What's involved in replacing fiberglass decking

I suggest that you get two professional estimates. One to replace the fiberglass deck and one to replace that plus the wood deck below.

Seems your asking allot about this Ditmar. When you get serious, You need a good surveyor familiar with this type of build. We are only able to guess without hands & eyes on.
I'm not meaning to stop you from asking questions or pop any bubbles here, really just trying to help.
Glass over rubber over wood. Who knows without digging into it.

Good luck and keep us up on your experiences.
,rc

I don't see the point of the membrane. And quite frankly think it could be the cause of the delamination. As to the repair, no one could give you any kind of real estimate until the sub deck is exposed IMO. And even then it would be ball park at best. It could easily turn in to a big can of worms.

I don't know who told you that but it's incorrect. That boat, WILD EAGLE was built as BOUNDER for RV pioneer John Crean who is no longer with us. Before BOUNDER Crean built another Ditmar Donaldson PROWLER 76. It's now PANCHOS.

Ditmar Donaldson built some iconic boats for some very high profile yachtsmen and fishermen. Including the 82' Dorsal which was a fixture on the southern California sportfishing scene back in the 70's and 80's.

Howard Hughes' former Ditmar Donaldson is currently in Newport Beach, CA. It's name is SUNDANCE.

Same broker that told you about Howard Hughes? You need to have someone, willing to do the job, give you an actual estimate. I suspect that you'll find that the current owner already got an estimate which promted the sale.

I suspect that if you're looking at a 70' wood boat you have a lot of time on your hands or a ton of money. If the former, maybe you'd like to learn a new trade and rebuild the deck yourself. Just remember the old boat sale tag "Boat for sale due to divorce (and divorce due to boat)".

The fiberglassed decks I have repaired used the wrong resin (polyester), and wrong glass (WR). The glass is only to make the skin strong, not strengthen the wood. The old glass was peeled off with pliers after slicing (circular saw/carbide blade). The substructure was usually good. Grind clean. This "prep phase" can be done by unskilled labor. Next, saturate deck with a thin epoxy. Lay 6-10 oz. cloth. Then a (colored) gel coat (talc filled resin) rolled over. Any "glasser" can do this...all done at one time. Last, sand, paint, add non-skid.

Now your cooking and serious.

Don't call just one surveyor, interview a few of them until you find someone that really understands these boats and communicates well with you.

Well that is about it... couple comments.

First whatever you go over must be sound... you cannot apply whatever... on cracked, rotted or deteriorated material. So you have to fix any unlaying problems.

The deck should have at least .01" (.25mm) to .02" (.5mm) buildup of epoxy resin either as the first layer rolled on or brushed on wet (his comment about saturate) and sufficient buildup to form a moisture barrier. This may take 2 to 4 applications to achieve. Then the glass fabric put on for reinforcement or protection. The glass must be fully wet out with no dry fibers... they become capillaries for the moisture to migrate! Then the the underlaying finish coat of epoxy over the glass which needs the UV protection built into the resin... and of course the filler also helps in this.

The final finish should be a two component poly urethane which is UV resistive. The single component polyurethanes are not as UV resistive and not moisture resistive... in fact in the marine environment they will become hazy due to humidity... and go to hell quickly.

The UV aspect on decks is MORE important than the waterproof aspect as usually the deterioration is due to UV damage which then opens the material either through cracking or porosity to the moisture damage from migration.

Epoxy is universally very susceptible to UV but very resistive to moisture. So epoxy resins and paints don't work well over the long haul in sun exposure.

Two component catalyzed Polyurethanes are excellent at UV / sun exposure but not as good at being moisture barriers.

Polyester is bad at both.

Another comment. I am not an expert on your particular boat but it seems to me the rubber membrane is just that a moisture barrier. Reminiscent of a rubber membrane roof on shore.

I would think that is a big problem with the durability of the system is the rubber. As it can keep moisture out but also in. This is a problem is if the bond is not perfect and water gets in (around the edges) it gets trapped in and do its evil deed of deterioration.

Any luck with that broker .I also have looked at vessel and a friend of mine says the foredeck needs pulled of and rot replaced ? any truth to that

70 Ditmarr Donadlson

Is the boat worth looking into if A guy wants a project?

Any update - surveyor still making notes of rot damage?