Replacing an old thrust board?

[A Good Ribbing]

Hi, despite the whimsical username, I only have a SIB, a 1986 Zodiac MKII Grand Raid, and it is in need of some repair. I took it in to a local shop to repair a hole in the floor, and get a new inflatable keel, where they pointed out that the DPO (dipshit previous owner) put plywood in as the thrust board. The tech proceeded to tell me how the thrust board should be made out of some exotic thickness super-duper wood and glues into the floor with some wooden wings, and how he'd need to remove it all and custom-make one and blah blah blah to the tune of $1000 (525 pounds sterling). I'm getting the lube ready, but I figured I should consult with the hive mind of the internet before I bend over. Is there a cheaper way to go? Can I get away with some fresh plywood in front of the alum floorboards, or do I need to have the whole thrust board structure rebuilt to spec? Apparently Zodiac no longer makes a thrust board for this model. Keep in mind that I paid $1500 (~780 pounds) for the boat with a running Suzuki DT65 so I don't really feel like spending too much money. It just needs to be "good enough" and not fall apart any sooner than necessary. Cost-benefit and all that crap.

Thoughts?

[prairie tuber]

IF the tthrust board is not properly secured in the boat the boat will not have good longitudinal stiffness and performance will suffer greatly. I'm pretty sure that the thrust board is quite simpy a marine mahogany plywood, but it should be be shaped properly.

Hard to say if the boat is worth it. Being a Grand Raid, it is most likely made of hypalon (there was a few years where Grand Raids were made with PVC). Hypalon will have several times the life expectancy than PVC.

What's the condition of the rest of the boat? Particularly around the transom?

[A Good Ribbing]

Originally Posted by prairie tuber

IF the tthrust board is not properly secured in the boat the boat will not have good longitudinal stiffness and performance will suffer greatly. I'm pretty sure that the thrust board is quite simpy a marine mahogany plywood, but it should be be shaped properly.

Hard to say if the boat is worth it. Being a Grand Raid, it is most likely made of hypalon (there was a few years where Grand Raids were made with PVC). Hypalon will have several times the life expectancy than PVC.

What's the condition of the rest of the boat? Particularly around the transom?

Transom is alright though getting old (flaking finish, some attaching flaps of fabric are slightly loose), no holes, no patches, I believe it's hypalon and holds air indefinitely. One bulkhead is out. For the most part it's alright. From what you're saying, it sounds like a good idea, particularly with a DT65 pushing it through rough water.

[prairie tuber]

DT65? What is the max hp rating on the transom plate showing?

[samt]

Most sibs with usual plywood floors usually have outboards around 15hp. So a 65hp will certainly require the extra strength.

The MKII is rated upto 50hp
The MKIII is rated upto 65hp

You either have the MKIII or a overpowered boat with a dodgy thrust board!!

[jyasaki]

I'd check on insurance for that thing, especially if you're in the US. With a 65, you're exceeding the max engine rating, which means that your insurance is probably going to be one of those non-paying policies, should you get in an accident.

That's assuming the boat is the 13'9" model (GRII) and not the 15'5" (GRIII).

jky

[A Good Ribbing]

Sorry, it must be the GRIII. It is 15.5ft.

[prairie tuber]

A new hypalon GR III (boat only) with aluminum floorboards would run you about 8 x what you bought the boat and motor for.