Can anyone advise on the proper outboard motor specs. for a 25 1976 lead keeled sailboat. I have an inboard motor that will need to be overhauled so during the upcoming season I want to buy an outboard motor while I wait to have the inboard fixed. My boat will be situated in a bay in the vacinity of the Cape Cod Canal so I hear the currents are quite strong there. I thought an outboard such as a 20 would serve me better than a 9.9. Any thoughts on the weight and whether the torque would be too much for my transom. I have been told by many that my boats hull and transom were made stronger in 1976 than they currently are as engineers overengineered boats at the time.
20 HP Mercury, too much??
- Thread starter Before the Bell
- Start date
- Status
Overkill!!!
20 hp is overkill for a 25' boat. What HP was the original inboard??? My brother had a 25' pacific seacraft and it came equiped with a 8 hp yanmar. He said that that was plenty of power. My old Macgreagor 26 would do hull speed at half throttle with a 7.5 hp honda. It came equiped with a 4hp that was OK. A 9.9hp should be plenty with some power left over for wind and waves. But you can't go faster than hull speed and it is bad for a motor to run at idle speeds for long periods of time. With a 20hp it would probably be at 25% of power or less in normal conditions. Motors last longer when ran at 75-80% of max. Tom
20 hp is overkill for a 25' boat. What HP was the original inboard??? My brother had a 25' pacific seacraft and it came equiped with a 8 hp yanmar. He said that that was plenty of power. My old Macgreagor 26 would do hull speed at half throttle with a 7.5 hp honda. It came equiped with a 4hp that was OK. A 9.9hp should be plenty with some power left over for wind and waves. But you can't go faster than hull speed and it is bad for a motor to run at idle speeds for long periods of time. With a 20hp it would probably be at 25% of power or less in normal conditions. Motors last longer when ran at 75-80% of max. Tom
Archived topic
Everytime the subject of hanging an outboard on the transom of a Hunter Cherubini is brought up, it is discouraged. There are a variety of reason why it is not a good idea. The top of the list is that gasoline is explosive stuff. Then, hanging an outboard on a brillantly and beautifully designed yacht is a travesty (IMHO) I won't labor through more than the two resons I have given. I still discourage it. I would wait until the inboard is overhauled. To answer your questions, the transom on a H25 should hold a 75 to 125 lbs. outboard without any problem. Give it a good backing by adding a 3/4 inch plastic or wooded support plate. 15 hp. should be enough to handle the current in relation to the weight of the boat, but you should schedule departures and returns considering tides, currents and so on regardless. That's my two cents worth. I do wonder why it will take all season for the inboard to be overhauled. Then, I remember spending a little time in Cambridge during my youth and that the season is only two weeks long.
Everytime the subject of hanging an outboard on the transom of a Hunter Cherubini is brought up, it is discouraged. There are a variety of reason why it is not a good idea. The top of the list is that gasoline is explosive stuff. Then, hanging an outboard on a brillantly and beautifully designed yacht is a travesty (IMHO) I won't labor through more than the two resons I have given. I still discourage it. I would wait until the inboard is overhauled. To answer your questions, the transom on a H25 should hold a 75 to 125 lbs. outboard without any problem. Give it a good backing by adding a 3/4 inch plastic or wooded support plate. 15 hp. should be enough to handle the current in relation to the weight of the boat, but you should schedule departures and returns considering tides, currents and so on regardless. That's my two cents worth. I do wonder why it will take all season for the inboard to be overhauled. Then, I remember spending a little time in Cambridge during my youth and that the season is only two weeks long.
splite the dfference
and go with a 15 hp. You will also want to think about the prop size and pitch. Talk to the outboard retailer or to a good prop shop for suggestion. The props that are "standard" are not always suited to your boat. You will need more torke rather then speed, you will go a little slower but you will have more control in the canal with its currents and not be overworking the engine.There is a a weigth difference in 2 stroke vs. 4 stroke so depending on what you want check the weight. You may need to reinforce the engine bracket to compensate for a larger engine that weights more.
and go with a 15 hp. You will also want to think about the prop size and pitch. Talk to the outboard retailer or to a good prop shop for suggestion. The props that are "standard" are not always suited to your boat. You will need more torke rather then speed, you will go a little slower but you will have more control in the canal with its currents and not be overworking the engine.There is a a weigth difference in 2 stroke vs. 4 stroke so depending on what you want check the weight. You may need to reinforce the engine bracket to compensate for a larger engine that weights more.
Easy answer
20 hp is overkill, and the other posters have explained why. You are correct to be concerned about the transom's strength; if it wasn't originally designed to accomodate an outboard, you don't want to stress it any more than absolutely necessary with one. That means no 20 hp engine. Older fiberglass boats were built more heavily than they are today, but by the mid to late 70's, engineers were getting the hang of things and moving towards modern construction methods. There is no way of knowing where your boat is on the sliding scale, and unless you can talk to the manufacturer, you don't want to find out by opening up the throttle, hearing a great big crack, followed by a splash and then silence. I had a 9.9 on my Oday 23, and it was more than enough. I switched to an 8 hp, and I still hit hull speed at less than WOT. For comparision, my boat (fully loaded) displaces about 3500 lbs. Whatever engine you choose, make sure it is a long shaft (at least 20") model, extra long shaft (25") if possible.
20 hp is overkill, and the other posters have explained why. You are correct to be concerned about the transom's strength; if it wasn't originally designed to accomodate an outboard, you don't want to stress it any more than absolutely necessary with one. That means no 20 hp engine. Older fiberglass boats were built more heavily than they are today, but by the mid to late 70's, engineers were getting the hang of things and moving towards modern construction methods. There is no way of knowing where your boat is on the sliding scale, and unless you can talk to the manufacturer, you don't want to find out by opening up the throttle, hearing a great big crack, followed by a splash and then silence. I had a 9.9 on my Oday 23, and it was more than enough. I switched to an 8 hp, and I still hit hull speed at less than WOT. For comparision, my boat (fully loaded) displaces about 3500 lbs. Whatever engine you choose, make sure it is a long shaft (at least 20") model, extra long shaft (25") if possible.
What???
I really do not understand two things. First of all why think of an outboard when used engines are available as well as the ability to rebuild your current engine in a short period of time ( two weeks or less ). The second, have you actually priced outboards in the HP range that you are looking at? It will be more cost effective to fix what you have. I was in the business for many years and the direction you are headed does not make sense from a monetary standpoint or the disruption of the boat you have that was not designed for an outboard. When you look at your transom I think you will find there is no reinforcement for an outboard mount. The stress reinforcement will be in the area where your inboard prop shaft comes through the hull not in the transom. To mount an outboard safely you would need to reinforce the transom with plywood or a material that will spread the stess load across a major portion of the transom which will also cost time and dollars. Afterwards you will have to reverse the process to get your boat back to original. This whole thing seems like your are trying to push a cart up a hill with a rope, just a personal observation.
I really do not understand two things. First of all why think of an outboard when used engines are available as well as the ability to rebuild your current engine in a short period of time ( two weeks or less ). The second, have you actually priced outboards in the HP range that you are looking at? It will be more cost effective to fix what you have. I was in the business for many years and the direction you are headed does not make sense from a monetary standpoint or the disruption of the boat you have that was not designed for an outboard. When you look at your transom I think you will find there is no reinforcement for an outboard mount. The stress reinforcement will be in the area where your inboard prop shaft comes through the hull not in the transom. To mount an outboard safely you would need to reinforce the transom with plywood or a material that will spread the stess load across a major portion of the transom which will also cost time and dollars. Afterwards you will have to reverse the process to get your boat back to original. This whole thing seems like your are trying to push a cart up a hill with a rope, just a personal observation.
Re: What???
Trust me, the last thing I want to do is to convert my boat from a mini-yacht (inboard engine and lead keel) to a daysailing looking boat. However, after giving 2500.00 in advance to Brewer's Marine (Plymouth), and asking them three times to rebuild my engine, they ignored me. So after a long, cold and snow ridden winter I have no motor. I have decided to move my boat from such a poor servicing marina to a very excellent one, the only problem is that they neither have the time or man-power at this time to rebuild my engine!! I'm not going to miss another summer of sailing so I'm going to go outboard. I have refurbished this whole boat including new hand rails, tiller, custom cabinet doors, compass, bilge pump, antenna, new bottom paint, topside paint, deck paint, new lettering for a new name, new hulliner, etc. so I'm going to enjoy my boat!!!!
Trust me, the last thing I want to do is to convert my boat from a mini-yacht (inboard engine and lead keel) to a daysailing looking boat. However, after giving 2500.00 in advance to Brewer's Marine (Plymouth), and asking them three times to rebuild my engine, they ignored me. So after a long, cold and snow ridden winter I have no motor. I have decided to move my boat from such a poor servicing marina to a very excellent one, the only problem is that they neither have the time or man-power at this time to rebuild my engine!! I'm not going to miss another summer of sailing so I'm going to go outboard. I have refurbished this whole boat including new hand rails, tiller, custom cabinet doors, compass, bilge pump, antenna, new bottom paint, topside paint, deck paint, new lettering for a new name, new hulliner, etc. so I'm going to enjoy my boat!!!!
Tough Question
A new outbeard (20" shaft) will be in the two grand range. Also, having lived closly with a later model h25 I can't imagine where they stuffed the one lunger.If you go to an outboard, you're gonna have to get rid of th inboard iron, or your trim will be in the crapper. Myexperience with an 81 h 25 is that the transom is 1'plywood with 3/8" glass on either side. Should support a ballsy 9.9 4 stroke. Regards, Jim
A new outbeard (20" shaft) will be in the two grand range. Also, having lived closly with a later model h25 I can't imagine where they stuffed the one lunger.If you go to an outboard, you're gonna have to get rid of th inboard iron, or your trim will be in the crapper. Myexperience with an 81 h 25 is that the transom is 1'plywood with 3/8" glass on either side. Should support a ballsy 9.9 4 stroke. Regards, Jim
Don't Trash the Inboard Yet
Throw a used or borrowed OB on there and see if you can get someone to work on your motor at your new place. I do not think you need more than an 8HP motor on there and by no means do you need more than a 9.9 sometimes less is more.
Throw a used or borrowed OB on there and see if you can get someone to work on your motor at your new place. I do not think you need more than an 8HP motor on there and by no means do you need more than a 9.9 sometimes less is more.
my $0.02 worth
get the minimum outboard that will safely deal with the curents/tide in your area and use it for the season. use plenty of wide/solid backing on a retractable mount. from all i've seen 8-9.9 s/b plenty but you e coast guys deal with allot rougher conditions than on my lake. i'd be looking to the future and possubly get the type mount that goes real low so maybe you could even get away with a short shaft engine that you could later use for a dingy. in the mean time i would start pulling the inboard out myself. i've built allot of engines, (but not a diesel yet), and know that there is very little that is terminal on any engine this side of launching a rod through the block. if the access to the engine is horrible it may have to come out in pieces or some "modifications", access panels or such may be nesessary and nice for future maintenance, but DIY. ...or at least get it out yourself and if you just don't have the inclination to tackle rebuilding it yourself there's got to be an engine rebuilder somewhere that will take it from there. i had never built a chevy 396 till i had one. i had never built an outboard till i had one. i had never built a BMW engine till i had one. if i had a broke diesel i guess i'd learn how to build that too. and the benefits of being able to fix anything on it after that kind of experience are priceless...you are no more at the mercy of boatyard apes! if it can be put together and made to work in the first place, you can take it apart, figure out whats broke, and you can put it back together. engines aren't magic. this is certainly MHO and you may just not want to fool with it. personally, i'd love to have a small 25 footer w/ a 8hp, (or a contessa 26 with one.) the difference in future resale value alone would probably be worth the effort.
get the minimum outboard that will safely deal with the curents/tide in your area and use it for the season. use plenty of wide/solid backing on a retractable mount. from all i've seen 8-9.9 s/b plenty but you e coast guys deal with allot rougher conditions than on my lake. i'd be looking to the future and possubly get the type mount that goes real low so maybe you could even get away with a short shaft engine that you could later use for a dingy. in the mean time i would start pulling the inboard out myself. i've built allot of engines, (but not a diesel yet), and know that there is very little that is terminal on any engine this side of launching a rod through the block. if the access to the engine is horrible it may have to come out in pieces or some "modifications", access panels or such may be nesessary and nice for future maintenance, but DIY. ...or at least get it out yourself and if you just don't have the inclination to tackle rebuilding it yourself there's got to be an engine rebuilder somewhere that will take it from there. i had never built a chevy 396 till i had one. i had never built an outboard till i had one. i had never built a BMW engine till i had one. if i had a broke diesel i guess i'd learn how to build that too. and the benefits of being able to fix anything on it after that kind of experience are priceless...you are no more at the mercy of boatyard apes! if it can be put together and made to work in the first place, you can take it apart, figure out whats broke, and you can put it back together. engines aren't magic. this is certainly MHO and you may just not want to fool with it. personally, i'd love to have a small 25 footer w/ a 8hp, (or a contessa 26 with one.) the difference in future resale value alone would probably be worth the effort.
What engine are we talking about????
You really need to talk to a good mechanic!!!! If all else fails find a good backyard mechanic. You might be able to buy a new diesel and have it installed by the company that sells it to you. What is wrong with the diesel???? Is it totally shot or just needs a head job??? Some of these mechanics act like they are doing rocket science. A small diesel isn't that complicated.
You really need to talk to a good mechanic!!!! If all else fails find a good backyard mechanic. You might be able to buy a new diesel and have it installed by the company that sells it to you. What is wrong with the diesel???? Is it totally shot or just needs a head job??? Some of these mechanics act like they are doing rocket science. A small diesel isn't that complicated.
tractor rebuild
some of the small diesel moters where put in tractors and if the tractor guys can get the parts they can do a nice rebuild on your block and then there are a bunch of guys that could put it back in the boat if You dont have the time or experience to do the job your self I helped a guy take out a 18hp DL from a catalina 30 and we had the moter out in one pice inabout two hrs there wasnt much to it.The guy had all the tools out and the sink cabinet siting on the side the yard guys pulled the moter out with a crain and droped it in the truck .and Ill say the tractor guys are working way cheeper then the marine guys by about half.but we had to drag the moter to ther shop about 1hr away .Ive learned alot about boats in the last 5 years and its becouse I cant get anty body that wants to work on a sail boat we must stick together. thanks to the guys on this site Thanks to all. John
some of the small diesel moters where put in tractors and if the tractor guys can get the parts they can do a nice rebuild on your block and then there are a bunch of guys that could put it back in the boat if You dont have the time or experience to do the job your self I helped a guy take out a 18hp DL from a catalina 30 and we had the moter out in one pice inabout two hrs there wasnt much to it.The guy had all the tools out and the sink cabinet siting on the side the yard guys pulled the moter out with a crain and droped it in the truck .and Ill say the tractor guys are working way cheeper then the marine guys by about half.but we had to drag the moter to ther shop about 1hr away .Ive learned alot about boats in the last 5 years and its becouse I cant get anty body that wants to work on a sail boat we must stick together. thanks to the guys on this site Thanks to all. John
20 HP OB
I can address this quite directly. I had a 15 HP mounted in an engine well on my Coronado 25 and it was more than I could use. At 2/3 throttle, it would drive the stern under and flood the well. I swapped it even for a 10 HP, saved weight and fuel and gained a knot.
I can address this quite directly. I had a 15 HP mounted in an engine well on my Coronado 25 and it was more than I could use. At 2/3 throttle, it would drive the stern under and flood the well. I swapped it even for a 10 HP, saved weight and fuel and gained a knot.
- Status