to get saw under.
and hopefully I can get tanks out with that lip around the edge.
well that's my plan???? sound ok???? ive never done this but will attempt it.

[captain rednut]

Hi Lembo
Did you find any tips out of the photos??? or is it totally different to yours??

[Rip it up]

Lenco the problem with doing a butt join on the floor timber is you get thin layer of glass which has a void (or at maximum a Non structural filler underneath it. ) so it won't get a full I beam style construction. It will nearly always hairline crack along the join from flex.

You could make a 3" wide solid glass panel to epoxy glue under each existing lip. From bulkhead to bulkhead. This at least give it a chance. Epoxy glue to attach it. And then glass over the join.


Damo's dodgy boat building repair centre.

[Noelm]

I have a few photos of when I did mine, PM your email and I will try to dig them up, the tanks will be about 75mm below the floor, the actual floor is quite thin, and has those cross over beams from side to side, you will probably have to cut one to get the tanks out. I "thought" the podded cats had 200 liter tanks??, but I could be wrong, if I did mine again, I think I would cut nice neat holes above the tanks, and fit removable floor sections rather that glass them back over, the removable sections could be sealed and even though difficult to remove, at least it would be possible. The tanks will run from the filler towards the rear, pretty simple floor really, because unlike a mono hull, the floor does not provide hull rigidity, it is simply to stand on (if you get what I mean)

[lembo]

yeah I suppose I could epoxy a part underneath the edge I leave, I wouldn't mind cutting out all the way to the edge and running glass up the side a little bit as it would make it much stronger but man cutting all the way to the edge, especially under the side pockets would be crap. I don't think there 200l tanks noelm. current owner says 120l a side. I don't have possession of the boat yet, but yeah the floor is surprisingly thin. seems thinner then what my kevlacat was, but at least the current floor is laminated on the underside as my kevlacat was bare plywood. I will PM you my email, any pic is a good pic.
Captain Rednut thanks for the pics, I don't really know if this is the same as mine as I don't have the floor up yet, but from what I can see through the inspecton ports it looks the same. but the tanks I saw throught the port was fibreglass. but the owner told me it was stainless tank glassed in ??

[Noelm]

If your boat has a series of inspection ports in the floor on each side, then the boat was built to survey (well at least partially) and the tanks will be metal (stainless) encased in glass, lots were like that, the floor will probably be Masonite, and nailed with galvanized flat head nails to the cross over beams. When I did mine, I left about 50mm or so all the way around the sides, and cleaned the old glass off and then went over it with the new floor, grassing right up to the bottom of the side pockets. I also just made up some bog and troweled it on the cross over beams before screwing the ply down, you will have big trouble fitting the sheets in, because the side pockets stop you laying them down, I did mine with a join down the centre, made it so much easier and neater.

[captain rednut]

What happened Lembo are you still with us????

[lembo]

still with you, under your floor looks the same as mine,i haven't pulled my floor up yet but from what I can see it looks the same. but my tanks are glassed in. gee I hope there 200litre noelm.it does have a inspection port for each underfloor section so I assume it was surevey built, no foam tho. it will be a little while until I do this job, im just trying to plan it.

[The Woo]

I'll be surprised if they're glassed in. They did often cover them in flow coat, but I've not seen one with the tanks glassed in.

[kaypee]

There may be some info on the threads on here when your new boat was refurbed Lembo???

[Dean1]

Congrats on the purchase Lembo. I was meant to go on the trial run with you & Faron that morning but was nursing a hangover instead. Youv got yourself a tidy tub there. The tanks are 110ish ltr im pretty sure about that. With big tanks and bigger donks this boat would be the bomb. F 100 Yammys I say. The 560 Sharky we just sold had 180 ltr tanks and they were great with 2 strokes let alone 4s. Happy days