Stringer repair

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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So your the one guy that bought the clear valve covers.....LOL

look like old Hardin marine log manifolds minus the snails for a jet boat feeding the turbos

did you machine the timing covers for the Gen 6's or are you still using a single roller timing chain?

is the draw thru turbo responsive enough to putt around a bay?
 

proshadetree

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Jul 19, 2008
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Poly is cheaper, from what I would do to that boat 5 gallon is a good start. But I would find out if the modifications that are already done to the hull are poly or epoxy. Poly will not stick to epoxy. Vinyl ester sticks better but epoxy sticks to everything. Down side you cant gel over epoxy. My opinion on that center stringer was more for an outboard. Most IO boats don't have them. If you stick that twin turbo monster in there make sure you mount that transmission extremely well. Nice eye candy by the way.
 

bjf66

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Scott
Did I buy the rocker covers from you, nice
I managed to find some others at a swap meet and cleaned them up after redoing the perspex, now shown on the 509 Gen VI finished (see attached)
Actually I used the carb on the draw through setup to run the engine on floor for 20min
I have throttle body, which could be turned into blow thru if needed, or keep with draw thru setup with efi

Have similar twin turbo setup for the 509 ci engine

Proshadetree
Yes I think with epoxy its going to work out a little pricey
Had a chat with resin supply today and they suggested Vinyl eater around US$150/5 Gal..seems much better deal than US$400 +/5 Gal, although they indicated working time would be less than the west 105/206 slow hardner as over christmas period starting to warm up down under

Think I'll be cutting in front of bulkhead in weekend to check the ballast tank, as dont really need this, then will check the main stringers to ensure they are okay

The boat Ive been told the boat was 26ft and cut down to 21 ft, however have been unable to track down builder, I would imagine that originally the manufacture used poly
The glass is thick
I was thinking of making a box frame and dropping motor and daytona gearbox onto stringers with some cross bracing,in aluminium and tied to the engine plates
Need to get the transom sorted and arneson surface drive to then work out where the parallel drop box will go
 

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proshadetree

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I will agree that the original boat is polly most are. My concern is the modifications done. What were they done in? If not taken back to known poly kind of iffy. Cant wait to see more pics of this ride. Looks like it is going to be a blast
 

bjf66

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Is there anyway of testing the glass some how to see whether epoxy, ploy, or vinyl ester?
sorry Im new to this fibreglass stuff
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Scott
Did I buy the rocker covers from you, nice

I dont make them , Just know about them. talked to the guy making see-thru valve covers at clear vue concepts on the Hot Rod Power Tour once . he said he finally got NHRA approval so he his hoping to sell to race teams. I mentioned that they weigh about 10 times a 18 gauge milodon cover weighs or about 15 times what the carbon fiber ones weigh and the chances of selling a heavier part to a race team would be slim to none. he looked at me with his head cocked to the side.

Novel to watch the valve train for about 2 minutes. I myself am going wrinkle finish on the motor. doing my cast pan as wrinkle black this afternoon, the valve covers, intake, carb and timing cover will be wrinkle red. the pretty endurashine will be covered with a layer of wrinkle paint
 
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ondarvr

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Is there anyway of testing the glass some how to see whether epoxy, ploy, or vinyl ester?
sorry Im new to this fibreglass stuff


Not easily, but the chances of it being epoxy are slim to none, and it makes no difference whether it's VE or polyester.
 

gsxrdan

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Aug 28, 2016
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Thats a slick looking hull! Nice to have another aussie doing a boat build, good luck with it. I think i could provide a good home for 1 of those shiny new bbc's :very_drunk:
 

bjf66

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Haven't done much over christmas, other than getting VE resin, and cloth ready, managed to put down 200 litres of house roof paint, so another job out of the way
spent the other day grinding down to some good fibreglass on floor inside stringers, then turned my attention to stringers and gave them the hammer test
found some rot on right hand stringer (looking from back of transom, and kept going until I found solid wood, which was around 30" forward of transom, started to look at left hand stringer and found there was less rot, and started to dig this out.

the rest of the stringers left and right sounds solid with no visual laminations
so the question is now how do partially do a stringer rebuild?
1. I'm assuming that I clean up existing stringer
2. make a stepped joint between existing and new stringer
3. stinger will be 12x2" x30" long
4. Use peanut butter for glue joint between stringers, and floor, add weight to hold down
5. then lay cloth up, was going to use axial woven 17oz, and 35oz cloth (managed to pick this up reasonable cheap) to lay up


Questions:
- I'm not sure what timber was used in stringers, assuming I'm looking for something like hoop pine (Douglas Fir/Oregon), and not a heavier hardwood?
- does anyone see any issues with the stringer joint with overlap of 6", I'm assuming once all cloth is down its all one piece sealed in the heavy cloth and fibreglass
and of course some pictures
cheers
Brett
 

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JASinIL2006

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If I were doing it, I'd probably want a stronger joint. I'd probably sister a board alongside the joint, with at least 12" overlap past the joint. I'd also be sure to use mechanical fasteners, like thru-bolts, to lock the pieces together before glassing.

You can use plywood or engineered wood (exterior grade) if you want. Probably stronger than dimensional lumber.
 

bjf66

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Thanks for quick response, yes that sounds excellent way to go to increase overall contact area of the joint, I was looking to possible build aluminium box to support motor, gearbox and casale dropbox to add some strength, however have plenty of 34oz cloth if I'll get the strength that way
 

Woodonglass

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I'd recommend sistering your new stringer to the old like this...

SisteredJoint.jpg


Use thickened poly to glue and screw (deck screws) the 1/4-3/8" plywood to the sides of the butt joint. Make sure to predrill for the screws and coat the holes and the screws with the thickened resin.;)
 

bjf66

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Woodonglass
Thanks for your suggestion, so the but joint is okay or I should step the joint and then reinforce by biscuit/sistering the joint
also would the stringer be better with using 0.5" marine ply and building up by sandwhich ply, or just adding the 50mm timber for the stringer?
My only concern with joint is planning to put 600hp down on the stringers
cheers
Brett
 

bjf66

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managed to get one stringer cleaned up tonight, need to cut away floor to get access so i can lay up glass on outside of stringer
 

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Woodonglass

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laminated 1/2"plywood is much stronger than dimensional lumber. you can scarf or overlap the joint but the joint illustrated will be more than sufficient
 

bjf66

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managed to get the other stringer cleaned up and opened floor up around when the stringer joint will be.
most probably end of putting down new floor at rear half of boat
floor was foam
will start taking the sabre saw in weekend to the blast tank in front to remove

trailer getting sand blasted in weekend, so will need to rust prevent that early next week, and epoxy top coat
getting on with it
 

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bjf66

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Baylinerchuck
was up early this morning with cuppa thinking about transom, and had a read of your build, excellent write up
Due to boat being on dolly while trailer is being rebuilt, I need to grind in garage, so yep a little messy for a while
It amazing how much crap you have to take out of the boat with cutting and grinding
anyways we continue on
 

bjf66

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started to cut out the water ballast tank up front.
didn't know what to expect so, went nice and easy.
Looks like its just a fibre glass box with water in/out, previously had a bilge pump hooked up to discharge water
managed to get the left side of centre stringer cleaned up, need to keep cutting forward another 12"
the distance between stringers is 520mm (20.5"), so 'Im thinking I could move the fuel tank up a little, there is plenty of room to put a 60-75 gallon tank.
Not sure where the previous owner had the fuel tank, although there was some reinforced flooring near the transom area
removed some fibre glass which looked like it had dried out on the original layup,
I was expected to see the centre stringer water logged, however it was solid as the day it was put in there.
Will most probably cut some more out of the centre stringer so can utilise the space for fuel tank
More cutting tomorrow
 

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