Looks like a "20". The 20s are only something like 18'1" from the flat part of the transom to the bow eye. My best guess is that is an 82 or 83 as I think the 84s had the recessed cleat pockets and the 85s had the instrument cluster molded as part of the deck instead of removable.
Hi Must-ski: Attached is a picasas-web thread of the Hydrodyne 18 i/o proto-type for the HD 20 i/o. I saved these pics from the Craigslist add and did have a dialog with the owner and was considering taking a look at the boat. Another member who has both a HD 18 I/O and HD 20 I/O in his ownership, GAdyne, did visit the boat captioned to confirm that although similar to the lines of a 20, was in fact an 18. Based on the pictures provided Isaac, I believe that the a boat is from the same molds (top deck and hull) as the pics provided. The same windshield, the teak strip orientation, and the smaller amount of space in the interior also suggest this. measuring the beam (width) and length would confirm. Also some of the notables from the pics caption in the picasas-web are the HD 18 bat-wing trailer which would not work with the HD 20 I/O; way too short. You are correct in the top deck instrument cluster changes from the 1983/4 to 1985 and the recessed cleat issues, however, Van Owens 1983 HD 20 I/O boat #1 has recessed cleats as well. If this is an 18, I think Isaac has a very limited production, rare and unique, boat as was the other boat in the attached pics. If this is a HD 20 I/O, then we have boat #4 of maybe 7 produced, also rare in its own right. Here is the link. https://picasaweb.google.com/103493629086672686443/1978Hydrodyne18IOProtoTypeForHD20IO# KevinB-
Mike: I couldn't open the pics but great to hear from you. Please keep the info regarding the 20 i/o's coming if you find them. They are are not typical. There is no true account as to how many were built but my contact with Tom Miller in 2012 would sugest that 7 to 10 at most. My Best, Kevin-
I am with you Kevin. The boat looks much too narrow to be a 20, which if memory serves me is 19' 4" centerline. The wings were added to make it 20 overall to avoid hp limits. The late model Dyna's were lengthened and the wings removed to make them 20 or a little more centerline. This gives them a weight carrying advantage too. The hull is about 9 inches longer. jim
Hey Kevin, I'll try again, its not a pic but a link to a craigslist ad... looks like it was just restored https://fortwayne.craigslist.org/boa/4330124882.html copy and paste the URL to your web browser and it should take you right to the listing. If its still not working let me know... you should be able to click the link and go to the listing... Mike
Hi Jim: If Gadyne had not checked out the boat in the pics I posted, the only real gauge in length was the 18 bat wing trailer. Now there are potentially or apparently three HD i/o 18' boats from the late 70's that have similar top decks (note no bubble top aka instrument clister) to the later 20 i/o's which I think is pretty cool. must have been some sort of transition that must have fizzled as the 20 outboards were introduced. I kind of favor the alpha I and II i/o marine engines to the outboards because they are not far removed from regular vehicle blocks and are easy to work on. However, I also admire the pull capacity of the twin and tripples. Going to get out of this northen (arctic) climate down in Fl this spring.
I agree with your comments about the small block/alpha drives. And I agree with the collectibility of those boats if you are into that. About 15 years ago I got interested in outboard technology. I met a guy that really knows outboards. The bottom line is that there are a ton of parts and motors out there that REALLY perform on the 18. They are easy to work on and the power to weight ratio cannot be denied. We went through his parts stockpile just to see what we could do if we built a custom motor. We decided that 200-225 hp was easily attainable on 87 octane at a weight of between 300-350 pounds. My motor produces 164 hp, it is quiet, and weighs 370. It outperforms a 18 I/O in all respects. It does everything I want it to do so I don't need the custom motor. It draws considerably less water than the I/O so it is ideal for working off my beach. It is a converted I/O and the details have been documented here. The HP limits and flotation requirements killed the 18 outboard and the flotation requirements killed the 18 hull. The 20 and the 17.6 were the logical replacements and there is little demand for them. The 20 I/O makes sense to me because it has the flotation to carry the weight, but no demand. My 18 outboard is the most fun boat I have ever driven, and at age 76 I still enjoy pulling my daughter and she still does all the moves that she did to win the nationals in 2004. jim
