I know this sounds insane I have a 1979 H27 with a 10 hp johnson kicker on the port side . in a headwind and the current against me it can take forever to claw my way home also if the nose come off the wind it would spin me like a top and the kicker was'nt strong enough to even slow the spin down much less put her back in the wind . I thought if I put another 10 hp on the other side I could control it better and double my power . Also I am planning a trip from St. Agustine fla to Nashville Tn where I am from so wouldnt it be better for me to have as much power as possible to go up river all the way to Tn My boat had a volvo penta inboard which was good for scrap only I do have a yamar SB8 I could put in it that looks to be alot of work and expence the shaft plate and motor mounts would have to be changed a little input would be nice I am Dazed and Confussed
H27 twin outboards ?
- Thread starter slowhandsailor
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I'm with Jackdaw! 10hp is more than you can effectively use. 20 np will just double your fuel cost. Look into having your boat trailered up hill.
what about sailing up north and going down river just dont want to trailor it anywhere I have all the time left in my world to get there dont have to work anymore so why not take a few months and just go
While a 10HP diesel engine is adequate for the h27 a 10HP outboard just does not have the bite. I have seen conversions for the h27 but none under 15HP. I would recommend you keep a single engine and get yourself a 20 HP. Running two engines can be complicated and would add quite a bit of weight on the transom.
Thank you all for the advice inboard seems to be the way to go I will sell the outboard to install the yanmar . if Im not going to use it sell it thanks again
I assume when you say you have a sb8 you are referring to the YSB 8. I had the 12 in a Hunter 30. These engines are as old as the boats even assuming it is in good running order it will more than likely not put out 8 hp. Also bear in mind the parts are not plentiful for this series anymore.
I do think the inboard will improve power handling forward but may make docking harder due to prop walk. Other concern is that the engine rotates counterclockwise rather than clockwise so assuming you plan on running you need a prop with the reverse pitch or alternatively need to use forward as revere and visa versa. You can get away with that if it has the original transmission since its one to to one in either direction.
I do know the 30 with a heavy tide like what I experienced going to Cape May often could make no more than 1 knot into it. I would not expect the 8 to do better.
On the plus side they are incredibly reliable engines and lots of folks know them so help will be available. If its helpful I think I still have a PDF of the manual someplace as the 8 and 12 were covered in the same one.
I do think the inboard will improve power handling forward but may make docking harder due to prop walk. Other concern is that the engine rotates counterclockwise rather than clockwise so assuming you plan on running you need a prop with the reverse pitch or alternatively need to use forward as revere and visa versa. You can get away with that if it has the original transmission since its one to to one in either direction.
I do know the 30 with a heavy tide like what I experienced going to Cape May often could make no more than 1 knot into it. I would not expect the 8 to do better.
On the plus side they are incredibly reliable engines and lots of folks know them so help will be available. If its helpful I think I still have a PDF of the manual someplace as the 8 and 12 were covered in the same one.
Before you change anything else, buy a high thrust prop for the engine, probably something labled around a 7" pitch.
With a 6.5" regular prop my boat maxed out at 4.5kts under motor, and any chop would quickly cut that by 1kt or more. Large waves left me near standstill. I switched to a 7.5" regular prop, motored at 5.5kts, cruised at 4.5kts, and could do 4kts+ in mild chop, and 2.5+ where I couldn't have hardly made headway before. However it was over propped and the engine was always bogged down a little, and I still had almost no power in reverse.
This year, changeing absolutly nothing else on the engine, I switched to a 4 blade high thrust prop, I can motor at 6.2kts now, cruise at 5kts, and power through chop at 4.5kts, where I would have been doing 2.5kts with the last prop, and nearly nothing with the original prop. I can reverse just as good as going forward now which makes docking much easier (both coming and going), and as a pleasant surprise, power boat wakes don't kill my speed too much anymore when motoring (they still knock the boat around, but I power through them without much loss of speed so the rocking doesn't last as long).
So before you go making radical changes, try a simple and cheap one, that may just do everything you need....
With a 6.5" regular prop my boat maxed out at 4.5kts under motor, and any chop would quickly cut that by 1kt or more. Large waves left me near standstill. I switched to a 7.5" regular prop, motored at 5.5kts, cruised at 4.5kts, and could do 4kts+ in mild chop, and 2.5+ where I couldn't have hardly made headway before. However it was over propped and the engine was always bogged down a little, and I still had almost no power in reverse.
This year, changeing absolutly nothing else on the engine, I switched to a 4 blade high thrust prop, I can motor at 6.2kts now, cruise at 5kts, and power through chop at 4.5kts, where I would have been doing 2.5kts with the last prop, and nearly nothing with the original prop. I can reverse just as good as going forward now which makes docking much easier (both coming and going), and as a pleasant surprise, power boat wakes don't kill my speed too much anymore when motoring (they still knock the boat around, but I power through them without much loss of speed so the rocking doesn't last as long).
So before you go making radical changes, try a simple and cheap one, that may just do everything you need....
Sailboat transoms are not designed to carry any motor over 10 hp as they are not thick like power boats which can. In addition, the hulls are displacement hulls, not planning hulls like power, thus you will only go so fast. Adding a second engine to the transom will stress the transom structure when if by chance both motors are going full blast but again the hull speed will not go any faster either. Food for thought.
A diesel motor usually turns a much larger and more powerful prop than a equal HP outboard. If you have a long shaft motor and re-prop it and you should be fine. A local prop shop can advise you about what to change.
Ray
Ray
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