The problem, to walk the fore deck with the boat stationary makes you feel seasick, like walking across a waterbed, the solution is to chop out the rotten core and replace with lashings of wests and marine ply.
Brimming with confidence having re-read an PBO article about a chap re-coring the deck of an old motor cruiser i did what i always do and reach for the tools that make the most noise, (damage) dust (damage) and....eh damage.
Having drawn a line 50 mm in from the edge all the way around the foredeck i reached for the grinder, then on looking at how clean the shed was and thinking how long it took to get it to that state i pulled out the jigsaw instead.
I successfully cut a 1 mm line all the way round then got busy with the chisels and wedges - would you believe it, the bond was incredible despite it being polyester and rotten and 40 years old it took all my strength (after quartering the original cut line) to pull out two pieces that made half the deck.
Now the damage could be seen, all the usual suspects: black balsa core, rotten plywood plank that looked like no adhesive whatsoever had been applied to it and a very strong vinegar smell . i decided to follow the route of the plank towards the fore-cabin and realised i'd need to take more of the deck moulding off.
With these last two pieces removed i could start making the core pieces and get them dry fitted, this went fairly quick so after double checking my prep and one last time with the hot air gun it was time for epoxy.
I don't know what it is about this stage in the work but no matter how well i set the tools and materials out it always ends up a bit of a bun fight, this particular job was to be no different. After more careful consideration of the west's manual todays recipe would be thickened with 407 (low density) and 402 (milled glass blend) the last one in particular as it would make the mix a lot more viscous therefore i wouldn't need to chase the stuff around the foredeck.
In the PBO article the chap uses big stones to way everything down, i had air pressure at my disposal so having made what looked like a very messy sandwich i wiped as much excess of the deck as i could (as i by now it was gelling) and got the peel ply and vac bag on.
With a flick of a button the deck pulled down an absolute treat and i now have a deck that's as stiff as a stiff thing with additional stiffeners, all i need do now is grind a 12:1 in the joint lines tape and fill.