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Author Topic:   notched transom redo?

13whaler1965 posted 10-28-2001 10:02 PM ET (US)
I'm new to this site and am amazed at the info and energy i have found here to whalers. You have probaly addressed this topic before, but I would appreciate any insight. The model I currently own was built for a 15" shaft motor & I have a 20" 30hp with a step-up bracket. I want to repower with a new motor w trim and tilt and was considering going to a 50. I know the boat was rated for a 40. Would I be better off building up the notch with glass or do you think the bracket is just as strong. My concern is the bracket is held on with four bolts. Thanks
andygere posted 10-29-2001 03:09 AM ET (US)
Why not just put a 15" shaft motor on it? Tohatsu/Nissan makes a 15" 40 hp with tilt/trim, priced way less than Merc, Yam or Ev/J.
Highwater posted 10-29-2001 02:39 PM ET (US)
The following thread addressed some aspects of this topic:
http://continuouswave.com/ubb/Forum4/HTML/000475.html
13whaler1965 posted 10-29-2001 10:16 PM ET (US)
I checked on the nissan/tohatsu and was told that last year was the last year of the 15'40hp. The difference in the price of a nissan vs, merc was only about $250.00 and i was told parts are hard to come by and very expensive
jimh posted 10-30-2001 12:14 AM ET (US)
If you do undertake a re-working of the transom to increase the height to 20-inches from 15-inches, I would caution that unless this modification is very well done it could have a negative impact on the value of the boat.
I think most people would prefer to buy an intact Whaler transom cut for a 15-inch motor than to buy a 20-inch transom which was built on to the original by a Do-It-Yourself-er.
On the other hand, if the transom build up is accomplished in a professional manner and looks every bit a part of the Whaler original hull, then that is probably a better solution to the problem of re-powering the boat with a 20-inch shaft engine.
Highwater posted 10-30-2001 06:32 PM ET (US)
Is your 15" transom really 15"? I have a 1972 13' and what I have been calling a 15" transom is actually 16.5" from the top of the transom to the bottom of the hull. Was that the actual height of all 15" transoms, and if so, why are they called 15" transoms?
13whaler1965 posted 10-30-2001 06:36 PM ET (US)
Good point, I had thought that with the bracket, the only harm was four 1/2 holes in the transom. If someone wanted to restore, it would be easy to fill and glass.
I guess I need to decide on an engine, then worry about hanging it . Thanks
lhg posted 10-30-2001 07:00 PM ET (US)
It is very difficult to build up an old 13' transom to 20" in a professional manner, and achieve the needed strength. I would not recommend it at all.
A modern transom jack is the way to accomplish this objective, and for a lot less money and work.
But the 20" engine is the way to go, as BW discovered back in 1973!
Tom W Clark posted 10-30-2001 08:26 PM ET (US)
Highwater, the 15" transom height is measured vertically, or more precisely, perpendicular to the keel. Since the 13' hull's transom has a pronounced lean, over 20° I believe, the distance along the transom will necessarily be greater. Imagine a right triangle with the altitude of 15" and the hypotenuse of 16.5". The angle of the hypotenuse will look like the 13's transom in profile.
At any rate transom heights are not exact; there is always room for adjustment on the motors, and variation among manufacturers.
Highwater posted 10-30-2001 09:18 PM ET (US)
Right. Thanks for explaining that to me, Tom.
andygere posted 11-01-2001 02:51 AM ET (US)
Tohatsu/Nissan still list a 15" 40 hp on their website. There is an outfit (I beleive near New Orleans) that offers deep discounts on these motors and will ship. Check some earlier posts on this topic to find out where. Merc does not offer a 15" 2 stroke anymore. I suspect it is a conspiracy to get all the old 13's retired so they can sell more "new" 13's. If I still had my '72 13 it would have been my choice. I think the Tohatsu DI 90 is also an interesting alternative for the Montauk, especially here in CA where carbed 2 strokes are no longer sold.

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Author	Topic: notched transom redo?
13whaler1965	posted 10-28-2001 10:02 PM ET (US) I'm new to this site and am amazed at the info and energy i have found here to whalers. You have probaly addressed this topic before, but I would appreciate any insight. The model I currently own was built for a 15" shaft motor & I have a 20" 30hp with a step-up bracket. I want to repower with a new motor w trim and tilt and was considering going to a 50. I know the boat was rated for a 40. Would I be better off building up the notch with glass or do you think the bracket is just as strong. My concern is the bracket is held on with four bolts. Thanks
andygere	posted 10-29-2001 03:09 AM ET (US) Why not just put a 15" shaft motor on it? Tohatsu/Nissan makes a 15" 40 hp with tilt/trim, priced way less than Merc, Yam or Ev/J.
Highwater	posted 10-29-2001 02:39 PM ET (US) The following thread addressed some aspects of this topic: http://continuouswave.com/ubb/Forum4/HTML/000475.html
13whaler1965	posted 10-29-2001 10:16 PM ET (US) I checked on the nissan/tohatsu and was told that last year was the last year of the 15'40hp. The difference in the price of a nissan vs, merc was only about $250.00 and i was told parts are hard to come by and very expensive
jimh	posted 10-30-2001 12:14 AM ET (US) If you do undertake a re-working of the transom to increase the height to 20-inches from 15-inches, I would caution that unless this modification is very well done it could have a negative impact on the value of the boat. I think most people would prefer to buy an intact Whaler transom cut for a 15-inch motor than to buy a 20-inch transom which was built on to the original by a Do-It-Yourself-er. On the other hand, if the transom build up is accomplished in a professional manner and looks every bit a part of the Whaler original hull, then that is probably a better solution to the problem of re-powering the boat with a 20-inch shaft engine.
Highwater	posted 10-30-2001 06:32 PM ET (US) Is your 15" transom really 15"? I have a 1972 13' and what I have been calling a 15" transom is actually 16.5" from the top of the transom to the bottom of the hull. Was that the actual height of all 15" transoms, and if so, why are they called 15" transoms?
13whaler1965	posted 10-30-2001 06:36 PM ET (US) Good point, I had thought that with the bracket, the only harm was four 1/2 holes in the transom. If someone wanted to restore, it would be easy to fill and glass. I guess I need to decide on an engine, then worry about hanging it . Thanks
lhg	posted 10-30-2001 07:00 PM ET (US) It is very difficult to build up an old 13' transom to 20" in a professional manner, and achieve the needed strength. I would not recommend it at all. A modern transom jack is the way to accomplish this objective, and for a lot less money and work. But the 20" engine is the way to go, as BW discovered back in 1973!
Tom W Clark	posted 10-30-2001 08:26 PM ET (US) Highwater, the 15" transom height is measured vertically, or more precisely, perpendicular to the keel. Since the 13' hull's transom has a pronounced lean, over 20° I believe, the distance along the transom will necessarily be greater. Imagine a right triangle with the altitude of 15" and the hypotenuse of 16.5". The angle of the hypotenuse will look like the 13's transom in profile. At any rate transom heights are not exact; there is always room for adjustment on the motors, and variation among manufacturers.
Highwater	posted 10-30-2001 09:18 PM ET (US) Right. Thanks for explaining that to me, Tom.
andygere	posted 11-01-2001 02:51 AM ET (US) Tohatsu/Nissan still list a 15" 40 hp on their website. There is an outfit (I beleive near New Orleans) that offers deep discounts on these motors and will ship. Check some earlier posts on this topic to find out where. Merc does not offer a 15" 2 stroke anymore. I suspect it is a conspiracy to get all the old 13's retired so they can sell more "new" 13's. If I still had my '72 13 it would have been my choice. I think the Tohatsu DI 90 is also an interesting alternative for the Montauk, especially here in CA where carbed 2 strokes are no longer sold.